I have Honeywell mercury tilt theromometers controlling the baseboard heating in my home. I want to be able to programme the heat to turn on and off as and when it is needed and I bought some Noma Programmable Digital Thermostats to replace them. The Honeywell thermostats work well but when I connect the Noma one nothing happens - no heat - no didgital display - nothing. It looks idiot proof, two wires coming out of the box in the wall, two wires to connect to the Thermostat - what am I doing wrong??

Is the Honeywell thermostat for 110/220 volts? Is the new thermost for 24 volts? This could be the problem

Is the Honeywell thermostat for 110/220 volts? Is the new thermost for 24 volts? This could be the problem


Thanks for your reply, that is exactly the problem. Any suggestions what digital thermostat would be compatible with my baseboard heaters?

This could be a bit of a mess. If it is a 240 volt heater, you should use a double pole thermostat which requires 4 wires.

Code says you only need to break one side of the 220 volts to control the heater element but both sides have to be protected by a over current device. Fuse/breaker.

Code says you only need to break one side of the 220 volts to control the heater element but both sides have to be protected by a over current device. fuse/breaker.

In non-technical speak for the technically challenged please...

I'm having the same problem, but have central heating.

220 volts uses 2 wires for power. Each wire is 110 volts hanse when combined equal 220 volts. Code requires you only have to have a switch or thermostat that opens up one side of the 220 volts not both to control the heater.Now the disconnect/fuses or breaker has to be a two circuit type so all the voltage will be off when servicing.

220 volts uses 2 wires for power. Each wire is 110 volts hanse when combined equal 220 volts. Code requires you only have to have a switch or thermostat that opens up one side of the 220 volts not both to control the heater.Now the disconnect/fuses or breaker has to be a two circuit type so all the voltage will be off when servicing.
Is it possible to do what I want to do - or should I abandon all hope of digitally time controlling my heating?