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I have a Ferolli Optima 901 when you turn the hot tap on full after a short time the hot water goes off and then the boiler shuts down, if I run the hot tap slowly there is no shut down and hot water is fine but slow.

I was told at service that there was probably a blockage in the Combi Hot water heater/pipe and not repairable so live with it or fit new Combi Boiler we do not have any scale problems in this area.

The Heating works fine on its own, is there a way to clear out the pipes or even replace the hot water heater part.

It doesn't make much sense what the service engineer said, if the water is slowed down going through the boiler the water/boiler will get hotter.

So if it was overheating - it would overheat when the flow rate was reduced, not increased.

All I can think of is that, if the flow of water is restricted it will be forced against the diaphragm fully operating the microswitch, if the flow rate is increased maybe it is passing thorugh the boiler too quick and not forcing the diapragm up enough.

I would try a diverter valve service kit, change diaphragm as it may be stretched or split.

Hope this helps

Hi thanks for the reply but the problem has now changed (Ghosts)?

Now when I run hot tap nothing happens no hot water gas does not ignite pilot ok, but when heating it on ie the burner is lit we get hot tap water ??

Me thinks we will hang on and go for a new boiler(any volunters) this one is 8 yrs old.

:roll:

That again could be diverter valve/diaphragm. The flow of water pushes a pin that connects with a microswitch, if the diaphragm is split the connection wont be made and the boiler wont come on.

Heating eng is more than likely right head towards the diaphram

Hi thanks will get a combi expert in again and tell him what yous have said but wifey now heading towards a new one.

Cheers all

save money and replace diverter valve its not that old

Hi wiill give that a go cheers.

I've had two houses with combis and problem same each time: diverter valve. Present one is 10yr old Vokera, replaced the microswitch because it was on way out and now diverter valve is not diverting fully so heating also comes on. Am looking at replacing valve as well now.

Hi again, Just been through the Optima 901 booklet and unable to see a part called a diverter valve is this the bit No. 136 (flowmeter)?
When I had a quick look at this part looks like someone (previous owner)?
has had mole grips on it lots of scratches as if it was removed not that long ago I only bought the house last year and also it shows a flow limiter is this inside the flow meter ? could it be that this is the problem or have I gone off the rail.