Boiler/ HW fine, but heating not starting up? Clock, t/stat or something else?

[Fez111]

Hi all, are you able to advise if I've missed something please?
I have a main combi eco boiler. All appears to be working fine with hot water etc, no error codes, pressure fine.
I recently turned the setting over hw&heating to test before winter kicks in (was on hw-only over summer). However the heating option is not triggering the ignition to come on (ignition comes on fine when needed for hw). Have set heating on boiler to constant/on, and the thermostat is also on full.

I figured since the boiler is otherwise working fine, something is not telling the boiler to switch the heating on.

Checks I ran:
- I set the clock (analogue) to correct time, and it's keeping time as normal.
- When turning the thermostat dial, i get an audible click as what i guess is the current temperature (eg, it clicked at 19°, and couple days ago when it was colder it clicked 15°)
- Have reset the boiler both via dial, and also at the wall spur.

Could this be either of them parts? or is there something else that I may have completely missed, or misdiagnosed?
Thanks in advance guys
Ps - Have attached pics in case you can see something I've missed.

 

[CBW]

Could be the selector switch on the front or the clock switch, try selecting the timer function and see if that brings the heating on.

 

[Fez111]

Could be the selector switch on the front or the clock switch, try selecting the timer function and see if that brings the heating on.

Thanks. I just tried setting to timer and adjusting clock but that doesn’t seem to have triggered it either.

 

[Fez111]

Is there any value in swapping out the thermostat to eliminate this since these are fairly cheap to buy? Before doing this though, the thermostat does click at the current room temperature when turning - does this mean it's working fine and no need to change?

 

[CBW]

You could link the wires together or test with a multimeter?

 

[ianmcd]

when you put the control knob on the boiler to 0 does the display go blank ?

 

[DP]

Move the left hand control between summer and winter mode a few times to clear the contacts if connection is poor

Then, on the timer, the little selector that selects O, timer and I, move that a few times to clear possible dirty contacts.

The summer winter selector brings into circuit the timer for winter running and switches it out for summer running. Electrical testing would be the next step; suppose replacing the thermostat is an option but be aware it is at mains voltage and most likely has three wires plus earth. Unless you know which is which you could get yourself tied in knots trying to figure what to do. There are ways to prove boiler operation for winter tun, but that involves going into the boiler.

Moving the forward, leave the boiler in winter mode, let the clock do the selection

 

[Fez111]

You could link the wires together or test with a multimeter?

Thanks Chris, I have attempted to link the wires to bypass the stat (as in the pic attached) - but this has not triggered the heating. Is this definitive that it's not the stat, or would you consider changing anyway?

 

[Fez111]

when you put the control knob on the boiler to 0 does the display go blank ?

Yep, when put to zero, the display does go blank. Comes back on as normal when selecting summer or winter mode.

 

[Fez111]

Move the left hand control between summer and winter mode a few times to clear the contacts if connection is poor

Then, on the timer, the little selector that selects O, timer and I, move that a few times to clear possible dirty contacts.

The summer winter selector brings into circuit the timer for winter running and switches it out for summer running. Electrical testing would be the next step; suppose replacing the thermostat is an option but be aware it is at mains voltage and most likely has three wires plus earth. Unless you know which is which you could get yourself tied in knots trying to figure what to do. There are ways to prove boiler operation for winter tun, but that involves going into the boiler.

Moving the forward, leave the boiler in winter mode, let the clock do the selection

Have turned the control knob between summer and winter mode few times. Have also done similar with the timer/clock to switch between constant, timer and off. These have not triggered it unfortunately.

I did try to bypass the stat by linking the wires (I've attached a pic to check I done it correctly).
I'm not averse to going into the boiler (have changed phe, diverter valve, etc in the past) if I know what I'm looking for or can google instructions for a procedure.

Lesson definitely learnt re leaving it on winter mode!

 

[DP]

Do you see 240 volts on the thermostat wires

 

[CBW]

Thanks Chris, I have attempted to link the wires to bypass the stat (as in the pic attached) - but this has not triggered the heating. Is this definitive that it's not the stat, or would you consider changing anyway?

Definitive would be testing, but that should bring the heating on if the voltage is correct as per @DP

 

[DP]

That brown and blue pair, try shorting that further towards the boiler

Hint. Boiler comes with a link that is removed for thermostat. Can not say anymore
Unless the above pair has a break in it, I suspect a pcb issue

 

[ianmcd]

could be the timer itself, it will have a L&N and two switching wires, join the two switching wires together same as you have done with the stat, now you have ruled out all heating controls so if it doesnt come on its a boiler fault

 

[ianmcd]

Yep, when put to zero, the display does go blank. Comes back on as normal when selecting summer or winter mode.

That is you testing that the control knob spindle hasnt snapped, but that is fine it is doing what it should