Locating manifold of a radiant floor heating system
Recently acquired a Condo that has propane fired radiant floor heating system. The house inspection showed it to be working. Recently as the cold weather begins in earnest the system cannot keep up… had a local reputable company diagnose the problem which they determined is caused by air in the system. They were able to remove some of the air at the boiler. As they drained water from the system it was very brown. In any case, the heating improved in some of the rooms as measured at the floor with an infrared thermometer. But not all. The thermostat was replaced with a programable model.
The technician advised that he needed to access the “manifold” in order to completely remove air from the various branches . However no access panel for a manifold was found in the condo. The adjacent owners say there’s no access panels in their units.
The furnace room has 5 or 6 furnaces with 2 pipes each running into the ceiling which is completely sheet rocked. Rumor has it that our Condo is the only one left that utilizes the radiant heating the others were converted to hot water baseboard at one time or another.
My question (s) are: How does one go about finding the manifold? Any suggestions as to how to proceed in an intelligent manner? Where to start looking? Can you suggest an infared tool that’ll help locate it? This has become a maddening problem. The thermostat set at 72, indicates its calling for heat but never reaches 72! I’ve confirmed the accuracy of its ambient temperature measurement with an independent thermometer.
Thank you for reading this note. If a reply is beyond the scope of this blog please suggest another resource that would be helpful.
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Replies
This is in fact hard to diagnose over the internet. There are a lot of details that one needs to get right for a hydronic system to work well, and the fact that yours doesn't work well and all of your neighbors gave up on theirs likely means there is more than one thing done wrong. My best suggestion is to tell us your location. With luck, that will result in a tip from someone nearby on an expert who can look at your system in person and give better advice.
It might be that you don't have a manifold, but simply have one big loop, with all the tubing in series. Or it could be that there are T's hidden in the floor where the different loops branch off, even though that should have been done with a manifold.
You might have some success in figuring out how it is plumbed with an infrared camera. Some Home Depot locations have them available to rent. Energy auditors often own them. And it might be that part of the solution to your problem could be improving the envelop so that the heating system doesn't need to be improved. So having a visit from an energy auditor could be helpful anyway.
What I would hope to find with an IR camera would be a location where the floor is hottest, indicating where the start of a loop is. If you find that adjacent corners of different rooms have the highest floor temperatures, the corner where they join could be the location of a manifold or makeshift manifold. If there's a section of wall there that also shows up warm, it might be worth opening that wall to see.
How old is the building? Can you post a picture of the setup at in the basement? One more piece of information that might be useful is the temperatures of the water as it goes from the basement up to your unit, and when it returns from your unit. If you have plastic PEX pipes you could get an idea of that with your IR thermometer. If they are copper, you would need to coat them with something that works with the thermometer first, such as black electrical tape.
Thank you Charlie for the information. Solid suggestions which we will tackle and I'll post the pictures and our location and the temperature information as well, in the next day or so.