Heating Help

radiant heat loss because of pex placement?

I have a 2800 sq.ft home. plus a 576' heated garage. 2 living levels.The lower level is a finished basement. There is radiant placed in aluminum fins on first floor and radiant in the cement of the finished basement. I have a trinity ti-200 propane boiler with 5 zones, 2 taco mixing valves and 1 grundfos pump. My problem is that the pex tubing in the finished basement was placed in 2'' of insulation, 3'' of sand, then 5'' of cement poured on top. It doen't seem to keep up during cold Maine winters. 10 degrees and under, the system runs constantly and temp downstairs drops to 64. Uptairs stays warm. Any suggestions??? Thanks- Peter

Heating the ground

If I understood your post correctly, are you are saying that the pex is entirely beneath the slab in sand? Is there is insulation and vapor barrier under the pex? Having the tubing not in the slab itself is a big problem, and if it is heating damp soil...all you are doing is wasting fuel.

radiant heat loss because of pex placement?

Yes there is a proper 2'' insulating pex tubing barrier with 3'' of sand on top. Then 4''to5'' of cement. The previous owner was trying to do the mass heating thought process that was whirling around in 2006. He had built 350 high class homes and this one was for him and his wife. Beautiful home but some times we get caught in the over thinking things trying to improve commen sense. As i said, the zone runs all the time during the winter and cannot keep up in real cold conditions. It does not help that i have berber carpet that has an r-value of 3, but even the tiled bathroom floor is only luke warm at times. I have thought of many ways to fix the problem but not at a cost effective way. Peter

the tiled bathroom floor is only luke warm at times.

I live in New Jersey that I imagine does not get as cold as it does in Maine. Design temperature where I live is 14F. I find my floor seldom gets to what I would say is "warm." When it is 50F outside, I put 75F water into the slab, and that is enough to maintain 69F in the house. When it is 14F outside, I need 112F in the slab. I can feel that if I am barefoot or wear thin socks. It got down to about 9F for a few hours last year, so I was putting 118F into the slab for a while. On days like that, my IR thermometer reveals floor temperatures in the high 80s; I consider that definately warm.

So "warmness" of the floor alone does not seem a good way to tell if you are supplying enough heat. It might be that the heat loss of the house is too great and more insulation, better windows, and air leaks may be needed. When my old non-modulating boiler was in use, the floors could get too hot for comfort when walking around barefoot. Try to avoid going over 120F water in the slab. If that won't do it, consider adding radiant panels on the walls or ceiling.

Heat sink

Heat sink is what was trying to be accomplished. The Berber carpet is killing any heat that it is producing. Bottom line the tubing is being insulated from below by the xps, and from above by the concrete floor, and Berber carpet. The area with the least r value barrier between them wins. So you are getting the heat just very slowly.

 A heat sink is what ends up being under an uninsulated slab such as in older radiant slabs, and newer incorrectly installed radiant slabs.
 It all works its just how much energy you want to use to do it as you are finding out. Trade the Berber for some low r carpet, and you will see some improvement.

Gordy

radiant heat loss because of pex placement?

Thanks Gordy, for a couple of years my wife and i have talked about tearing up the carpet and laying tile down to take away the carpet r-value. It is a $500,000 home and this is about the only weak aspect of the home. Too bad because 90% of the time the furnace keeps up, but cold stretches are when the heat is REALLY needed down stairs. Would you recomend tiling the floor and running 160 degree water temp? What about a circulator with a constant 160 degree water temp? at times other zones don't come on because of the demand of water temp? Thanks

heat loss calculation ?

Can anyone figure out the heat loss in water temp and heat loss in propane gallons with my carpet and pad being an R-value of 3 over concrete and heating 1300 sqft. I am just wondering how much of a heat gian i would have if i pulled the carpet and layed tile. The home is WELL  insulated. Thanks - Peter

a few numbers

Hello Panman,
I can't get any accurate figures with the sand.
I also believe, there is not enough insualtion underneath everything.
Furthmore, i can''t offer any thoughts about propane usage, without knowing hours of operation, design temp, heatloss etc.

Now having said all that here's what i can offer:
A 4 inch slab, without sand and with 2" of extruded insulation
with 1/2 inch pex spaced 12 inches apart and a R2.5 carpet will tranfer about 10 btu's per square foot, with 100 degree water.
The same set-up with 100 degree water and 1/2 tile with a R value of .4 will transfer about 23 btu's per sq ft.
Put another way, it would take 147 degree water to transfer the same 23 btu's wit R2.5 carpet.
Obviusly the numbers get worse with R3 and probably worse yet with the sand factor.

Peter

re-a few numbers

PeterNH, thank you for your input. You gave me valuable info. I am sure you read some of my posts and see why i am strongly considering losing the carpet. some of the info i got from websites said it would take 40 degree more water temp to get the same results as just tile on the concrete. You nailed it pretty well !!!!!!! My guess is that i would notice a considerable difference. Thanks again. PeterME.

insulation?

 
Hello Peter ME,
Are you sure there is 2" of extruded polystyrene insulation??
Do you know if the perimiter of the slab is insulated? HDow so? The perimiter insulation is critical.
Beware.
Based on the numbers i see, it looks like a reduction in water temp from 150 to 100 degrees, will only save 2-4000 btu's. But the sand is hard o figure.
Not very much savings, but it is dependent upon how the perimiter is insulated.
Any idea?
Anyway it's very well possible you will end up using more LP, not less.
By removing the carpet,  more heat will transfer into the room. The room temp will go way up to comfort levels, and it very well may cost more gas to achieve it.

Peter NH

high numbers

A do not believe the 50 degree numbers are correct. I use "radiant precision" as a reference on this kind of stuff. The 2" insulation is going to provide a good protection against downward heat loss. The lack of perimeter insulation will have some impact, less it is below the frost layer. With good downside insulation the heat is not lost, It just takes more time to get there. I would estimate a 10 degree water diff. It would take considerable brain damage to guestimate the energy savings, A SWAG would be a couple of percent of the total heating bill. I don't believe that from a cost savings point of view the tile is worth it.

Yes

Hello ZMAN,
I agree overall. There might be some savings from lower temps to by getting into condensing mode, but there will also be more usage via keeping the room temps at 72 vs 65 on cold days.
I think adding basebaord and or fan coils would be better than tearing up the whole floor. ugh.
The 47 degree number comes from Siggy's - Hyrdronics Design Stiudio.
Take it or leave it.
As far as the heat loss goes, yes, the perimeter insulation is a big factor.
If there isn't any, it make a big difference, and yes,  the deeper inthe ground the less it matters.

Peter

R?

Peter,
I was thinking you were comparing carpet and pad at R 1.4 to2.0 depending on type, to tile at .3. My personal experience in setting up reset curves has led me to think it is in the 10 degree range. I realize there is a serious SWAG factor. As a rule, I don't argue with Siggy!

re-insulation

PeterNH, Thanks for the reply. 3 1/2 sides of the finished basement sit into a hill, well below frost level and are insulated. Not alot of heat loss on the perimeters. You lost me on using more propane to heat the area without rug as apposed to with the carpet and pad??? i would think trapping the heat under the r-3 rug would put less heat into the air which means the furnace would have to run ATLEAST longer to heat the same area without the r-3 carpet??? Just trying to justify pulling the carpetand pad. Thanks- Peter

heat

Hi Pete,
I'm prettty sure i read somewhere in this thread, that the radiant spaces can't heat above 65 degrees when it gets real cold out.
Correct?
Let's forget about condensing for a moment.
The heat under the slab..has a big blanket in the form of a carpet and pad over it.
This is keeping the heat from getting into the house on the colder days.
If you remove the blanket, more heat will be able to get into the house.
Thus on the all the colder - coldest days, the radiant zones will now easily maintain the 72 degree thermostat setting.
Doing so will require more LP gas energy than what heppens now, being that the heat is kept in the blanket and not coming out of the boiler.
There will be some savings from lower water temps to the outside, but being  way down deep and well insulated, it won't be that much, the only other saving will come from the boiler possibly spending more time in condensing mode. Maybe.
Overall, i'm guessing it's a wash, ie not much savings, but yes, more comfort.
Certainly adding in the cost of tiling the floor it may never pay.

That's my opinion, sorry that's not what you want to hear, but i can't see any massive savings, if any at all.

Peter
NH

re-heat

Hey PeterNH, thanks for the reply. I do understand the logic behind the sarpet keeping my slab warmer as of now with the carpet but want to make sure i understand your reply.
Without the carpet i can get roughly 13 more btu's per square foot with same water temp.
My room would heat up quicker and demand would be met sooner causing my furnace to shut of sooner.
The slab would be cooler so when the room called for heat it would have to run longer to heat the slab to get the heat into the room, this is where it washes out!!
My question is could the carpet be causing the heat to go back down to the least resistance material (SAND) and when the carpet is gone, the heat would be generated into the room more than can be figured on paper. I ask this because the majority of the room is in the ground and well insulated and i feel the the time to heat the slab in between demands without the carpet heat sink effect would be more efficiant than what i have now. Just a thought. I am sure my wife and i at some point will tile, stain, ect. the floor and than the speculation will be over. The youngest goes to college this fall and i am fairly handy, so maybe i will tile it myself and see what happens. Thanks for the info. Peter

Something's not adding up

You have two mixing valves but only one circulator? Every mixed circuit would require its own circulator.

If your Ti200 has the Sentry 2100T controller (and I'm not sure whether there are any that don't), it's capable of outdoor reset. This can automatically vary the temperature that the boiler will heat the water to, based on measured outdoor temperature (an outdoor temp sensor is required.) If you're not currently using this, you should. If you are, it is possible that it's not configured correctly. Can your mixing valve(s) also be set incorrectly or malfunctioning? Do you have a schematic you could post, or some photos of the works that you could mark up to indicate what's what?

outdoor reset

If the slab is fed by a thermostatic mixing valve, it will fight the boiler ORC (unless the mixing valve is motorized and controlled on its own curve.)

Yes, clearly.

In an outdoor reset environment the thermostatic mixer can at best be a limiting device. That's why I think that their effect in this system has to be examined. Proportional mixing is possible (non-thermostatic, fixed mix ratio) or something motorized that has its own reset curve, either controlled by the boiler's ODR (not gonna happen here) or with its own ODR controller.

I thought that I'd ask for more facts before trying to state a diagnosis. :-)

radiant heat loss because of pex placement?

gorden. My outside reset temp is on and seems to be working fine. We had a temp of 36 and the outside reset read 37. The taco mixing valve that runs the 2 zones in the finished basement have a Mix and supply of 125. MAX temp is set at 130 and min set at 120 degrees. They were set at 80 and 90 degrees when i moved in, but could not come close to heating in colder weather. I have noticed that when 2 or more zones are running the other 2 take a while to kick on because the boiler cannot keep the temp up on all the zones at once. The top floor has 2 zones and has aluminum fins with  water temps that are set at 140 max supply.From what i have read, radiant in cement with a carpet and pad over a 2 r-value can cause the boiler temperature to be set  40 degree higher to make up for the carpet!! Thoughts!! Thanks PS I have talked to a few heating techs that say that pex under the slab should still heat the area fine because of how well the house is built. Thanks for any info- Peter

the sand acts as...

an insulator too... I don't get why the old wives tale w/ sand still exists. All that sand w/ the concrete the system can't respond well. You need supplemental heat at best. Maybe a control w/ a slab sensor might help but I would abandon it.

MAX temp is for your whole system

So, the two mixing valves are one each for the two slab zones? And they're set to 125? And the boiler max is set to 130?
There should be circulators on the "slab" side of the mixing valves. The mixing valve partially (or totally) hydraulically isolates the slab tubing from your system loop. It does this by partially (or totally) blocking the flow from the system into the slab, and at the same time diverting flow from the slab return, to the degree needed to produce the desired slab supply temperature. Only, without a circulator in the slab zone that would make it a "slab circuit", there's nothing to make the water flow back around (through the mixing valve) from slab return to slab supply. So there's no mixing. So, the moment that the boiler starts making water that's hotter than the mixer's setting, the mixer will throttle more and more flow from system supply to the zone, in vain effort to reach its setpoint, until the flow is virtually shut off. Voila! No flow means no heat.

Mind you, I'm going by what you said - a single circulator. If that's not correct, then this diagnosis will likely not be, either.

radiant heat loss because of pex placement?

Gorden, yes there is only 1 circulator. And yes i believe it is on the slab side. I will check tonight and try to get a picture. Yes, there are 2 taco mixing valves. Everything you have said makes perfect sense and the picture is becoming clearer that maybe an adjustment to the system (another ciculator ect) might help alot. I did have one tech that came to the home to clean the furnace tell me something about the set up looked odd, but then he went back to cleaning. Thanks for your replies, much appreciated!!!!! Peter

Yes, please post those pics

Also, please post all of the setup parameters for your boiler. We may be able to suggest simple alterations that do away with one or both of those thermostatic valves. Also, if we can be reasonably certain that your boiler won't make water that's too hot, you could temporarily set your mixing valves to full hot, which should confirm whether what I suspect is going on, is actually going on. You may not even need another circulator, if the mixing valves serve no good purpose. It all depends on the details, however. Loop lengths for all your zones (even the upstairs ones) would also be good info. The fins that you're talking about - is the tubing suspended in the joist bay with little clip-on UltraFins, or are there transfer plates that are attached directly to the subfloor? If the latter, are they thin (flashing-type) plates or the thick, extruded aluminum type?

radiant heat loss because of pex placement?

Gorden, the main floor has stapled aluminum transfer plates. They are the thinner flashing type. As far as the boiler temp output, the specs say 230 degrees at max temp. I will try to get the best pics of the boiler set up on tonight when i get home.Thanks-Peter

radiant heat loss

Gorden, the zones down stairs have 6 loops going into each zone manifold. Doing the math leaves me with roughly 6
300' loops for the den zone and 6 200' loops for the bedroom zone down stairs which is going through the taco mixing valve on the left in pics. Main floor has roughly 6 300' loops in livingroom and 4 200' loops for master bed and bath. the taco mixing valve on the right supplies heat for those. It is 1/2'' pex. The temp outside currently 12 degrees and the thermastate is set at 72 down stairs and it is 66 degrees with the mixing valve running both zones all day and loosing ground. By morning it will be 64 down stairs. The main floor seems to keep temp fine but when all zones are running there is a greater temperature swing before latter zones kick on. Gorden, i did notice last night that when my 80 gallon water heater kicked on, the mixing valve for down stairs stopped circulating and water temp was 89. 5 below this morning, upstairs 72, down stairs 66 and mixing valve struggling to circulate 105 degree water. Thanks for looking

To paraphrase Daffy Duck...

"Aha! Terminology problem!"

See, those are not mixing valves. They're injection mixing stations that have circulators built into them. So... my diagnosis would not be accurate here, as there ARE circulators on each of the slab circuits.

Here's what I see. There are two mixed circuits, one for upstairs and one for downstairs. On the upstairs mixer there are two zones, and on the downstairs mixer there are THREE zones - what's the third one?

Mixing is done via injection mixing stations. These come with their own outdoor sensors and can run their own reset curves. We'll want to come back to that. Mixed circuits are piped off of the primary loop via closely spaced tees. This is all in order, but it does have some interesting consequences. One of those consequences is that the "downstream" mixed circuits will see a lower primary loop temperature than the "upstream" mixed circuits. This is because the return from the mixed circuit is mixed back into the primary loop. In your case, the downstream mixed circuit is the downstairs one. It is critical that the boiler provide hot enough supply temperature, and enough flow, to ensure that all of the circuits receive adequate supply temperatures. So, we'll need more information about your boiler parameters, as well as the parameters for each of the RMB-1 mixing stations.

I see two black strap-on temperature sensors for the upstairs RMB-1, but I don't see any for the downstairs RMB-1. Without those, I struggle to understand how the mixing station would be able to do its job. Can you look around and see whether anything is wired to the downstairs RMB-1?

Oh, and - when your indirect comes on, your space heating SHOULD cut out. That's called DHW priority, and it's to make sure that all of the boiler capacity is available to domestic water heating. The theory is that DHW calls are relatively short in duration, and DHW priority should not result in the space cooling very much, if at all.

radiant heat loss because of pex placement?

Gorden, the third zone is our heated garage which is set at 50 and never comes on due to being well insulated and on south side. What type of perameter info do you need. pressure gauges ect???? I will look for those temp sensors for the downstairs RMB-1. I am puzzled because even though the pex is under slab, the home is extremely well insulated and 2 of the 4 walls are in the ground. Should not take much radiant heat to keep warm. Thanks for your time!!!!!

Upon closer inspection...

I think I do see those sensors. They're little and not wrapped in insulation like the other ones, so I missed them the first time around.

At this point, it's nothing obvious. Things are properly piped and appear to be properly wired, but there's no way to know for sure without checking everything out in detail. There are also a lot of parameters to consider here. (For instance, the RMB-1 could erroneously be configured for boiler protection, which is not necessary with your boiler and would likely result in too little heat being supplied to the slabs.) My hunch is that this isn't working, or is barely working, in any weather - it's just that you notice it more when it's cold. Whatever heat there is in the slab zones is likely leaking from the upstairs zones.

For giggles, wrap some pipe insulation over those two sensors (they're shiny little things with wires sticking out of them, cable-tied to the pipes - one just below the closely-spaced tees of the downstairs RMB-1, and the other on the pipe connected to its lower right port.) The RMB-1 does display all sorts of useful info about what it thinks is going on, what temperature it's trying to provide, what temperature it's actually providing etc., but you'd still need to know how to get it. Here's a link to a page with the manual, Instruction Sheet in the Documents section.

http://www.pexuniverse.com/store/product/taco-rmb-1-radiant-mixing-block

For starters, you could tell us what all the info on pages 11/12 is.

radiant heat loss

Gorden, I have written down all the info that my Taco mixing valve is doing.
i copied the pages and wrote beside each display what the my display was showing. Please note that it was 5 degrees outside at the time and the main floor zones were not running. Both the basement floor zones were running. The den was 69 and bedrooms were 67. Hope the copies are visable. Thanks for your time- Peter 

Let's try something

Adjust the boiler minimum temperature setting to as low as it will go and report what happens.

You'll want to do this on the other RMB-1 eventually, as well. Can you post the same info for both, when both are calling for heat?

re-lets try something

Gordan, (Got your name right finally) my apologies. I dropped both boiler min temp to 80. I will do the info when all zones are running. I checked my trinity manual to see if the boiler has a set boiler min temp preferance, but could not find one.Will this effect my DHW? Thanks for all your time. Peter

There's no low return temperature for your boiler

That parameter on the RMB-1 is supposed to keep plain old non-condensing boilers from getting damaged by too low system return temperatures. It is completely unnecessary for a condensing boiler. It will in no way affect your DHW.

radiant heat loss because of pex placement?

Gordan, The only difference i noticed so far since we turned the min boiler temp down to 80 is that the boiler runs alot less!!!! It was 13 degrees here in Maine this morning and all zones were off except the down stairs den which was 68 and running. I will write down the info on pages 11 and 12 when all zones are running tonight and then if all checks out, i will know the system is fine and look into pulling the carpet this summer. Thanks for taking the time to help- Peter

That sounds like an improvement...

If I'm understanding this correctly, you now have a basement zone that's getting satisfied - that would certainly be good news!

There are other parameters we can play with, but none of them would have made a difference without fixing this boiler protection snafu. It was limiting how much hot water the slab would get. Let's let things gel for a bit to see what happens once they stabilize, and then we can try to optimize some - play with reset curves, as Zman points out, or figure out why your outdoor sensor is saying it's 20 degrees when it's 5 degrees outside - that kind of stuff. Tearing up the carpet is probably a very good idea, but there's a good bit of THIS heating season left to get you through, so let's worry about that first. :-)

Don't mean to cut in here Gordan

If the outdoor sensor says it's 20 when it's actually 5 ; it's entirely possible that the wrong type of wire was used. If it's installed with anything other than a sheilded thermistor cable that may be the problem. A regular thermostat wire would get resistance (especially on a longer run) across the wire itself causing erroneous readings. Also an unsheilded cable is suseptable to interference from other electrcal wires and such.

Just my 2cents

Never mind, finished reading the post and it's already been mentoned.

Cut the radiant out....

and go to either properly sized cast iron radiators or enough baseboard that will work at the same temp. OR break open the floor and do it right.

Peter

 I really did not have time for a lengthy post, but Gordan brings some things to light that should be investigated further before beating the system up to bad.

Gordy

Tubing in sand

I won't try to diagnose your problem, but I will tell you that tubing in sand can work. Our church basement (built in the 80's) which is about 60' x 120' has 3/4" black poly tubing buried in sand  (no insulation underneath) under the concrete slab. The slab heat is currently controlled by a Taco I-Valve & it's own circulator. The tubing placement would not be a correct installation these days, but who knew back then. Some of the 3/4" poly tubing developed leaks & because of the way it was installed (60' runs side to side w/ access under benches on each side) we were able to run 1/2" Wirsbo through the poly (w/ some effort)  & make new connections on the ends. Even w/ that lack of contact to the actual concrete, the floor (covered w/ vinyl tile) heats w/ no problem & this is in Alaska.   
Your basement I believe, can be made to work just as well.
 Good luck, Dennis

efficiency

Pappa Dennis,

Its not that it will not "work". Its all about efficiency, and control. Getting the heat where it needs to be quickly, and providing the most comfort. This all equals lower energy costs.  There is plenty of evidence out there that the old way worked, but fuel was cheap back then.

Gordy

What kind of supply water temperatures...

...are you running through this?

RMB-! xblock

 Don't know how the RMB is set up. May have to go with delta t, or set point if its set up for ODR. I think there is to much lag, and lack of response for the tubing in the sand for ODR.

Gordy

Gordy

radiant heat loss because of pex placement?

Gordy, my first initial thought was X the mixing valves and pump a steady desired temp in the zones, especially the basement slab.Maybe that is an option? I am not an expert on heating as you can tell from my posts, but am not in the dark either. My carpet pad and carpet covering the downstairs 1400 sq.ft  area probably does not help any. I did the math and both are near an R-Value of 3 !!!!!. Not helping!! Thanks for your thoughts. Peter

With the correct temperature, should be OK.

Delta T would be an even less direct way to compensate for heat loss with all that mass in the way. If you look at the manual, that's really just a way to limit temperature rise in order to avoid thermal shock, so it could only result in even slower response. Setpoint wouldn't compensate at all. Outdoor reset, with an appropriate curve, should at least allow the mass to average out some sort of floating setpoint between the daily highs and lows. Should be able to get it to heat correctly if the emitter is capable.

Gordan

  Been thinking about your post. I just can not shake the notion that ODR can bring the questionable rooms to life.  It would seem that the slab would lag the response to that strategy unless it where an extended period of same weather conditions.

 But then I guess if you beat the slab with heat it will be hot when outdoor temps warm up. Still a fly wheel game.

Gordy

Raise the temp

Unfortunately your tubes are very low in the mass. This you cannot change, It does look like you have significant emitters (lots of tubing). You want to make sure your pumps are working correctly. I assume you cannot hear air in the system? What kind of Delta T are you seeing between supply and return? If this is less than 20 degrees. I would assume you have adequate flow. I think your only solution at this point is to increase the mixed temperature. You may need upwards of 160 degrees on the coldest design day to overcome the slab thickness and downward heat loss.I would manually run this temp up and observe the change in slab temp. I simple inferred gun would help greatly. 

re-raise the temp

Zman, thanks for your thoughts. My TACO mixing block has an outside temp control that is ON. I don't think i can use the DELTA-T when that is on. If nothing major shows up as far an adjustment to the system, my wife and i will pull the carpetand pad up this summer and lay stain the concrete or lay some tile. Thanks for you thoughts- Peter

Setting vs. observing

Zman didn't mean that you should use the "delta-T limiting" feature of your RMB-1, just that you should measure the return water temperature coming back to the mixing station from your slab (upper right port on the RMB-1) and calculate the difference from the supply temperature. That, and checking the floor temperature with a point-and-shoot IR thermometer, are good diagnostic steps to see what's happening with your slab and the tubing in it.

Raise the temp

Thank you Gordy for the clarification. You should be able to raise your mix design and mix max while keeping the outdoor reset active. Don't be afraid to go to the setpoint mode for troubleshooting.John Seigenthaler writes some great articles on the effect of tubing on surface temp.

Yep, all good suggestions...

But let's allow the system to stabilize a bit before making further changes. Given the mass, it will probably take a few days to figure out whether ODR setting changes are necessary. There were two things that jumped out at me when I saw that Peter had the RMB-1s, one was the possibility (as it turns out, the actuality) that he had boiler protection turned on and the other, after seeing what his RMB-1 was reporting, is what's causing it to report an outdoor temperature that's 15 degrees warmer than the actual conditions.

Once those are resolved, then I'd be inclined to tune the RMB's reset curves, and thereafter the boiler's reset curve.

radiant heat loss because of pex placement?

Gordan, we are suppose to have a cold 0-5 above zero night. I can get all the zones running and provide you with page 11and 12 info if you want. i do not know why the outdoor temp reads 15 degrees warmer than the acual temp. They are on the northside 8 ft up. underneath my main floor deck. Thanks- Peter

why the outdoor temp reads 15 degrees warmer than the acual temp

Here are a few possibilities.

1.) My boiler has an adjustment I can make to correct for what the outdoor sensor (a thermistor) thinks is the outdoor temperature and what I think is the outdoor temperature. If this is adjusted incorrectly, I could get a difference. Mine will go from -10F to + 10F. Yours may go farther.

2.) If you have a defective thermistor, or the wrong thermistor, you could get erroneous readings.

3.) If you used wire that is too long or too small (gauge), that could cause it to read lower. I do not think this would cause it to read higher.

4.) If you run the thermistor wire too close to a power line, you could get unexplicable readings.

Sensor underneath a deck? Does vent pipe run anywhere near it?

nest on outside sensor.

I just went outside and checked the sensors. I found out one of them had a birds nest built on top of it. Knocked it off and we shall see if that helps. Thanks for getting me thinking Jean-David. Thanks-Peter

Raise the temp

Thank you Gordy for the clarification. You should be able to raise your mix design and mix max while keeping the outdoor reset active. Don't be afraid to go to the setpoint mode for troubleshooting.John Seigenthaler writes some great articles on the effect of tubing on surface temp.

Ohm the sensor

It looks like you have this thing on the run. If your sensor is consistently off, you can isolate the sensor and check it with an ohm meter. This certainly could be contributing to your problem. Keep in mind the outdoor reset curve is different for every project. Taco programed a "starting point" when they shipped your mixer. It is up to the installer to "tweak" it for a particular job. 

re- OHM sensor

Zman, what sensor are you talking about? Yes, i feel like i am getting somewhere thanks to people like you, Gordan and others that have taken time out of your schedules to aid me in this dilema. (much appreciated). I think a few tweaks and pulling the carpet and i will be in good shape. My local propane company has good techs, but do not seem to have the expertise that a few of you have on this site. Thanks again-Peter

Sensor

Peter,
There is an outdoor temperature sensor hooked to each of your mixing blocks and running outside. If the sensor is giving the mixer bad data that will mess with your temps.I would start be putting an know accurate thermometer in the same area as your outdoor sensor. If you still see a 15 degree discrepancy,  I would then disconnect the sensor from the mixer and then check the ohms between the 2 wires. The manufacture can tell you what resistance you should be reading at a given temp. I think the possibility of AC power interference mentioned here is valid. removing the sensor and testing it individually will eliminate this. Keep in mind that handling the sensor will  warm it up and change the output temp.
Carl

adjusrments

I posted some operating temps of both floors when all zones were running. Take a look at what i wrote on sunday and let me know if you would make any adjustments to basement mixing block. Thanks- Peter

adjustments to mixing blocks

Zman or Gorden, I am posting photos of the results of all zones running when the temp out is -14, Brrrr. Note that upstairs is being met just fine, and down stairs temp was 64. Please advise on any ajustments i can do to the mixing block menu. Thanks-Peter

Let's try this

On the upstairs zone, change design mixing supply to 130 and max mixing supply to 135. Yes, we're actually dropping it a bit, since it's keeping up at lower temperatures. The reason for this is that we don't want it to be too greedy and steal more hot water from the boiler loop than it actually needs (leading to quicker zone satisfaction upstairs but more lag downstairs, which is the one with a problem.)

On the downstairs zone, change design mixing supply to 140 and max mixing supply to 145.

On the BOILER, change the HI setting to 150 and the RES setting to 85. (See section 8.0 - Sentry 2100T Controller - of the attached manual.) What are they at now? How does the boiler outdoor temp sensor read, compared to the ones at the mixers?

re let's try this

Gordan, thanks for getting back to me. I will reset those settings and let you know what the boiler info read before i adjusted them. Thanks again-Peter

Please post the new readouts from the mixers

...after you change the parameters and the system's been running awhile, all zones calling.

radiant heat

i don,t  know if any one has asked this question but what is the setting of the trinity boiler hot water supply?  is it set as a low temp condensing boiler setting of 130 or so, or is  it at a 1 80 or so boiler loop temp. my thinking is if it is set a  130 or so temp then the Rmb  will not have enough for the mix even at full speed.

Re paul

I am checking the temp on the boiler. I have to figure out the function and menu operation first. I am not a boiler tech, so i did not dare to mess with the boiler menu last night. Maybe in a day or so!!!! Thanks for your post-Peter

It's in the manual I attached

The "HI" and "RES" settings jointly determine the outdoor reset operation. The boiler will produce "HI" at 0 F and below, and "RES" at "RES" F and above. Judging by what your mixers are sensing, "HI" is 130 F right now.

The "LO" setting is for your indirect.

Attached manual

Gordan, i have that manual at home. I went to change the boiler temp on the HI to 150 and The RES to 85 like you said, but did not feel confident enough to make changes to the boiler. If it were summer i would not worry so much, but being january, i really need the furnace running. I'm sure it is an easy adjustment. Thanks-Peter

I understand your reticence

Though, really, it's no different than tinkering with the mixing station parameters. (And the latter, at this point, won't do much good without warmer water from the boiler.)

Anyway, whenever you muster the gumption to do it, please be sure to report your results and post what the mixing stations are saying!

Boiler readings

Ok Gordan, I came home and figured out how to read the boiler settings. I am a little puzzled at the temp settings but here it goes
Hi- 190      Lo- 153       Diff.- 20      Res.- 80
SF5-82    HF5- 240     LF5- 45  ER5-  ON
I did not see an outdoor setting temp. Hope this helps. Thanks so very much for you time and expertise!!! Peter

Check everything

I got to thinking on this. What kind of lunatic puts mixing blocks on a modcon boiler that already has outdoor reset? Both floors should be able to run at the same temp directly off the boiler. The boiler never fires hotter than it needs to and runs at optimal efficiency.Those mixing blocks are $1,000 bucks each!
 That being said I think you need to check everything. It looks like you have 1" main lines. That seems small for a 199K BTU boiler is the boiler a 200? What size is the boiler pump and what speed is it on? Are those 1/2" lines going into the blocks? Are the block sensors strapped to the correct pipe. Start  feeling the pipes. Are the pipe attached to the lower (undersized) headers at the same temp?
Your symptom is cold floors, the pex placement is not helping. There is something else going on.With those boiler settings you should be able to get the temp up. Is the boiler really getting that  hot? Does it have a gauge?

re-check everything

Zman, My boiler is a Trinity 200 propane on the wall as you can see in the pics. The copper piping from boiler to mixing blocks and manifolds are atleast 1''. Pex tubing in the floor are 1/2''. My floors are not cold, the upstairs zones are warm and being supplied fine. The downstairs concrete is warm at times and the area temp is met most of the time until colder weather but the down stairs zones hardly EVER shut off. The water temp is always mixing around 110-120 for down stairs zone. I think if it were running at a constant 130-140 plus take up the carpet and pad, it would be 90% better. The sensor straps seem to be on the right pipe and the boiler temp gauge last night was running around 167 at times with just the down stairs zones running, but the mixing block was only putting 110-120 degree water into the slab. Everything seems to check out. Thanks for the input- Peter

Good

OK Good,
That eliminates some potential bottlenecks. I assume the out put to the lower level does not change regardless of what the upper level is doing.(the upper zone is not stealing all the heat) ?
Are you comfortable that the zone controller is set for the higher temp, and you are not getting it?
What I am saying is if you have good flow and high temp in the main pipe going past the  mixing block and you can't get the mixing block to inject that heat into the radiant loop,  it may be time to call taco and get some tech support. You may have a issue with the block

Piped backwards

It looks like the mixing blocks are piped backwards. If this is the case they are reusing much of the water they are supposed to be sending back to the boiler. I think this is the entire problem. Check the manual and the direction arrow on the main pump

re-piped backwards

Zman, the mixing blocks are correct in there water flow. The hottest water is pumped out the bottom of the block and returns into the top. In a normal case radiant heat scenario, the concrete slab in the bottom floor would run 85-100 degrees and aluminum finned under the floor would run 130-150, so the mixing blocks would be the ideal setting. Where my pex tubing is under the slab and carpet on top of the slab, the previous home owner(builder) could have ran a straight 130 degrees into the pex on both floors and eliminated the mixing blocks. Maybe some day that may be an option for me, but i do not want to jump ship just yet. thanks for your time and input-Peter

Backward

Take a close look at page 2 and 15 of the manual. Then look at the arrow stamped on the grudfos pump. I am certain they are backwards. I live in house with tubing place to deep and with inadequate insulation underneath. I do have the correct carpet padding. I need 130 degree water on the cold design day to make it work. I have also done the the calcs in the textbooks and come to the same conclusion.

Arrow on the casting

It is possible they turned the motor when they installed the pump. if it is pointed down you are OK if it is up it is incorrect

re-arrow on casting

Zman, i will check the arrow on pump tonight. Thanks

It's unlikely

If the boiler temp sensors on the mixing stations are to be believed, the one for the downstairs zone is cooler than the one for the upstairs zone, suggesting that the circ is upstream of the mixing stations.

But, then, the upstream mixing station is also reporting 129 F as the boiler loop temp downstream of the mixer, which is just about impossible if the boiler is making 190.

Panman, this is not going to go anywhere unless you become a lot more comfortable with checking things, and follow the suggestions of those who are trying to help you. That means getting a contact thermometer and taking water temperature measurements already... it also means changing the mixer parameters as I suggested, and it also means checking out whether your outdoor sensors are good or busted. If that sounds like a bit much, and I'm not suggesting that it shouldn't be, you really need to get someone on site to fix this for you. It's not impossible to diagnose remotely, but it requires a reliable and capable set of remote hands and eyes. You've got a system with a lot of moving parts, and we're not getting very far nailing some of them down.

re-it's unlikely

Gordan, If i understand your message, you see something wrong with the systems flow of 190 degree boiler water? Gordan, what would be wrong with by passing the mixing blocks down the road and have 130-140 degree water flow through all the zones calling for heat? Thanks for all your help. I will seek to get someone on site. You have been so very gracious in helping. Thanks-Peter

I would think that 190 would be higher than necessary

But no, what I'm getting at is that I don't believe that the boiler is making anywhere near that high a temperature. Based on the readouts you provided of the mixing station sensors, I think it's making 130 or so. You should be able to read it out from the boiler's display (water temp light is lit, should be showing the temperature in the display); you should also be able to read out the sensed outdoor temperature (air light is lit.) If the boiler doesn't automatically cycle between displaying these values, you may need to hit the up or down arrow keys until the correct light is lit.

You should also be able to confirm it with a contact thermometer, by touching piping at appropriate points (boiler supply outlet, return outlet.) A simple digital kitchen thermometer that you can get at your grocery store for twenty bucks, and then use to make sure that you're not overcooking your roast, would be plenty good. Better than going blind, for sure.

There's nothing wrong with bypassing the mixing blocks once your boiler is set correctly. You can't just pull them out, but have to replace them with circulators, properly piped and wired through relays. Not much work for a pro.

190 degree water

Gordan, the boiler water was jumping between 160-170 when heating my DHW a few days ago. I have a co-worker that has a temp gun that will get me a close estimate. What boiler efficiancy would i lose if the system was set up to pump 130-140 degree water into the zones without the mixing blocks. In my case of needing closely the same temp for upstairs and down, i fail to see the need for mixing blocks. Would the boiler keep up? Would YOU eliminate the blocks if it were your system?PS, my circulator is set on med. setting!!!  Thanks for your thoughts-Peter

So we just need to know what it's showing during space heating

You wouldn't lose any efficiency by eliminating unnecessary mixing - you would gain efficiency, and lose unnecessary complexity(and potential sources of breakdowns and - once things break down - of difficulties in troubleshooting. As we have seen. :-)

BUT - and this is a big but - even though they may not be necessary in your system, I don't think they're the source of your problem - or at least not the sole source. They may not be optimal but they shouldn't stop the system from heating properly. What I've been trying to do is get your system to a working state without major surgery, so at least you're comfortable, and then leave you with some suggestions for improvements based on what we find out.

When you get that thermometer, measure at the following points (while everything is running):

- outdoor temperature (point at some object close to where your outdoor air sensors are, but not the house itself)
- piping exiting the boiler that goes to the red circulator (hopefully the supply)
- the other pipe exiting the boiler (hopefully the return)
- boiler loop piping on either side of each of the two mixing stations' closely spaced tees
- all four pipes going into each of the two mixing stations
- the exhaust flue pipe on the boiler (the hot one)

Now, if you're using a point-and-shoot thermometer, wrap a couple of inches of the pipe in black electrical tape and shoot it from up close, or you won't get a good reading. That's a total of sixteen measurements and it should be taken in close sequence (so, put the tape on first and then take all the measurements.)

You also need to check what the boiler is reporting as the water temperature and the (outdoor) air temperature.


In addition, sample the floor temperature at multiple locations in the downstairs rooms and post those as well.

Believe me, those measurements should tell us a lot about what's really going on.

Re-heat temp gun

Gordan, I will try to get all the info that you wrote down. thanks for being so thorough. Thanks - Peter

Gordan- heat gun results

Ok, Gordan, here we go!!! The maine temp at the time of the reading was 19 The gun results were 14 as you can see.The mixing blocks outside temps were 25. The boiler was telling me that the water temp was 170 at the time of the reading. With all the zones open the mixing blocks were not above 115-120. The results of the info are on the photo. PS- The electrical tape does make a good 10 degree difference!!!!!! Thanks -Peter

Two things jump out

1. If the boiler's sensing 170 degrees (this would seem to support the HI setting, as well) and actually producing 125 degrees, there's something wrong with the boiler. The sensor could be broken (there's information on how to test it in the manual) or there could be local hot spots where the sensor is located, owing to restricted flow inside the heat exchanger (this depends on whether the supply sensor is in the exchanger or on piping.)
2. The exhaust temperature seems too high for the return water temperature. This could also be due to there being something up with the heat exchanger, or inadequate flow.

What's the model of the red circulator? Does it have a speed selector on it? What speed is it on?

re-two things jump out

The circulator is a groundfos. It is set on med. Thanks peter

Which one?

Of course it is a grundfos. Is it a 15-58 or 26-99? Which way is the arrow stamped on the pump pointing?Is the the pipe size 1" or 11/4". You are positive the the boiler is a 200. Not a 150 or 100?The look the same from the outside. This is really important with a high head boiler. 

re-which one

Zman, The arrow on the circulator is pointing down. All the boiler manuals that came with the boiler say it is a 200, but i can check if you give me something to look for on the boiler to clerify that it is a 200!!!!! As far as the groundfos model # and pipe size, i will check tonight. Thanks-Peter

input btu

There will be a model number as well as the input btu plate somewhere on the boiler. Modcons can be fickle about flows. I am trying to rule this one out.

Yeah...

On this one, the boiler temp sensor is tapped directly into the top of the heat exchanger jacket, off to the side. Inadequate flow (due to either underpumping or blockage on the water side of things) could conceivably create a hot spot near the sensor, causing it to read much higher than the actual supply coming out of the water. At least that's my mind's eye's view...

Grundfos makes many circulators

Hopefully yours is an UPS 26-99FC. Can you confirm?

Also, are you absolutely sure that what you were reading off the boiler display was the temperature? Was the left-most LED indicator under the display on when you were reading off the value? If it was the third one from the left, you were actually reading gas input.

Please confirm those two things. Then, do the following test. During space heating, once boiler temperature stabilizes (not bouncing around much - use your IR gun to measure boiler supply and boiler return) then take down the boiler supply, boiler return, and flue temperatures. Then kick the circulator to high speed, wait until things stabilize again, and take another set of supply/return/flue measurements. Also watch what temperature the boiler is reporting on its display, both before and after the speed change, and post that too. Make sure that you're taking down the boiler water temperature and not something else.

You haven't told me what outdoor air temperature your boiler is reporting, compared to an IR gun reading. This is important. The second-from-left LED under the display will be lit when the outdoor temp is being displayed.

re-groundfos

Gordan, i am sure the water temp was 170, because the light was bouncing back and forth from water temp to gas temp. The gas temp went much higher, sometimes in the mid to high 200's. I do not have an outdoor temp on the boiler. The light on that setting never lights up and when i go into the function mode, nothing comes up on the screen plus there is nothing outside anywhere on my house to indicate there is a sensor hooked up. Thanks-peter

I was going to ask you about the gas reading...

I didn't want to muddy the waters. If that reading is in the 200s, then basically the boiler is giving it its all and simply unable to keep up. According to the manual, the Ti200 gas input display goes from 40 (meaning lowest input) to 240 (meaning highest input - 200,000 BTU/hr.)

One thing I would still like to be able to explain is why it's saying it's making 170 degree water when all other indications point to much lower.

If the boiler is truly on full tilt all the time, and still not able to keep up, then you're probably wasting your money heating the soil under the house, in which case you'd be better off spending the money that you'd have put into ripping up the carpet and etching the concrete, on some radiators or baseboard instead. But still do that test that I asked you to do above, with increasing the flow. Use your hand to confirm, too, but carefully... the difference between what 125 F feels like and what 170 F feels like is pretty startling.

Isolate the boiler

Let's find out what is up with the boiler.Turn off the mixing blocks and see if the boiler will come to temp.Both on its own gauge and with your measurement tool. If the boiler won't come up let's figure it out. Is the pump correct? Is the piping correct? Sensor error? Call tech support if needed but get the boiler working.There is no point in messing with mixing blocks until you know that you are are giving them enough heat.
If the boiler is in fact a 200,000 btu, There is no way that a small radiant slab is dragging it down 40+ degrees. The mixing block would have to be pumping over 10 gpm through a few 1/2" tubes.
I see the sequence as
Get the boiler working at a high temp (170 or more)
Get the lower level mixing block putting out a higher temp (150)
Balance the boiler and mixing block for optimal efficiency

re-isolate boiler

Zman, Like i told Gordan- the circulator is a 15-58 with 1'' pipe. I agree with you that i need to find out why the boiler is saying 170 and the outlet is only reading 125 and mixing block inlet pipes 90-100. I need to get a tech into look at the boile. I do have some great info to help them along. Thanks Zman-Peter

re-groundfos

Gordan, my circulator is a groundfos 15-58 with a 1'' pipe. I put the circulator on high and both the boiler out and the return went up 5 degrees. The funny thing is that it is 20 degrees outside and my basement zones were satisfied this morning. I will have to get a tech in and find out why the temp of boiler is not the same as outlet. Thanks a bunch

UPS 15-58

So... that circulator is "smaller" than what your boiler install manual recommends. It would not be able to flow anywhere near the recommended minimum of 8 gpm through the boiler and the piping on medium speed, probably only half of what it's flowing on high speed. The result is that, when the boiler is firing at or near full tilt, there could be big differences in water temperature at different spots in the heat exchanger. (For instance, where the sensor is located.) This could explain the difference in sensed vs. actual water temperature. The ability of the heat exchanger to transfer heat from the flame to the water would also be severely compromised, which could explain high flue temperatures. Did you take new measurements once you kicked the circ to high speed? What temperature was the boiler showing, versus the temperature of the boiler supply pipe? What was the flue temperature?

Is the pipe 1" all the way around? It looks from the pictures like it's smaller near the boiler, but that might just be a trick of the eye.

re- UPS 15-58

Gordan, there is 1'' pipe out of the boiler and out of the circulator then goes to 3/4'' at the T's before going to the mixing blocks, i will double check measurments of pipe on the entire system tonight and heat on the boiler when circulator on high. Thanks so much for your continuing input. Your knowledge is much appreciated-Peter

re-ups 15-58

Gordan, i have some good news and bad news. Bad news 1st. I took the serial # and model number off the boiler and it is a Ti150 NOT the 200. Good news is that when i turned the pump to high, the boiler temp dropped to around 140-150 and my basement mixing block went to a steady 135 degrees and the both zones down stairs were met in a matter of few hours!!!! YAY. FINALLY the root of the problem.i did not have the temp gun with me. I will eventually change the circulator to the 26-64 that the book recomends for the 150 but for now that is a great improvement. Gordan, if i ever have a problem with 1 or both of the mixing blocks, is the ti 150 boiler capable setting a DHW temp and radiant water temp so i can illiminate the blocks and straight pipe it???????? Gordan i think your work here is done!! I have learned alot about my boiler and the parimeters thanks to you and a few others. Thanks Peter

Phew...

Finally we're getting somewhere! :-) See how getting some data helps us quickly pinpoint where the problem may lie?
 
What was the outdoor temperature last night? If it wasn't as cold as it gets, you could still have problems keeping up when temperatures dip further down. If you can get your hands on the thermometer again, you should take a fresh set of measurements (the full set of 16) and post them here so we can see what's going on now.
 
To answer one of your questions, the boiler can do what you're asking but you need to get, and install, an outdoor sensor for it. Judging by the manual, you COULD use the sensor from one of the RMB-1s as they seem compatible. Or you could just buy this: http://bostonheatingsupply.com/81027-1.aspx

You can reuse the wiring that's currently going out to the RMB-1 outdoor sensors and mount this in the place of one of them. Then you would set the outdoor curve using a combination of HI and RES settings on the boiler.

If this were mine to redo, I'd combine the upstairs and downstairs circuit to one. Then I'd put in a Grundfos Alpha, which is a much more efficient circulator than the ones you've got, to circulate water through all the zones. It can detect zone valves opening and closing and adjust its flow accordingly. You may not need a different circulator on the boiler circuit; measurements will tell. What you DO need is for a qualified guy to come in on an annual basis and check everything over, clean the heat exchanger, perform combustion analysis, and adjust anything that needs to be adjusted.

question

Gordan,Got a question. I now have 2 taco mixing blocks, 1 for 2 zones down stairs and 1 for the 2 zones upstairs. In the future rather than pay $1000 to replace one of them, you recomemded replacing them both with 1 grundfos alpha  to do all 4 zone on 1 circuit.(1) will the grundfos pump a constant 140 degree water no matter how many zones are calling?(2) Can it push the water as fast as the 2 mixing blocks when needed to fulfill demand on all 4 zones? (3) Do i still need the head circulator or can i put it in the place of it? Thanks for any info. P.s. System has been meeting the supply down stairs unless it goes down to 0. Much better than before. Thanks-Peter

Yes

I believe Gordon's recommendation is "spot on". Yes the grundfos alpha can easily handle the load. It may take a bit of trial and error to get it dialed in.

re-yes

Zman, thanks for the input. I was looking for some info as to my questions. You answered the load question, can you elaborate on the other 2. Thanks -Peter

The rest of the answer

The boiler can be set up to manage the outdoor reset.The actual output temperature of the boiler will be what is calculated for the heating load just as the mixing blocks are doing now. The (secondary) heating loop with the alpha circulator will tie into the main boiler loop using closely spaced tees or another "hydrolic separating" method, similar to the way the mixing blocks are now.. You will still need your primary boiler circulator. I am not sure whether the primary boiler pump needs to be upsized. It sounds like it is smaller than spec, but is working.That boiler is designed for more of a high head circulator.The safe move would be to replace it.This approach should allow the boiler to run more efficiently and reduce your pumps from 5 to 2, saving quite a bit of electricity

re-rest of answer

Zman, Thanks for such a quick response. Makes sense now. Just looking ahead to better the system. Can my boiler be set pump out 140-150 degree water to the 1-4 zones with out all the outdoor re-set and goolash, another words when thermostate calls for heat, the zone has 140 degree water going through it until zone is satisfied? Just wondering. Thanks a bunch-Peter

Yes

Your boiler can produce the same heating curves your blocks presently do. You might decide you need 150 on the coldest day and 100 on the warmest. Your boiler will start condensing and approaching peak efficiency if you can return water that is cooler than about 130 degrees. It is not a big deal if you don't condense on the coldest day, but ideally your boiler curve will allow condensation on your "typical" heating day.Check out this Ashrea presentation and you will see what I mean www.pugetsoundashrae.org/PDF.../AshraeCondensingtechnology.ppt

Outdoor reset is better

Peter, it's not just a matter of efficiency, but also of comfort. If you've got nothing but a thermostat controlling a high-mass emitter such as the slab, you can expect a lot of under- and over-shooting of the temperature in those zones. By the time the thermostat falls below its setpoint, the slab will have cooled enough that it will take a while for it to warm up to the point where it's once again meeting the setpoint, and by the time that happens (and the thermostat cuts the flow to that zone) the slab will have warmed enough that it will continue to release heat long after the zone is satisfied. It's possible that a very intelligent thermostat (with a PID control, for instance) could anticipate and prevent the temperature variation, but you'd be far better off with near-constant circulation and outdoor reset (where the large mass is kept at or near the optimal temperature so that it keeps up with heat loss.)

re-outside of the system

Thanks Gorden, the system is doing much better. The downstairs is meeting the heating need and shutting off alot more than before i got on to this website. Thanks for your help. My wife and i are still mulling the fact of removing the carpet and tiling in the near future. Thanks so much-Peter

Narrow it down

I have to agree with Gordon.You have to narrow down your problem. You have to know for sure that you have good flow in the correct direction and adequate supply temp. Never assume that because you "believe" the water is going the right way, that it is. By the same token, just because one gauge in one location is indicating a certain temp that the whole system is that temp. Measure it! Once you are absolutely positive that  you have flow and temp then start looking at the mixing blocks. I think 190 degree water for troubleshooting is fine. Eventually I would like to see either no mixing blocks or a boiler curve set slightly above the highest temp block curve. Unless you can get into this troubleshooting mind set you are going to continue chasing your tail.

outside of the radiant system

Gordan is doing a great job walking through the radiant with you... I won't go there and interfere, but keep on with him, he's bringing you to where you want to be with what you have as far as settings and like goes. Nice work Gordan!

but a couple of other questions, just in case. I'm suspicious about this drop to an apparently constant 64 degree room temp at any temp under a somewhat predictable outdoor temperature threshold:

1. what are you normally maintaining for a room temp in the basement area before it drops to 64?
2. do you have any air equipment in the house? Say, like an HRV/ERV? if so, specifically what, and is anything dedicated to the basement or primarily directed at the basement?

re-outside of the system

NRT_Rob, I want to clerify the 64 degree drop is a gradual drop as the temps get colder. The room is set at 72. Between 10-30 degrees the down stair zones are running all the time and do not get the room to 72. When temps are 10 to -20, the system down stairs can't keep up and temps have dropped to 64. We have no air equipment in the home. Thanks for your input. I will know more tonight when i get all of the system temps as Gordan has stated. Thanks