Central heating stops working when I'm away...

[Thorne10]

Well, what a week for plumbing and central heating!

I've noticed over the past couple of months that my central heating stops working whenever I'm away from home for more than a day. I keep coming back to a cold house!

If I select ADVANCE when I get back, the boiler (Baxi Genesis combi) kicks in, but doesn't pump water around to the radiators. I guess that's what it's doing on the timer whilst I'm away.

But, if I turn on a hot tap for a couple of minutes, the boiler seems to "reset" itself and start pumping again.

Has anybody come across this peculiar problem before? It's driving me crazy...

Thanks!

 

[Agile]

It may be a sticking diverter valve but more likely a flow switch issue.

The system flow switch can be removed and cleaned and this may well solve the problem.

But there is also a filter in the CH return valve area and this should also be cleaned.

These are not considered as very easy boilers to work on and they are not well understood by many engineers.

Tony

 

[Thorne10]

Cheers Agile. Yeah, I'm starting to appreciate that the Baxi Genesis isn't the professionals' favourite!

Thnaks for the tip re. flow valves and filter.

I'm wondering if, with no-one here to engage the hot water, the system "locks up" somehow after ~24 hours or so (just guessing). The CH should still come on via the timer though, like it does - without fail - when I'm here.

The boiler needs a service - and safety cert - anyway.

Pity that the only sure way to test for a fix is to go away for a few days (or not use the HW!)...

 

[Agile]

That would imply its more likely to be the diverter valve.

But boilers also have an apparent ability to work fine when they are being watched.

In spite of what owners tell me about the boiler faulting all the time nearly 50% work fine when I go to see them.

Or could the owners be exagerating? Once the wife told me it faulted about 12 times a day. Seperately the husband said about once a day! Whom am I to believe?

Tony

 

[Thorne10]

Oh dear. Went to check the flow valve for the CH. It looks a bit blackened. But upon re-assembly, the CH won't fire up at all now. Didn't expect quite so much water to spurt out. Hope it hasn't caused a short...

 

[Agile]

Didn't you isolate the boiler and drain off the pressure and some of the water content?

In saying what is likely to be the fault we have to assume that anyone trying to fix it will have a certain basic appreciation of the need to drain parts etc.

The flow switch IS black and usually have a coating of black gunge over them when removed to inspect.

Tony