Worcester Greenstar 24RI - Heating Staying on

[Rob_Quads]

Over the last 3/4ish months we have hit a problem a coupe of times I can't quite work out.

We have a Worcester Grecnstar 24RI boiler, Drayton Tempus 7 programmer and a Nest. We have noticed that the central heating has not turned off when it should have.

Nest was showing as off.
I turned the heating off on the programmer (essentially removing the Nest from the equation) and the heating still stayed on.

If I power cycled the boiler OR removed/refitted the tempus from the wall bracket then the boiler would turn off and then stay off.

As mentioned it only happened a couple times but I am not sure where to go next to diagnose the problem (which is obviously made tricky by the fact its a intermittent problem.

Any recommendations?

 

[45yearsagasman]

You probably have motorised valves in your airing cupboard. Have a look and report back. It might have no bearing, but it will be a better description of the system.

 

[simond]

Why would you have a Nest and a Tempus 7? Not that it would have any bearing on the fault.

 

[Rob_Quads]

You probably have motorised valves in your airing cupboard. Have a look and report back. It might have no bearing, but it will be a better description of the system.

Yes there is a 3 way valve (and pump). Both of these were replaced 2/3 years ago.

Why would you have a Nest and a Tempus 7? Not that it would have any bearing on the fault.

I still need the Tempus for the hot water (my Nest is the Gen 2 which does not cover the water) Ideally I would have a Honeywell EvoHome install but its just too much

 

[TCCHeating]

Do you have a multimeter Rob?

 

[Rob_Quads]

Yeah I have one. Unfortunately its not so easy to probe behind the tempus but there is a junction box in the airing cupboard where it all goes to (cables are a mess)

 

[TCCHeating]

When the problem next happens you need to get your multimeter out. Make sure hot water is not calling for heat. Check the white and orange wires from the valve. If the white wire is live then it is a problem with the thermostat. If the white wire is not live and the orange wire is live. Then it's the valve

 

[Rob_Quads]

thanks i'll check next time it fails, fingers crossed its not when we are on holiday

 

[gazdaz36]

Do you hear a clicking noise from the boiler when it should be off. This boiler can sometimes continue to fire with a small residual voltage that comes from the 3 port valve. If it makes clicking noises you might just need a capacitor wired in at the boiler to stop this.

 

[Rob_Quads]

Do you hear a clicking noise from the boiler when it should be off. This boiler can sometimes continue to fire with a small residual voltage that comes from the 3 port valve. If it makes clicking noises you might just need a capacitor wired in at the boiler to stop this.

I don't recollect any clicking from the boiler. It sounded fine bar being on when it should have been off

Next time I'll double check for any strange noises