Replace Old Style Dial Thermostat.

[EFLImpudence]

Batteries wrong way round.

 

[bluechilli]

And it really doesnt matter which way round they go? Red in NO and yellow in COM or yellow in NO & red in COM

 

[EFLImpudence]

Not really, but better to put Live to L - Red to COM - assuming red is L.

It would matter if you were using NC as well.

 

[bluechilli]

Brilliant, I'll be doing that in the morning then. What sort of thermostat would use the blue and earth wires then? Just wondered why and old dial one has more wires than a modern programme able one.

 

[EFLImpudence]

Some use the supply for internal workings plus, of course, they don't require batteries.

 

[bluechilli]

Done it with yellow and red and won't power on, display lights but because the batteries are in, is it deffo red and yellow?

 

[bluechilli]

Very fiddly to get the wires in but red is in COM and yellow in NO

 

[AndyPRK]

Maybe your timer fault ? Is it set to on ?

Was it working previously ?

Connect red to yellow directly to eliminate the new stat.

Does it click when the temp is adjusted up and down by large amounts

 

[bluechilli]

It is set to on yep, we always leave it on. It's been working fine, with the old stat, just no timer feature

 

[bluechilli]

Here's both the old and the new diagrams

 

[EFLImpudence]

Yes, definitely red and yellow as you have done.

I may be wrong but I don't think the 'on' (call for heat) symbol is showing.

Do as Andy said and connect the red and yellow - put both in same terminal.

 

[bluechilli]

OK red and yellow together and radiators get hot

 

[EFLImpudence]

So, it's not the system, then but the thermostat not calling for heat.

I think you may have to study the setting instructions.

 

[bluechilli]

Checked instructions still no joy, what are the chances of it being faulty? There is a power button on it and pushing it does nothing.

 

[EFLImpudence]

It's not unknown for new products to be faulty.

Do you get the 'on' symbol

on the display?

You could try putting the yellow in the NC terminal and see if it works the other way round.
That is the boiler comes on when the temperature setting is lower than room temperature.