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gdc115
Radiant ceiling heat thermostat

I'm not sure if this question belongs here or in heating.

My house has electric radiant ceiling heat. Some rooms are on a double 20 amp circuit breaker and some on a 30 amp double breaker. The 20 amp thermostats appear to be single pole and the 30 amp thermostats appear to be double pole. I would like to replace the existing thermostats with modern programmable thermostats. I can't find any modern thermostats rated at more than 16 amps. Can someone please point me in the right direction?

Thank you.

NEC
Re: Radiant ceiling heat thermostat

The NEC does not allow continuous loads to be more than 80% of the circuit rating applied to your heating. If the 16amp stat you found is rated at 16amps of continuous load then you may be good to go as long as the circuit(s) is/are not drawing over 16 amps. (16amps is 80% of 20amps.)

As far as the 30amp circuits go you could put 30amp rated general purpose relays in line with the circuits with 24volt coils and just convert the control circuit using a 24volt transformer. That way would allow you to use a low voltage stat of your choice.

gdc115
Re: Radiant ceiling heat thermostat

Can I use one transformer to power 4 t-stats and 4 relays?

Thank you,
gdc115

NEC
Re: Radiant ceiling heat thermostat

I am not in my office with access to some quick information for amp draw averages of 24 volt coils on relays but it ain’t much and the stats draw next to nothing.

I would think something like a 75va transformer would be more than adequate. They can be purchased for less than $35.00.

If you go this route I would recommend open contact, double pole, general purpose relays with a resistive rating at 30 amps on the contacts and 24vac coils (Not DC). They will be the most cost effective.

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