Terrier room thermostat wiring help

Hi

Could someone help me out with the wiring on a Terrier TRT room thermostat please? I bought it to replace an ancient thermostat which I think is now faulty.

My particular model is a TRT 1W. It has four terminals, labelled 1 to 4. It also has an earth tag, which I don't think is necessary for this model, but I could connect it anyway.

The wall wiring has four wires - red (permanent feed?), yellow (switched?), Blue (neutral?) and earth - this isn't connected to anything on the old thermostat.

Could someone please take a look at the wiring diagram (there's a link to the scanned image below) and let me know which wire should go to which terminal?

http://s556.photobucket.com/albums/ss9/shovers/?action=view&current=TerrierThermostatWiring.jpg

Many thanks

James

Try:

Red (Perm live) 1
Yellow (Sw Live) 3
Blue (N) 2
Earth to the earth terminal
Terminal 4 isn't used.

Only you can determine if red is live (from the programmer - it should become live when the heating is switched on)

blue neutral and yello switched live.

You can test this with a multimeter. If it test out OK them connect the yello & red together (power off first!) switch on and the boiler & pump should run.

If all that checks out OK then

Red to 1
Blue to 2
and I would expect the yellow goes to 3



Try it like that, if your heating comes on when it should be off then just move the yellow to 4.

Sorry - cant be more exact than that, but you have the instructions and I dont.

Also not sure what cooling load is but looks like:

1 Red (becomes live when heating is on)
2 Blue Neutral
3 Yellow switch line

Something like air conditioning control?

could be right there mate

Hi

Many thanks for your help - thermostat is now fitted, at least it looks a lot better than the old one!

Unfortunately, it doesn't actually seem to have solved the problem. Basically, when central heating control box is switched to 'hot water - on', the boiler fires up. However, switch it to 'central heating - on', and the boiler will not fire up, and will just remain on the pilot light - that's why I thought the old thermostat was faulty. However, adjusting the new thermostat results in the same problem - ie. it has no affect on the boiler.

I've set the 3-way actuator in the airing cupboard to 'manual', so we at least have central heating - now, the hot water goes to the water tank and the central heating system, so you can't have one or the other, only both on or both off.

The boiler is an old Baxi Bermuda back boiler, but as it can still fire up and provide hot water and heating, it seems to be OK. I guess there is some sort of fault in the control system - before I give in and reach for the Yellow Pages - anyone got any ideas?

Thanks again

James

PS. I'll post this in the central heating section as well.

Thanks

James

If the heating won't switch on, this suggests the 3 way actuator is faulty. The heating circuit is completed by a switch in the actuator, which should close once the motor has moved to the heating position.
If the motor fails or the valve sticks, the switch will never operate and the heating won't start.