Help needed with room thermostat install

[highly_defined]

Hi guys, can anyone clarify which cables need to go where on an room thermostat install I'm trying to do?

I've got a Worcester Bosch combi boiler (model 240) which has three connections for a room thermostat:

I'm trying to hook up a Drayton Digistat 3 which has these connections:

Question is, which cable should be connected to which?

I've tried connecting 1-1 as that's common to both ends, and have connected 2-3 and 3-2, but that resulted in 2 blown fuses, so that can't be right either. Can anyone suggest anything before I go any further?

Thanks

[neilball]

Originally Posted by highly_defined

Hi guys, can anyone clarify which cables need to go where on an room thermostat install I'm trying to do?

I've got a Worcester Bosch combi boiler (model 240) which has three connections for a room thermostat:

I'm trying to hook up a Drayton Digistat 3 which has these connections:

Question is, which cable should be connected to which?

I've tried connecting 1-1 as that's common to both ends, and have connected 2-3 and 3-2, but that resulted in 2 blown fuses, so that can't be right either. Can anyone suggest anything before I go any further?

Thanks

Using your drawings as a guide you only require the 1-1 & 2-3 connections to be made, there is no neutral connection on your stat according to your details. The reason you are blowing fuses is that you have connected a neutral connection at the boiler to the live terminal at the stat creating a direct live-neutral short circuit. Most new thermostats of this type make it very clear that you should not connect the earth or neutral connections that may have been required by the old thermostat.

[highly_defined]

Thanks so much, that's worked a treat.

[101music]

ha ha I did the same thing last year! Had to get BG out in the end....Looked very silly in front of the missus. You live and learn I think.