Timer Firing Up Boiler for Water, not for Heating

[Mark Walsham]

OK thank everyone so far, I do believe the culprit is the motorised valve under the boiler. I listened to this very carefully this evening, and when calling for CH, I can hear the motor running, but it is very slow. Much slower than when the call for the CH stops.

Additionally, after giving the manual lever a few cycles back and forth into and out of the locked on position, it now seems to work OK when the system calls for CH!!!

So, clearly this is the root of the problem and I am sure sooner or later it is going to give out completely!

Can I replace just the motor housing, motor and associated gubbins or do I need to replace the motor and valve unit?

As a very amateur DIY’er, I am filled with dread on draining the system to replace the valve, so any advice is much appreciated.

Thanks all,

Mark.

 

[ShaunCorbs]

Best to replace the whole valve and get a gas safe engy in if your unsure

 

[Last Plumber]

More often than not you can replace the motor.

It is 240V so be careful. Fuse pull, don't just switch off.
Always test it is dead, never presume.

I would take the motor out and see how the valve feels first. If it opens and closes nice and smooth and there are no teeth missing you could easily change the motor.

If in doubt, do what Shaun says and swap the valve.

 

[Harvest Fields]

OK thank everyone so far, I do believe the culprit is the motorised valve under the boiler. I listened to this very carefully this evening, and when calling for CH, I can hear the motor running, but it is very slow. Much slower than when the call for the CH stops.

Additionally, after giving the manual lever a few cycles back and forth into and out of the locked on position, it now seems to work OK when the system calls for CH!!!

So, clearly this is the root of the problem and I am sure sooner or later it is going to give out completely!

Can I replace just the motor housing, motor and associated gubbins or do I need to replace the motor and valve unit?

As a very amateur DIY’er, I am filled with dread on draining the system to replace the valve, so any advice is much appreciated.

Thanks all,

Mark.

Can you post a pic of the valve to see if the head will come off? You cannot remove it on some. How old is the valve? I personally wouldn’t change the whole thing if it is only a couple of years old.

 

[Mark Walsham]

Here is a pic of the motorised valve, a Honeywell unit, and for some reason there is no label or serial/model number on the unit! We bought this place about 10 years ago, and I think the boiler is approx 12 years old.

I am reasonably happy to replace the head unit myself as the wiring seems fairly straightforward, but my question is this...

Once the head is off, what is an easy way to check if there is wear to the valve itself?

As if there is wear, I shall get a plumber to come out and replace the head and valve in one go, but I hear that these valves are pretty reliable.

Anyway, as usual, any advice much appreciated!

Cheers, Mark.

 

[Harvest Fields]

Looking at the location of the valve I would say it looks awkward. I would get someone in to change it for you.