Combi Problems

stevegray

Hello everybody, first post. I have a 6 year old potterton 80 combi that is playing up, if you run a bath or take a shower the boiler will lock out. If you turn on the washer there is a noise like a motorbike starting up from the pipes, and sometimes the heating is coming on with the hot water and you have to turn on the cold tap to stop it. The boiler is insured and has had 3 pumps and a circuit board in 6 years. I had the boiler serviced last week and the guy said it could need a powerflush, i ran off some water from one of the radiators and it is crystal clear.The radiators are also piping hot all over.When the pumps have been replaced (one lasted 3 weeks) there has not been a lot of sludge built up in them. I have not claimed on the insurance as it is still working (after a fashion) and i was told by the service engineer if its sludge i am not covered. any ideas please??
Cheers

Fleeting_Glimpse

How old is the radiators and the rest of the system?

alanobrien

stevegray wrote:

sometimes the heating is coming on with the hot water and you have to turn on the cold tap to stop it.
Cheers

Sounds like a dodgy diverter valve to me, if i were you i would be getting another corgi engineer in to look at it.

MarkyMarkD

It sounds like whoever has been repairing it doesn't have a clue about the fault - 3 pumps, for goodness's sake!

I would definitely support alanobrien's view - and if a sensible engineer diagnoses the actual fault, claim off the useless insurance people.

Skiduck

I'd support Alan's view aswell - sounds like the "paddle" on the valve is knackered. You do not need a powerflush as the whole of the radiator is hot, don't let him con you into one.
However the lock out could be another problem, possivbly a flow switch - also are there any dripping taps?

stevegray

Thanks for the replys, there are no leaking taps and the lockout happens when the hot water has been running constantly for a few minutes. Wolud the diverter valve cause the noisy pipes, heating coming on etc?
Thanks again

Skiduck

stevegray wrote:

Thanks for the replys, there are no leaking taps and the lockout happens when the hot water has been running constantly for a few minutes. Wolud the diverter valve cause the noisy pipes, heating coming on etc?
Thanks again

The diverters acts basically as a rudder, directing the hot water from the boiler to either the CH system or the DHW. If this was faulty there may be a chance that the rudder is not being held in any position (either to shut out the CH flow or the DHW flow) thus just "flapping around" willy and indeed nilly. There will be some tension in the "rudder" when the diverter is changing, but this will still make the rudder kind of "clap" - hence noise in the radiator circuit and strange goingson in the DHW.

I would say that the diverter is failing on the DHW side

Andybez38

Skiduck wrote:

The diverters acts basically as a rudder, directing the hot water from the boiler to either the CH system or the DHW. If this was faulty there may be a chance that the rudder is not being held in any position (either to shut out the CH flow or the DHW flow) thus just "flapping around" willy and indeed nilly. There will be some tension in the "rudder" when the diverter is changing, but this will still make the rudder kind of "clap" - hence noise in the radiator circuit and strange goingson in the DHW.

I would say that the diverter is failing on the DHW side

I think Skiduck is right