Forum HomeCA-Modern ForumsHome Maintenance Hotline › Radiant Heat System, etc.

Radiant Heat System, etc.

5 replies [Last post]
Joined: Jul 1 2003

I have been learning about Eichler maintenance from other people's misfortunates and experiences (roof, domestic water, radiant heating, etc.). I have several specific questions:

(1) Some parts of my flooring (tile) are warm while other parts are cool/cold after a night's use of my radiant heat system. Does the system have branches that are closed; I read about "looking in closets" for manifolds, but don't know the purpose of manifolds or see any valves. I have a 1973 Courtyard model with a AO Smith boiler (copper pipes, yeah!). Are there branch on/off valves? If yes, where are they?

(2) In my living room floor near the patio door, there is a 6-inch diameter plate cover, with the name "Carlon" products imprinted on it. I believe Carlon makes electrical juncton boxes (sold at Home Despot), but I wonder whether it has something to do with radiant heat? Any ideas? I think there is a similar one in the MBR, but I have to check again.

Thanks in advance for replies.

Joined: Sep 8 2003

We have had the problem in our house that the radiant heat would not reach all the rooms, which was fixed by replacing the 40yr old boiler with a new one. Another issue might be that the pump you have is not strong enough to cover the entire house - best is probably to consult with a radiant heat expert (Anderson, etc). Our home also has a manifold in the coat closet - which according to the experts is not an original feature but was installed afterwards. It supposedly lets you turn of the flow to specific rooms/areas, but we could never figure out which valve controls which room/area - it's pretty useless, and the system was apparently not designed to control the flow for specific rooms anyway.


Joined: Jul 1 2003

I write this for new Eichler owners who may face a similar issue.
Our's is a 1973 model so your situation may differ.
I finally found the mysterious manifold in the coat closet -- it was hidden by the original wood box which I thought was a step box. The original owner was an engineer so he marked the pipes - - I wasn't imagining the uneven heating - - I felt the pipes and some were cold. Our daughter's room wasn't getting water circulation while the master bedroom was cooking. (Now I worry that some rooms were turned off because of leaks and wasn't disclosed when we bought the house this year.)
I assumed the conventional rule - - clockwise to tighten (close) and counter-clockwise to loosen (open). This seems to be correct, but several of the screw values didn't seem to operate and one had a few drops of water coming out when I played with it (oh oh, but it seemed to have sealed, but I have to check).
I found out from a neighbor that he replaced the screw values with conventional handle valves and has very good control over heat distribution - - too hot, just tighten the valve a bit and if too cool, open it as wide as possible. He also said that AO Smith boiler (again 1973) is powerful enough to heat the additional 500 sf (!!) he is adding.
If your manifold is unmarked, it should be fairly easy to figure it out - - with the system running, turn off one and wait for a room to be cool - - I suggest starting the boiler in the evening when the floors are cold - - as the other rooms heat up, the cold one is easily identified.
My neighbor thought the pipes corresponded to the location of the rooms in a clockwise or counter-clockwise fashion - - it didn't seem so but since they were marked, I didn't ponder too much about it.

I also asked about the Carlon box in the living room -- hidden behind the dust cap is an electrical floor outlet for lamps, etc. -- I was disppointed that no one answered this question but eventually a neighbor told me about it.

Joined: Mar 20 2003

We successfully used the manifold to finetune the heat distribution.
Three things come to mind:
- Each valve usually controls more than just one of the rooms. It could include one of the bedroom plus a bathroom, the corridor etc. Took us a while to figure out the coverage for each valve. If you have carpets in some rooms, you can put additional rugs on to capture the heat for easier indication. Takes a while to figure out, do not rush.
- Our valves do not really work in a clock/counterclockwise fashion as a water faucet. Instead the valve is fully open when the "screwline" on top is vertical, and closed when horizontal. In other words, you need only a quarter turn to go from fully open to closed.
- For the sake of the seals in the valves, you should not constantly readjust the settings. Ideally never once you have found your ideal setting (but if you replace carpets with tile, you will need to readjust again, for instance).

We also had our pump replaced, which improved the heat. Not a very expensive job. The boiler is from what I understand well-dimensioned for the job. If you would like to contact me directly, I can recommend someone for the job.


Joined: Jul 1 2003

Gloria: I wish I had your posting before "playing" with the manifold - - what you said makes sense based on what I've done so far. The "screw" valves seem to act like gas valve - - turn them "in line" to open and a quarter turn (90 d) to close - - this explains why the valves didn't "rise" or "sink" when turned like conventional values. I hope I didn't damage the seals or valves - - I haven't checked to see if all branches are receiving hot water -- my daughter's BR is finally receiving heat but the living spaces seem cool.


Joined: Jul 1 2003

Gloria: are you my neighbor Gloria with a VW and a son who likes basketball?

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.