combi boiler problem...cured by switching it off and back on again

[smashweld]

more than a couple of times now the thermostat/timer has switched the heating on, the noise coming from the boiler (pump?) is the same as normal but no heat to the radiators

I THINK the same thing happened once with hot water (vague memory)...could hear the boiler firing up but no hot water out the tap, solved by switching it off and back on at the wall

it's a Worcester 24i boiler...are there things I can check or even fix on the plumbing side? or will it need a gas safe engineer to look at it?

cheers

 

[waddycall]

Sounds like the diverter valve isn’t playing ball. Turning the boiler off and on again will reset the valve position. Could be caused by a flow switch or circuit board fault. I’d get someone in to look at it. You won’t be able to get technical advice from Worcester without a gas safe number. Also,if it’s the newer type 24i (greenstar/junior) you need to remove the pressure cover to get to the watery bits. That would be illegal under gas safety installation and use regs unless you’re gas safe registered.

 

[smashweld]

thanks waddy

it's the older type 24i, squared shape with the metal cover at the front that just lifts off, replaced a faulty PRV and leaking fill loop in the past because they were obvious (after asking some questions) faults...I'll get someone to have a look this time

cheers

 

[voipio]

Is the pump actually rotating. I had one last winter, where the pump sounded as if it might be turning, when in fact it wasn't. There was a hum, and enough vibration to make it feel as if it was rotating. It turned out that the motor start capacitor wasn't connected properly and was intermittent. The radiators seemed to have a mind of their own, hot then cold an hour later, even though there was a continuing demand for heating. It had been like that for years!!

 

[smashweld]

now you mention it...might be my imagination but I'd say that the few times the thermostat (Hive) was showing the heating was on but there was no heat from the radiators...there was more noise/vibration than usual from the boiler

again I can't recall 100% but this problem has mainly been when the heating gets switched on first thing in the morning

 

[voipio]

The thing with the intermittent pump problem I mentioned was that, when the pump stopped turning, there was still a demand signal going to the boiler, so it carried on heating the water until the boiler thermostat turned off the heat. Because there was no water flow through the boiler, the residual heat in the heat exchanger was enough to cause the water to boil, and create a bit of a racket, and stressing the heat exchanger in the process.

 

[Dave-sparks]

There's no harm in checking the simple things like bleeding the system, bleeding the pump, check the controls are working etc before calling a pro.
Also check the system pressure, make sure the condensate drain isn't blocked.

It's unlikely any of these things will be the cause of tbe problem, but it's simple things to check and doesn't cost you anything to do so.

 

[Kayos]

thanks waddy

it's the older type 24i, squared shape with the metal cover at the front that just lifts off, replaced a faulty PRV and leaking fill loop in the past because they were obvious (after asking some questions) faults...I'll get someone to have a look this time

cheers

If its the original 24i it uses a Gionani diverter, behind the red expansion vessel.

Much fun to repair