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larryf
Dec 21, 2006, 05:30 PM
I have an older wall heater with no apparent AC connection. What is the rating of this heater in terms of voltage? I see a gas connection of course, but no AC. I am having a heck of a time connecting up a thermostat. The programmable thermostat didn't work. So I got a round CT87N round Honeywell thermostat. It says it's for 24 Vac heating. Can I use this thermostat?.

There are only two wires coming off the wall heater. Where do I connect the two wires to the thermostat? Currently R &Rc are jumpered together.

Thanks very much!!

labman
Dec 21, 2006, 05:59 PM
Follow the wires and the gas pipe into the heater. They should meet at sort of a box. The box is a gas valve, and should have a label on it giving the voltage or millivoltage. Post what you find.

larryf
Dec 21, 2006, 06:12 PM
This is normail - no AC to the wall heater?

All I could read was General Electric b60 Gas valve and a serial number...

Thanks for your help!

labman
Dec 21, 2006, 08:28 PM
Connecting the 2 wires to the R and W terminals of the thermostat may work if it is just a simple mechanical switch. If not, one of the people with wider experience here should be able to help.

letmetellu
Dec 21, 2006, 09:23 PM
Some older wall heaters use what is called a "pilot generator" to create it own voltage, about 750 millivolts which it 3/4 of one volt. This furnace uses a special thermostat that will work with millivolts. Check the new thermostat and see if it says it will work with millivolts. If not you will have to change it, and I an not sure you will find a programmable one.

Do you have a thermocouple on your furnace?? If you do then it is not a millivolt system, a millivolt system will have two wires coming off the pilot and going to the gas valve, then there will be two wires going to the thermostat. If you pilot is lit and the generator is working, you can touch the two wires together at the thermostat and the furnace should come on it about 30 seconds.
Post more information if you find more.

larryf
Dec 22, 2006, 12:03 PM
Hi... the heater goes on even when there's no thermostat attached!. I have to shut off the gas to the gas valve to shut the heater off!. It is a millivolt ssystem..

What is the solution?

Thanks very much!

Larry