Can't Get Air out of Hydronic Radiant Floor Heat Zone

wanttolearn

One of the bathrooms in my house has a separate radiant floor heat zone, which is not working currently. My HVAC company has been out and they say there is air trapped in the system, and they cant find a purge valve to get it out. They want to charge me an arm and a leg to put a purge valve in, and even then wont guaranty that it will fix the problem.

I am attaching some pictures below, so you can see how the system is set up:

The water is fed from my main steam boiler, through a TACO circulator, into a PEX tube (red) that goes through the ceiling into the upstairs bathroom. There is a return PEX tube (also red) that comes back down, which at the bottom splits into two, with one part returning to the back of the boiler, and the other part (blue PEX) returning to the front of the boiler, below the TACO circulator.

My first question is: does this system even need a purge valve? wouldn't any air in the system just empty into the steam boiler? since the water comes from the boiler, and one part of the return also ends up in the boiler, it seems to me that the loop should be able to get rid of any air bu itself without a purge valve?

If that is not the case, and it needs a purge valve, there is a valve on the return tube that I suspect might have been put in for this purpose. I am attaching a close-up picture below. if I close off this valve on the return tube, and then unscrew the tube right above the valve, would this allow the water to flow out and purge any air? do you foresee any risks or dangers in doing so? can the water on a return loop be hot enough to burn the skin? if i unscrew it, and then reconnect it again, will i trap air again?

before i pay the HVAC thousand of dollars to fix this, I would like to get some feeback from any of you out there. Thanks!

Zman

Unfortunately your install is a major hack job.
A purge valve is not going to make it better.
We don't discuss pricing here. What is the fix they are proposing.
Carl

wanttolearn

they said it needs a purge valve installed. nothing more detailed than that. can you be more specific as to why it is a "hack job"? what is the problem you are seeing?

KC_Jones

I can not address your piping problems, but I would make a few comments re: hack job. Speaking as a homeowner the piping should be "pretty". It sounds weird pipes shouldn't be pretty right? Well it should look pretty in the sense that it seems like someone took the time to think about how it should be laid out which pipe needs to go where and done in an orderly, neat and clean fashion. I see homeowners posting pics on here a lot and don't see these things. You don't necessarily need to know what you are looking at, but you should easily be able to recognize a quality install from a "hack job". I have seen piping done professionally that I would hang on the wall in my living room it was so pretty. If you look at your install does that thought even cross your mind? To me this speaks to what was done where you can't see. If your contractor cares so little for their craft and for your house to do a nice clean install, how much effort do you think they are putting into the function of your system? To me in your pics without even considering function at all you have a hack job. And obviously by the fact that you say it isn't working correctly it's a functional hack job as well. I know this doesn't answer your question, I just felt the need to throw it out there for your information as well as any other homeowners that may see and read this. Honestly if the company you have looking at this now isn't pointing this out to you shame on them. They are telling you something and not promising a fix? ANYBODY can do that. I could stop over and throw a bunch of parts at it and say...this might work. In the meantime you are paying me money to not fix it. You need a contractor that will come in and give you the "bad news" it wasn't done right in the first place and then they work up a comprehensive plan/estimate to correct it so it works. Just my $.02 as a fellow homeowner.

Zman

The workmanship is the first give away but not necessarily the problem.
It is very difficult to keep an open system purged when it is above the waterline of the boiler. The water will keep finding it's way back and causing the same problem. Not to mention the fluctuations in the boiler's water level.
The circulator should not be made of ferrous metal when installed in a oxygenated environment.
The circulator is installed at or above the boilers water line. It is probably running dry.
Radiant heat should not be running at 212 degrees.
Pex tubing should not be seeing 212 degree water.
All near boiler piping should properly secured and not running against hot flue pipes.

To get your system running well will take some work. The design will include a separate closed loop with a heat exchanger and associated parts.

Carl

icesailor

How about Non O2 barrier water PEX tubing with irrigation clamps to hold it together?

How about needing a heat shield where the tubing is rubbing on the boiler exhaust vent and there is burned plastic there on the metal. I hope the LWC is working because if it isn't, and the water runs or is pushed out, there goes the boiler.

How do you know his price is too high? Do you know how long it will take care of this aggravation? Even after adding a "purge valve", it still might not work. Did you pay someone to do this, was lt already there? Or did you do it yourself?.

delta T

I am having a hard time seeing how this ever really "worked" at all. If you ran 212 water through the floor, it would be ruining almost any floor that was subjected to it, (not to mention burning the hell out of anyone trying to walk on it). If it is very poorly attached staple up then it may not do either, but in that case it would most likely not really heat at all.

The ferrous pump will not last long (if it isn't already dead) and the idea of installing the pump so high relative to the water line is a perfect indicator of a complete lack of knowledge about both hydronic and steam heating in general on the part of whoever did this. The workmanship has been attacked sufficiently by everyone else so far, but I can't resist. It is, to sum it up in a word, atrocious. The only real fix is as others have said here: install a separate closed loop with its own expansion tank, air separator, and its own pump and associated controls to the radiant side, then use a heat exchanger to take heat from the boiler. While not outrageously expensive (though I suppose that is always subjective), this would be a major proposition. Even with this fix there is no guaranty that it will even work anyways. The only problem that this would address would be to make sure there is actually water in the radiant zone all the time and give a means of controlling the temperature in the tubing. I do not know the condition of the radiant tubing, its spacing, the manner of its installation, the heat loss of the room or any of the myriad of considerations that any competent heating professional would consider upon looking at something like this. Given the manner in which this was connected to the boiler however, my hopes would not be high.

Now all that being said, is there a reason why this room has radiant? Was there steam there at some point? Why not put a radiator back into the bathroom and connect it to the steam system. That may very well be the same cost as "fixing" your radiant floor. Or if radiant is wanted in the bathroom, then do an electric mat, and abandon the existing radiant.

"Purging" is the very least of your worries. You have gotten some very good advice from the professionals here, I suggest strongly that you do your research, and find a good heating contractor to help you solve this problem. I am a little leery of a contractor who either did not see the issues inherent in this setup, or did not tell you about them and suggested a "fix" that will not work for more than a few days (if it works at all).

Please understand that if anyone (including myself) sounds like we are angry or accusatory it is because we see situations like this much more often than we would like to, and in these situations we are often accused of being dishonest and of "price-gouging" when we suggest the real solution to the problem that was caused by someone else's excessive frugality or ignorance in the face of misrepresentation on the part of a dishonest or ignorant contractor. This can engender a certain amount of hostility on everyone's part, but please do believe me when I say that what you have gotten nothing but excellent advice, and that if we sound angry it is directed at the ***hole who claimed to be able to install radiant heating for half the cost of the competition. This is what you end up with and now, unfortunately for you, it is yours to deal with.

wanttolearn

Thanks for all your feedback. I will review all your comments with my HVAC company. Greatly appreciated!

RobG

delta T said:

I am having a hard time seeing how this ever really "worked" at all. If you ran 212 water through the floor, it would be ruining almost any floor that was subjected to it, (not to mention burning the hell out of anyone trying to walk on it). If it is very poorly attached staple up then it may not do either, but in that case it would most likely not really heat at all.

The ferrous pump will not last long (if it isn't already dead) and the idea of installing the pump so high relative to the water line is a perfect indicator of a complete lack of knowledge about both hydronic and steam heating in general on the part of whoever did this. The workmanship has been attacked sufficiently by everyone else so far, but I can't resist. It is, to sum it up in a word, atrocious. The only real fix is as others have said here: install a separate closed loop with its own expansion tank, air separator, and its own pump and associated controls to the radiant side, then use a heat exchanger to take heat from the boiler. While not outrageously expensive (though I suppose that is always subjective), this would be a major proposition. Even with this fix there is no guaranty that it will even work anyways. The only problem that this would address would be to make sure there is actually water in the radiant zone all the time and give a means of controlling the temperature in the tubing. I do not know the condition of the radiant tubing, its spacing, the manner of its installation, the heat loss of the room or any of the myriad of considerations that any competent heating professional would consider upon looking at something like this. Given the manner in which this was connected to the boiler however, my hopes would not be high.

Now all that being said, is there a reason why this room has radiant? Was there steam there at some point? Why not put a radiator back into the bathroom and connect it to the steam system. That may very well be the same cost as "fixing" your radiant floor. Or if radiant is wanted in the bathroom, then do an electric mat, and abandon the existing radiant.

"Purging" is the very least of your worries. You have gotten some very good advice from the professionals here, I suggest strongly that you do your research, and find a good heating contractor to help you solve this problem. I am a little leery of a contractor who either did not see the issues inherent in this setup, or did not tell you about them and suggested a "fix" that will not work for more than a few days (if it works at all).

Please understand that if anyone (including myself) sounds like we are angry or accusatory it is because we see situations like this much more often than we would like to, and in these situations we are often accused of being dishonest and of "price-gouging" when we suggest the real solution to the problem that was caused by someone else's excessive frugality or ignorance in the face of misrepresentation on the part of a dishonest or ignorant contractor. This can engender a certain amount of hostility on everyone's part, but please do believe me when I say that what you have gotten nothing but excellent advice, and that if we sound angry it is directed at the ***hole who claimed to be able to install radiant heating for half the cost of the competition. This is what you end up with and now, unfortunately for you, it is yours to deal with.

Well said!

SWEI

How big (in square feet) is the radiant zone? How was the tubing installed (embedded in concrete or Gyp-Crete, stapled up from below, and with or without heat transfer plates)?

If it's just the one bathroom, a small electric boiler would cost you quite a bit less (built-in controls and no heat exchanger or oxygen barrier issues as long as you pick the right unit.) Even less expensive would be to replace the tubing with electric resistance mat or tape -- assuming that is even possible at this point.

billtwocase

I hope that your HVAC guy was not the original installer of that mess. I wouldn't add a purger to a non operational zone. I Agree with all of the above