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Joined on January 19, 2012

Last Post on April 19, 2014

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@ March 27, 2014 1:06 AM in Coming From the"High"Country CO...(Altitude not Attitude:-)

What in the world are you talking about?
The difference in pressure between  sea level and 10,000 feet (where I am sitting right now) is a little less than 5 PSI. If a diver goes down 33 feet underwater they have doubled the atmospheric pressure.

As you go to higher altitudes combustion generally works just fine. You just have to change the air/fuel mixture and derate the appliance, as Mark pointed out.

What Richard is trying to figure out is whether a specific boiler has been proven at a higher altitude than the manufacture specs. I honestly don't know but understand where he is heading. Some mod/cons take on some weird characteristics when the air gets to thin.They get strange harmonic hums and cannot be tuned for peak efficiency. You really don't want to be the first guy to try and figure out the maximum operating altitude of a new product.

As a side note, the climbers at 18k feet cook food just fine. The water boils just fine, it is just at a much lower temp and it takes the food longer to cook.The burner also produces less BTU's than it does at sea level. I have never heard that if you don't heat the food enough, the vitamins won't come out. What temp do you cook you salads at?

As for the plane depressurizing, I think the people would be screaming hard enough so that the the lungs would not buld pressure and rupture.

I wonder if Carol Fey at Viessmann would be of any help. I would think she has a solid understanding of altitude.If tests were done in Leadville she may be able to access them.



@ March 26, 2014 12:14 AM in No steam reaches shut off valves.

I looks like someone has employed a control strategy that uses both the pressuretrol (the gray box above the gauge) and an aquastat  on the return line (silver box under the main vent).
If you can draw the way these are wired in relation to the "switch", you will get better answers. What you have is not standard. Close up pictures of those devices would also help.
I would highly recommend purchasing all of Dan's steam heating books from the "shop" tab. You are dealing with some very cool and very old technology, you will learn tons from the books.
As a side note, you will get the attention of the true steam gurus if you post under "strictly steam"

Blow off

@ March 25, 2014 11:50 PM in boiler blow off

Does it happen with the fill valve isolated?
Do you have an indirect tank or coil that could be leaking high pressure domestic water into the system.
Is the expansion tank sized correctly?
Did you check the tank pressure when it was detached from the system?
A picture of the piping arrangement would help.


@ March 25, 2014 11:35 PM in Old Wirsbo Maifold - retire line and cap

As far as the zone valve goes, you can either leave it or unscrew and remove the head. You don't want to remove the valve itself.
The tubing is going into a compression fitting. A pipe cap will not match up. You might be better off capping the PEX.


@ March 25, 2014 11:25 PM in Radiant Wall - Ceiling -Floor Assistance

Go to this link and download CDAM.
A great source.

I see

@ March 18, 2014 11:11 PM in How would you do this?

This is a good conversation.
Some of the difference may be the water. In Colorado the indirects hold up pretty well. I have seen some really plugged up tankless units.
The tankless units get derated pretty far for altitude and the water coming out of the ground is really cold. That makes for an uphill battle.
We also have a very long heating season so the boiler is already hot.
Love your posts,


@ March 18, 2014 11:00 PM in Piping a Wallhung Modcom for concrete radiant.

That drawing will work well.
Be sure that the closely spaced tee are just as drawn in a straight piece of pipe.
There is no hard fast rule about the expansion tank and air separator location.
That boiler will do a nice job of purging any air that runs though it. I has a design that slows the water that passes though. It also has an air vent on top.
I would put the a micro bubble separator on the secondary as drawn. It is important that the circulators are "pumping away" from the expansion tank. In the drawing all of them are. I like that the expansion tank is closest to the circulator that is doing the most work and generating the greatest pressure differential.
The exact location of pump B is not critical. It is better to have a straight pipe on the intake side.

Good stuff

@ March 18, 2014 6:24 PM in Piping a Wallhung Modcom for concrete radiant.

I would check the PH of the glycol before connecting the boiler. The newer indirects are going to have higher flow rates. I would run 1" for the future.


@ March 18, 2014 5:30 PM in Piping a Wallhung Modcom for concrete radiant.

Looks like you are off to a great start.
Your existing boiler is approx 80% efficient and because it is atmospheric should be derated 4% per 1000 above sea level. 186 x. 80 x .73 = 108.6k/btu output.
The new boiler is about 90% efficient and only derates 2% per thousand. 110 x .9 x .865 = 85.6k/btu. Unless your old boiler ran 24/7, I think you "dun good"
The tubing spacing and lengths are great. The slab and building insulation are also great.
The recommended drawings in manual seem like a perfect fit for your house.
Alpha pumps work really well in radiant systems. Without checking the math, it looks like a fit. You would not need the bipass with the alpha.
15-58 for the other circs will work well.
You will want to use the outdoor reset feature in order to reduce overshoot and increase efficiency. I think you will be blown away at how low you can turn down the water temps.
If the amtrol is original, I would toss it sooner than later. The heat exchangers in those units are not very robust and they have a habit of springing leaks.
Does your garage have a drain for condensate?
Do you pics of the existing manifold?
The tubing is Hepex not aquapex? Folks had trouble with that for a while.

Thermal imaging

@ March 18, 2014 2:14 PM in 56 year old copper pipe radiant floor heat. Leaks.

Many times these can be found using a thermal imaging camera.The leak will look like a blob among your tubing stripes.
You may be able to rent one in your area.


@ March 18, 2014 1:59 PM in Please critique this design

I am following your logic.
I have real concerns about the low flows you are running through the boiler.
For one, the heat exchanger could be damaged. This is why they recommend primary secondary.
Secondly, If the flow goes too low,the flow will become laminar rather than turbulent.This will trash efficiency.
I would run this one by Lochinvar.
I guess a worse case scenario would mean you have to raise the temps and lose some efficiency. (actually the worst case would be a damaged boiler that is not warrantied)


@ March 18, 2014 9:06 AM in How would you do this?

I understand your thoughts on tankless.
I have always done indirect and they work great. I am pretty sure they cost less and last longer than tankless units.
The lochinar ,or triangle tube with tekmar, will let you do one temp high and then mix the other temp. When only the low temp is calling, the boiler(s) turn down to the lower temp and the mixing valve goes wide open.
I am on the less is more/keep it simple program. When ever possible I will use one appliance rather than 3.


@ March 18, 2014 8:58 AM in Please critique this design

I am not sure how you will get the boiler to condense.
With 145 degree setpoint and minimum boiler flow rates I don't think you will get the low return temps.
I am not a fan of reverse indirect and low temp heat.
The lochinvar is a good choice for mixing although you have to add a mixing module.
Never use a smart tank for reverse indirect. They are steel on the outside.


@ March 18, 2014 12:26 AM in Boiler Was Plumbed Wrong...

The condensate comes from the combustion process.
A dry climate will not help.


@ March 18, 2014 12:24 AM in Boiler Was Plumbed Wrong...

I see what you mean.I don't think you will have a problem with the mixing in that drawing.
I have not tried it that way. I don't see why it would not work.
Anyone else?


@ March 17, 2014 11:36 PM in sizing

What boiler is it?
3/4" for 120k is odd.
Is it a tankless water heater?


@ March 17, 2014 11:31 PM in Boiler Was Plumbed Wrong...

The problem with your present setup and the one you are proposing is that the mixing circulator is not within the heating loop. As soon as the valve is too hot, it will close the hot port and circulation in the loop stops. The only reason it "works" now is that the boiler is turned down so low the valve never reaches that position.

Your boiler must not receive sustained return water temps below 130 degrees or it will be damaged by the condensate. Your aquastat temp needs to be raised.

I think the easiest solution is the one I have sketched. It may be possible to utilize your existing valve. My concern with doing that is that the cold slab may pull the boiler temp into the condensing range.

The I valve will give you outdoor reset which is nice, more importantly it will measure your boilers return temp and automatically keep it in the non-condensing range.

You need to  be sure you have check valve on the cold side of the mixing valve, some have internal ones.

You will need a simple relay to control the new circ, zone valve and I valve. That is another subject.


Triangle Tube

@ March 17, 2014 9:17 PM in How would you do this?

I love the TT boilers.
They don't really do 2 temps at once. They will always default to the higher temp. This does not work with extremely different temps With TT you need a 3rd party controller to do mixing.
I have yet to get my head around why you like installing a demand water heater and a condensing boiler.
The idea of 2 condensing boilers is good if you cascade them in order to increase the turndown ratio and provide redundancy. Running them on separate loads does not do this.
What you are proposing will obviously work. I just see complexities with little benefit.

Less is more

@ March 17, 2014 6:23 PM in How would you do this?

I am looking at a similar job right now.
It has a little less heat loss but also has a hot tub heat exchanger that needs about 20k/btu.

I am thinking of using a Lochinvar WHN110 and the Lochinvar 3 temp mixing add on controller.

One mix temp will be high temp Hot water baseboard.
One mix temp will be low temp infloor heat
The third temp will be the hot tub which I think will run at about 140.
The DHW will be a priority indirect tank

One boiler, done deal.



@ March 16, 2014 8:31 PM in Boiler Was Plumbed Wrong...

If you answer the earlier questions you will get better advise.
I think the only reason the system worked before is that the boiler temp is turned down and the mixing valve is turned up.
Your drawing will not work very well.

Clean Work

@ March 16, 2014 9:33 AM in Boiler Was Plumbed Wrong...

That is a clean install.
You are correct that it leaves much to be desired in the design department.

The boiler pump is pumping directly into the expansion tank. It should be pumping away from the tank. This may or may not give you problems. the good news is that there is very little resistance in that loop, so the pressure differences are slight.

The closely spaced tee's going to the secondary are not so close. They should have 4x pipe diameter (max of 8x)  between them That would be 5" to 10" with 1 1/4" pipe. What you have might work, but again it is not quite right.

You are correct that the mixed loop will never work as drawn. It can't.

You are also correct that the boiler will not last long at those return temps.

I am guessing that your staple up install does not use aluminum plates. Is there a way to confirm this?

If your system is plateless, you could run the boiler and the staple up zones at 150 then mix down the slab zone with a device that will provide outdoor reset and boiler protection. The outdoor reset will help prevent indoor temp overshoots do to overheating your high mass slabs. You could use something like this and another circulator. You would also want to change how it ties into the system. you don't want the other heating circ pushing on it.

Normally, the circ that will not turn off would be wired into the green controller. I am guessing it is presently wired always on.

Do you know what the boiler aquastat is set to now?
What size is the boiler?
How big is the house?
What type of construction/insulation?



@ March 16, 2014 12:59 AM in smart 50 with tankless water heater

I though I recognized the dialect.
The plan looks pretty sound. The alpha needs to "pump away" from the expansion tank. I think I would just move the pump.
Where does the 009 go?
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