Worcester Greenstar junior - no CH

[jpowell79]

Combi boilers has packed up again. Hot water is absolutely fine, but no CH.

Am thinking it’s possibly the diverter valve, although I only changed that 4-5 years ago, and am pretty sure that last time it was the other way round with CH working fine but with no hot water.

When I call for hot water, the pilot light comes on and everything is good, but when I ramp the thermostat up, the pilot light doesn’t come on, but also no error messages or anything on the boiler, no blue flashing lights or anything.

what’s the likelihood of it being a diverter valve again? Do they not last very long?

If I disconnected the wire to it, then forced it to CH, would that be a good way to prove it’s the issue?

It’s a Worcester Greenstar Junior, and it’s currently it’s wired up to a nest thermostat with heat link

 

[kidgreen61]

Your boiler doesnt have a pilot light.
I suspect you don't have a combi boiler boiler either.
We need more info.
Do you have a hot water cylinder?

 

[jpowell79]

To be more specific it’s the green burner indicator light. It’s 100% a combi

 

[RandomGrinch]

If I disconnected the wire to it, then forced it to CH, would that be a good way to prove it’s the issue?

You can attempt to bridge out the Nest Heatlink, to rule that out as the problem.
With the power safely isolated, place the wire in terminal 3 of the (Gen3) Heatlink, into terminal 2, along with the wire that is already there.
If the heating comes on when the power is restored, blame the Heatlink.

If the Heatlink isn't gen3, or you don't understand the wiring, post a picture here.

 

[Stuckinarut]

what’s the likelihood of it being a diverter valve again? Do they not last very long?

Could be the diverter, especially if system water not good. Could also be the stepper motor. Could also be as per @RandomGrinch being the heatlink.