Hi there

I have just bought a Horstman DRT2 room thermostat to replace my old manual one. The trouble is when I took the old one off, there are three wires Red, yellow and black which go into three separate (numbered) terminal connectors. The new thermostat has three terminals NO, COM and NC and I haven't got a clue which wire goes where. Can anyone help please... before I electrocute myself.

Thanks

It sounds like you have a line voltage thermostat, did you notice what the terminals were lettered in relationship to the wire colors?