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.

 

[CountryFan]

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.

 

[jpowell79]

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.

Cheers will give that a go tomorrow

 

[jpowell79]

Ok a pretty sure it’s not the diverter valve as it seems to be moving up and down ok. When I call for hot water it goes all the way up, the burner light comes on and stays on and the water is lovey and hot.

When I turn the nest thermostat on, the diverter valve goes down to the bottom, then the burner light comes on but it only stays on for about 10-15 seconds and then goes back off again.

No blue flashing error lights or anything.

So guess it’s not the diverter valve and not the thermostat….could it be the pump?

Just trying to figure out why the burner light is going off, yet it happily stays on when calling for hot water?

 

[jpowell79]

Ok I fixed the issue and I have to say it’s completely embarrassing!!

Part of me didn’t want to put the solution up here because it makes me look like a right numpty, but sod it, it might help someone else who makes the same mistake with out realising!

Ok so here it is….

My radiators/pipes were making a whooshing noise, so I thought “ah, maybe I should open up all the lock shields and see if it gets rid of the noise, and then I can start working out the route from the boiler and turn them down one by one.

Not concentrating, I’ve locked them all!

So then I turn back on the boiler and suddenly the CH isn’t working, and I’m thinking, “I don’t believe it, just my luck the boilers now packed up completely! Maybe that whooshing noise was the boiler telling me it’s about to keel over!” ….then I’m off on a tangent looking up issues in my phone for faulty diverter valves, pumps, heat exchangers, etc, and before I know it, I’ve completely forgotten what I did with the lock shields!

What a numpty!!