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Floor heat issue

D

DavidM

Active member
One of our floor heat loops isn't melting the ice, this particular loop is for the concrete outside the entrance to our automatic bay. Where the return side of the loop connects to the manifold it is cold when all the other return lines are warm. Is it possible to get an airlock or something in a single loop?

How do I fix it?

David
 
Does each loop in your system have its own pump or does it have one big pump? Most systems i have seen use a pump for each loop and it is usually the pump that goes bad.
 
Hopefully, the system includes shutoff valves for each loop.

Try closing every valve on all but the affected loops.
This forces the pump’s flow through only the affected loops.
If there is an “airlock” this should quickly resolve the problem.

Should the issue return after all valves are reopened, the pump is either undersized or the impeller is failing.
 
Unless you were doing some work on the system recently I'm guessing airlock is not likely, given the temps here in PA I suspect you got a frozen loop, yikes. Fortunately its a lot warmer today.
A couple things:
- +1 on the suggestion to check your glycol
- 5 years ago I decided to flush/clean out the floor heat loops. Holy Smokes there was a lot of crap in there! After upgrading my manifolds (see below) it was really easy to do, I hooked up a hose (city water & pressure) to each loop and ran it in both directions. I then put in a boiler cleaner, and did it again a month later. To this day I am still shocked at how much junk/scale/etc came out. So much that I still wonder how the floor heat ever worked before I cleaned it.
- Whenever single digits are forecast, I bump up the temp on the floor heat for a few days - gas is expensive, frozen anything is worse.

5 years or so ago when I rebuilt my floor heat system, I put in this manifold: https://www.supplyhouse.com/Bluefin-PXPKHM-8-8-Loop-Stainless-Steel-Manifold-Package-1-2-PEX
Replacing the manifold was really not difficult at all.
- ability to adjust flow to each loop individually, lets me really fine tune the floor heat
- flow meters on every loop makes it easy to see if a loop isnt flowing
- inlet & outlet temp gauges

Make it a LOT easier to deal with the floor heat.
 
Hmmm.... You've got me thinking.

My original RayPak system....with original Glycol...runs like a champ after 26 years. I've NEVER done anything to the fluid, except maybe add about 1/2 gal total over all those years.

Should I leave well enough alone....or consider changing/flushing the fluid this spring?

What type of antifreeze? Preferred brand/dilution?
 
I have been told that propylene glycol does not wear out like ethyl glycol that is used in cars. I have had 3 different boiler repair guys tell me this. Do not let either get diluted too much with water.
 
When I rehabbed my Floor Heat about 4-5 years ago, I used "NoBurst" Propylene glycol and mixed it at about 33% with distilled water. That gives the system about a -50° burst temperature, meaning it won't freeze solid until -50° but can turn to slush below zero...I think that mixture turns to slush at about -10°. But if the system is running, its a non issue. For long period's of a power outage, and with the low amperage pumps I use, a small generator will keep it from freezing if the temps are actually that low. It gives you plenty of time to react.

There are several propylene glycols on the market, but this is the one I settled on...I'm sure for a reason I can't recall!
 
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Thanks IB for the link! More reasons to install the highest Energy Efficient system as possible and let it run below 32°. Don't take chances! My complete system only draws 600w @ 120v and sips NG, so the smallest of gen's will keep it going easily in case of extended power outages. It never hurts to be prepared!!
 
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