worcester combi 240 BF

[bruceyboy]

Having problems with my combi. The heating is workin fine but the ho

water temperature is fluctuating and other times the water is cold Sometimes when you open the tap not fully the boiler is not firing at all. Is this th flow switch or is it the diverter valve. Any help would be appreciated thank

-- bruceyboy

[John Stumbles]

If the boiler's not firing at all it's likely to be the diverter valve. Can you see the microswitch bit on it? If it's not moving all the way does prodding it make the boiler fire up?

If the boiler's stopping and starting whilst the flow of water is continuous then I'd suspect blocked primary to PHE.

[bruceyboy]

-- bruceyboy

[Ed Sirett]

I may have missed something here This sounds very much like a water flow diaphragm that's split(ting). Does this model have that technology?

[bruceyboy]

years old only says it has a water diverting valve with microswitch assembl attached thank

-- bruceyboy

[Ed Sirett]

And what moves said 'diverting valve' if its a round bit about 75mm diam connected to the incoming cold mains and stuck on the end of the 'diverting valve' then I'd reckon that'll be the water flow diaphragm.

[Mathew Newton]

See if the microswitch is being activated by the diverter plunger when there is a demand for hot water. Try opening several hot taps at the same time - the increased flow may well shift the diverter more if the diaphragm is only partially perished (of course the water will not be heated but it's useful as a test).

See my page at

for some photos of when I fixed ours. If you are doing it yourself you might wish to consider changing the whole diverter instead of just the diaphragm - most people who you'd get in would do probably do this to avoid being called out again (and blamed) when the diverter itself finally pops it. I did just the diaphragm and 3 years on all is still fine so arguably made the right choice.

Mathew