It was a really old honeywell one. I originally tried fitting a drayton rts8 combi stat but it didn't do anything so I thought it was my three position port unit. I replaced that but nothing changed. I've narrowed down my problems to the thermostat but now don't have the old one to put back on.
I have bought a new Honeywell dt90e room thermostat because it looked like it would be compatible with the wiring I had for my old thermostat. I have a live, neutral and earth.
When I connect the thermostat everything is fine until it tries to start my heating and then the system trips out. I...