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Joined on October 13, 2004

Last Post on April 13, 2014

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Starting at the finish line

@ March 19, 2014 6:40 PM in Please critique this design

I will reiterate what others have said.

Do a room by room heat loss.

Determine existing base board out put at what water temps you wish to use to be condensing.

It is possible you may have base board enough to lower the supply temps if envelope upgrades have been made to the structure after the original heating design was installed.

Or you may fall short with what is existing, and have to add more, or sacrifice a higher supply temp if that is not possible.

Remember also with ODR your not going to need high water temps most of the heating season even if your base board is just enough at design conditions. So at design you might sacrifice efficiency with out condensing, but be condensing at warmer temps.

But you don't know any of this with out the heat loss, and emitter outputs start with that.

I would not ditch the TRVs either.

Urethane injection

@ March 19, 2014 5:13 PM in Has a sink hole ever tried to swallow up a boiler you service?

Nope. Is this a company that mud jacks professionally or someone's idea to try? Never heard of it but that does not mean it's something new. Maybe it will float. I think it will deteriorate over time in that environment.

If it's still settling they have that problem to solve first!
Injecting what ever is still going to settle unless the source that's causing this is found and fixed.

Hot Rod

@ March 16, 2014 4:26 PM in Delta p vs delta t

like 👍

Creating like button of my own.

I agree with the fact we tend to be absurd about trying to control delta T.

Thermal equilibrium, and hydraulic yes.

Mud jacking

@ March 16, 2014 11:12 AM in Has a sink hole ever tried to swallow up a boiler you service?

Depending on the experience I think I would disconnect associated piping before they mud jack. Seen mud jacking go perfectly, and seen them get more then they wanted. Hopefully they are just filling the void. Or you might be repiping your beautiful work.

Fire tube

@ March 15, 2014 8:48 PM in Mod/Con Heat Exchanger Designs

Stick with that.

From there it's about what's available in your area for parts, service etc.

Which brand comes in closest to heat loss calc.

Comtrols ring in there to. You may not need all the bells, and whistles so that's consideration.

Don't forget HTP elite ft.


@ March 15, 2014 11:47 AM in Confused about "pumping away" and Knight WH installation

I agree with you. I was thinking wbn.

Look at the schematics for wbn verses whn

The wbn is p/s with x tank in the heating loop. Whn is
Identical schematic eliminating p/s. Hmmm seems that ponpc may be variable depending on how many zones are calling no.

per diagram

@ March 14, 2014 5:11 PM in Confused about "pumping away" and Knight WH installation

Are you using zone valves?

Are you piping with differential bypass as suggested?

IF yes to both then the primary loop will be pumping away from the PONPC

You are pumping away

@ March 14, 2014 3:50 PM in Confused about "pumping away" and Knight WH installation

The air separator is getting the hottest water for better air removal. That's why it's in its location in the diagram. They want you to pump into the boiler.

Vacation homes

@ March 12, 2014 8:51 PM in Legionnaire's found in heating system

Just thinking it cold supply stagnant in pipes for a period of time could see those temps in the summer Bob.

Cold water side

@ March 12, 2014 7:32 PM in Legionnaire's found in heating system

We always worry about the critters on the DHW side. But they do exist in lower numbers on the cold supply side. Maybe in lower counts depending on usage, idle temps (summer time elevated temps). So for the people with vacation homes that could be an issue. So how does one purge the critters on the cold side of domestic water supply?

I also wonder about protection all the way to the shower valve. If you mix down at the water heater that leaves a trail of pipe with lower temps to breed in.

Bypass ball valve?

@ March 12, 2014 7:10 PM in Pumping away ? I must have something messed up! Help

You mean for the fill supply valve?

And you mean pressure reducing valve set to 12 psi.

Did you check x tank pressure isolated from the system?

Glad problem is resolved.

Circs pressure differential

@ March 9, 2014 12:40 PM in Pumping away ? I must have something messed up! Help

Will depend on the head the pumps sees. The larger the head loss the greater the differential pressure. If you install a 0-30 psi pressure gauge at the circs inlet, and outlet locations you could use the psi difference to calculate feet of head by taking the psi difference multiplied by 2.31 this gives feet of head.

Example if the psi difference is 5 psi then the feet of head conversion would be 11.55 feet of head loss.

As far as your primary, or boiler loop there is enough calculable information you can see to find the loops head and plot on the 011 pump curve chart.

As far as the system side is the 20 units of base board in multiple floors, or is it a one floor layout?

So if the inlet side of the circ drops to 11psi the fill valve will start filling the system for as long as the pump is running. But once the relief valve pops the pressure when you shut everything off should be higher than 12 psi. Since the relief dribbles at 30 I would think you would be in the 20 ish psi range until you bleed off some fill water back to 12 psi.

One of the possible issues with the pump on the return pumping into the boiler is the added differential pressure can pop the relief valve, but usually this happens when the system pressure needs to be higher because of system elevation to get psi over the top.

So in your case the 011 would have to add 18 psi to the outlet side to pop the relief valve on the boiler.

pressure reucing valve

@ March 8, 2014 12:26 PM in Pumping away ? I must have something messed up! Help

I think Ice may be on to it. Quite possible the circ differential is making the fill valve dump into the system.......unless the make up water is off.

One other thing is x tank pressure properly set?

Circ orientation

@ March 8, 2014 11:24 AM in Pumping away ? I must have something messed up! Help

Are you sure all circulators are pumping in the right direction?

Awesome statistics

@ March 7, 2014 8:45 PM in Recently Completed Radiant Job

That is beautiful. Tubing is cheap keep the spacing tighter. I like that concept, keeps water temps low, and temps even.


@ March 7, 2014 7:50 PM in Heat loss through rim joist

The installation guide clearly states that you can put an 1 1/2" hole anywhere in the WEB and not in the hatched area over a bearing wall. As soon as you go to a 2" hole you must be no closer than 1' from the FACE of a bearing wall. Clearly what the OP wants to do is not except able per TJI install instructions. PERIOD

TJI or BCI are very vulnerable when you start carving out the web over bearing points. The holes the op wants to elongate are in the bearing area of the joist.


@ March 7, 2014 6:17 AM in Heat loss through rim joist

Read documentation for TJI before you do anything here is the link.

You can drill an 1 1/2" hole about anywhere just below the bottom of the top flange, but not 2" , nor elongation of hole. You should be 1' 6" from bearing point face of wall.

If anything consult factory rep with your question before doing anything.

Here's one benchmark article.

@ March 5, 2014 7:10 PM in Fuel use question?

The census was in 1997 but it gives you an idea. I would suspect those percentages have changed for the better 16 years since then.

This explains it well.... Good site

@ March 5, 2014 6:16 AM in Unequal circulators in series

Praying on the housing market

@ March 4, 2014 5:12 PM in Help!! staple-up insulation foil myth

Plummer is right. Next they will want window replacements. Triple glazed krypton filled please.

Thermal shock

@ March 4, 2014 12:04 AM in Help!! staple-up insulation foil myth

Not over my head. Depends on how your system is set up. Staple up is what you have. What temps are you supplying? Is it zoned? Usually it happens when a certain zone is turned down to bare bones and the boiler is up to temp maybe coming off a call from another zone. Boiler is hot cold zone calls, and bingo bypass piping only helps a little.
So the boiler can be a cold start boiler, and still get thermal shock in certain scenarios

If your boiler is suffering from excessive condensing then there will be metal flakes in the pan below the burners, and on the burner tubes. Don't know your service regime annually or otherwise. Has it been serviced periodically?

If your boiler is plumbed according to WM I/O manual then point that out to the buyer, and inspector. If not they may have a point.

I will say

@ March 3, 2014 6:49 PM in Help!! staple-up insulation foil myth

That this home inspector is being thorough good for the buyer.

Last year a friend of mine bought a log home with all kinds of trouble......and had a home inspection for 400 bucks. When i asked what the home inspector said about the issues in all facets plumbing, structural, electrical .... My friend said all the inspector said is this house will be a lot of work.

About the low boiler return temp boiler shock would be what the inspector may suspect. If in deed there has been thermal stress over the last 10 years it would be leaking by now.

Simple boiler bypass does not always guarantee protection through out a heat call.

I have a WM Cgm 7 that's been drinking 95* return water from my radiant for 21 years simple boiler bypass installed.. Reasons of survival rate can be attributed to a generously oversized boiler. But as far as condensing its a non issue as boiler is always above 135 after heat call.

Incidentally I have been hoping this thing would die so I can mod/con it. I hate pulling a perfectly good unit out to install a new one. That's why I have not worried about the return temp for the last 13 years I have had possession of the castle. Alias it lives on.
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