Help- old radiant heat thermostats are going bad and new ones don't seem to work

vshafer271

I live in a 200 year old house in Ohio that has an old radiant heat system and has worked well since we moved in about 10 years ago. Previous owner installed it and it was probably 'recycled' from somewhere else based on it's age. The way previous owner explained, there are 'zones' controlled by various thermostats throughout the house. The main level of the house is sort of an open concept; one thermostat controls multiple heating panels (we have two thermostats on main level for kitchen, dining, living, and basement). Upper floors have one thermostat for each panel. One of the thermostats in a bedroom went bad and it was easily replaced with thermostat from Lowes and it worked fine.

Now, two more thermostats went bad and I had an electrician (actually 3 electricians) in to replace but they don't work correctly. The thermostat turns on but never heats up like they did before and seem to cycle on and off a lot. Space does not heat up above 60 degrees where before it would easily heat to 72 degrees even though we never kept it that warm. Initially we were told to return the thermostat to Lowes because it was defective. New thermostats are no better. The old thermostats (they look like 60s or 50s) say 'Lo High Comfort Zone and Off' with no brand name. I'm thinking that there is something different about the thermostats--the old ones can work with multiple units to heat adequately but the new thermostats aren't capable of that for some reason. Again, they heat up somewhat then go off and on. I'm thinking the replacement in a bedroom did work because it is only controlling one unit rather than multiples.

Since it's been below zero here I'm starting to freak out, afraid that the thermostat in kitchen and dining room will crash and leave the main level of our house with no or very little heat other than a small wood stove. Even though I live near a large city (Columbus, OH) no HVAC company we've called will help; they just say they don't work on these systems and that's it. My husband called a company in Cleveland the sells radiant heat systems and they recommended we find a good Electrical contractor and have them come in and make them stay until it is fixed. Easier said than done. Other than this problem, I've been pleasantly surprised at how well the whole system works but always dreaded when something went wrong because there is no one to fix. I'm ready and willing to pay someone to fix this but can't find anyone to touch it. Any suggestions would be greatly appreciated! It's cold here--brrrr!!

nicholas bonham-carter

Where does the actual heat come from-hot water, or electrical heaters?
If an electrical system, then you would think the thermostat wire could be jumpered as a test to see if the fault lay in the thermostat, or in some electrical relay, (more likely).--NBC

vshafer271

Electrical heaters. OK-- I can suggest that to the electrician. Thank you.

JUGHNE

There is a limit on how much heater you can put on 1 thermostat.
Sometimes there is a relay, maybe in the basement, sometimes the heater itself if it has a cabinet, hopefully not in the attic.
1 thermostat could run the relay which in turn could run several heaters.

vshafer271

There is a relay in the basement--so it sounds like there may be a problem with the relay? Would a regular electrician be able to determine if there is and how to fix it? Sorry for all the questions. Thanks.

nicholas bonham-carter

I suspect the relay, or it’s connection to either neutral/hot side or ground.
Any good electrician should be able diagnose and repair this.—NBC

Jamie Hall

vshafer271 said:

There is a relay in the basement--so it sounds like there may be a problem with the relay? Would a regular electrician be able to determine if there is and how to fix it? Sorry for all the questions. Thanks.

Yes. An electrician should be able to figure the system out and get it going without any trouble.

vshafer271

OK I'm back. I had the fourth electrician come out with the information provided here regarding possible problem with the relay box. They tested some things in the box that worked-there is a circuit board of some type that I thought they said could be the problem. ?? They took pictures. The 'head' electrician (very nice) spent some time calling around including a place in Cleveland where we purchased replacement heat panels, and no one would or could help him. No manufacturer name on the relay box, it says J H Crawford Electric Columbus, OH which is no longer in business. Any other suggestions? Does anyone know of someone this current electrician could call or email? He is very nice and hasn't charged us, though money isn't the big issue. He also has photos. I just need it fixed before the next below zero temperatures hit. Thank you.

Jamie Hall

Electric radiant isn't -- or shouldn't be -- rocket science. But your electrician may have to go all the way back to square one to troubleshoot it. There were some ingenious setups... which is to say without documentation they're incomprehensible. Don't ask how i know.

That said. Step one is to verify that the radiant heat wiring itself is intact. Disconnect it completely from any power source and ohm it out. Check and make sure there are no circuit breakers etc. on it which might be open.

Then step two is to put power to it -- no need for a thermostat or relay at this point -- and verify that it heats up. Check the current draw when it is operating while you are at it.

If it passes those two tests, you know that the actual radiant heating wiring is working.

Then it's a matter of controlling when it is working. Lots of ways to do that, but it will probably involve a thermostat and a relay.

I might add that if the radiant doesn't pass those two tests, you are probably looking at a new heat source. High resistance or low current draw is probably one or more broken circuits in the panels; low resistance and high draw would be a short somewhere, cutting out a portion of the radiant elements. Neither is particularly simple to locate, never mind repair if the stuff is buried in the ceiling or floor.

vshafer271

Thanks again Jamie. I will pass this along. Even though this heating 'system' has worked great for the most part until now (we've lived here ten years) I'm thinking we need to find another solution since we don't have anyone like you in Columbus, Ohio.

ratio

You might try Barry Brothers for odd/old parts. No affiliation, just a happy customer.

Can you post pics of things? Someone might recognize the system.

JUGHNE

After doing the 2 tests that Jamie suggests, then any 2 pole relay rated for resistive loads with control coil to match the tstat or control transformer, if one, would work.
HVAC person would have all of it on his truck, I do.

vshafer271

I will share this with the electrician but am not hopeful. Here are some pics including the relay box. It probably won't tell you much since it says high voltage and my husband didn't want me to open it.

vshafer271

More photos of relay box-thermostat and heat panels. Another quick questions- should I be working with an HVAC person or Electrician? I think I'm going to need to go to a fifth person/company.

Jamie Hall

Electrician. A really good HVAC person should know enough electrics -- we have several who do on the Wall, but none near you -- but that is all electrical.

JUGHNE

Both thermostats look to be capable of 240 volt switching.
They are double pole single throw, breaking both legs of a circuit, as shown by the "off" position. (qualify as service disconnect for the unit).

The control box is new to me. Wonder if this isn't some form of rheostat heat control that varies the voltage to the heater elements. Doesn't seem logical as dropping the voltage would heat up the control box.

What do the actual heating panels consist of?
Or is it wires embedded in plaster ceiling?

JUGHNE

Google JH Crawford PE; Started business in 2010, approximately 2 employees, (I count my wife also ).
Site implies located in a residence......no phone number given.

This looks to be a custom built control panel. I wonder if the control knob controls cycle timing of heaters on and off.
Usually not needed for residential heating.......but remember "PE" at the end of the title.
Some things are over engineered sometimes.
This could have been a prototype that never got off the ground.

There might be a wiring diagram inside the box.
If so a picture of that and also the inside of the box would maybe help.

There should be circuit breakers in the panel that would completely shut off any power inside the box.

For about $15 -20 you can get a "non contact voltage indicator" (looks like a big plastic ink pen/marker) from most hardware stores. With circuit breakers off, then remove the cover and check for live power that could be still on in the box. Practice with your new tester on something you know is hot, such as an outlet.

ratio

JUGHNE said:

This looks to be a custom built control panel.

Agree. This is a custom one-off. Who knows how it ended up there, maybe J H Crawford built the place.

You'll need either an electrician who knows a little about HVAC or an HVAC technician who knows a lot about electricity. You might have better luck getting the right skill set at a commercial place (either trade); the only residential thing about this is that it's in a house.

vshafer271

Thanks for all the info...I did find the company and the owners (if still alive) are in their 90s and the phone is disconnected. I'll continue on with this additional information. Wish me luck--the temperature is dropping again.

Zman

I'll bet there is an SRC device of some sort in there.
The contractor you are looking for is someone who has a thorough understanding of controls. It may be an electrician, HVAC or controls specialty contractor.
The next time you have a contractor on site, make sure to get a picture of the inside of the cabinet.

vshafer271

Great--thanks to everyone who replied. I should have taken a picture when they had the box open. I've identified another person-contractor who may be able to help and am sending them the entire thread here plus photos. Thanks again.