Badi duo Tec combi 28

[markyyyyyy]

I've just installed a Honeywell dt90e thermostat and to check it out I turned the dial on my boiler to the hot water and radiator symbol.

I assumed that I could keep it on that setting on the boiler, and control the heating using the thermostat. IE. Coming on and off to regulate temp.

When the room temp was 20 degrees I turned down the thermostat to 17 degrees and the green radiator/central heating light was still lit and the boiler was still working. Is this supposed to happen? I thought the thermostat switches boiler on and off as per temp if required?

 

[gas112]

so was there a room stat already there and you have changed it for a dt90 ?
how many wires did you use and what terminals did you put wires into

 

[markyyyyyy]

Yes, it had yellow, red, blue and earth.

I have made blue and earth redundant

Red cable has gone into slot A on new thermostat
Yellow cable has gone in to slot b?

 

[ianmcd]

Does your boiler have an internal timer on the control panel ? if it does this will have to be set to constantly on , same if you have an external timer anywhere

 

[markyyyyyy]

Does your boiler have an internal timer on the control panel ? if it does this will have to be set to constantly on , same if you have an external timer anywhere

Doesn't appear to, here is a pic of th front panel

All I have elsewhere is the thermostat itself.

 

[ianmcd]

Your boiler is switched to HW only

 

[markyyyyyy]

Your boiler is switched to HW only

At the moment it is but I've turned it to just hot water because my boiler was running even when my thermostat was set below the actual room temp

 

[denso13]

The wiring seems correct. You could disconnect the yellow at the thermostat and check the heating goes off. If it does it sounds like a problem with the stat.

 

[MeldrewsMate]

The wiring seems correct. You could disconnect the yellow at the thermostat and check the heating goes off. If it does it sounds like a problem with the stat.

Doogle, where did you see the wiring? I only saw the description from the OP. Are you commenting on a convention for colour coding? Could it be that the OP's wiring is not conventional?

OP, do you get the same results if you turn the new stat to a very high temperature?

 

[denso13]

Doogle, where did you see the wiring?

I looked at the OP's post history and one shows the old stat wired up. This suggests the wiring colours were used "properly". I know the aren't always correct.

https://www.diynot.com/diy/threads/which-cables-which.545589/#post-4639040