2 wire thermostat

[manxman]

I'M just about to install a new thermostat unfornatley i have forgotten which wire goes were does the red wire go in to No1 and the Black wire into No 3 or No 2 thanks

[Andrew Gabriel]

There will be a picture inside or with the new thermostat. If you just have a 2-wire connection, then the neutral terminal on the thermostat isn't used (if it has one). Strictly, the black wire should have a piece of red sleeving pushed onto it as it's a switched live (although you'll almost never see this done).

[BigWallop]

It depends whether your heating system takes Normally Open or Normally Closed control. Check that first.

[Doctor D]

If it's new it should have instructions. The red/black shouldn't matter as it's just a switch, but you will need to be sure of using the correct two terminals. I've just fitted a Horstmann DRT2 which stipulated that it depended on the type of heating load you were breaking whether you were using NC or NO for load. Red (feed) always had to go to COM on mine.

[pauld]

Doctor D - I am trying to replace a Drayton RTS1 with a Horstmann DRT2 The Drayton has 4 cables going to it, a neutral, a live, an earth & call for heat - which I presume is the thermostat switch. The Horstman only shows 2 connections to be used, the NO & the COM with the neutra going straight to the heater - help please. Where do I put the neutra & does the live just go to the COM with the 'call for heat' cable goin to the NO?

-- pauld