Hot water has stopped working on Vokera excell 80 SP?

Pilot outage can be caused by the fan not slow running when there is no hot water/ch demand. This is needed to scavenge combustion products from the pilot to stop it suffocating. Possible reasons are the flow switch being stuck in the flow OK position (not good if it fires up with no flow due to dicky switch operation) , sticky fan bearings, dry joint on slow run resistor etc. The diaphram and pin assembly that actuate the boiler flow switch are replaced when the service kit t0019 is fitted (as part of the normal periodic upkeep).One for the Vokera specialist realy. The DHW demand microswitch can become faulty as well as the diaphragm holeing.
I would guess around 100 quid for a service, but ask for a quote for a service of your model, and make sure it is someone familiar with it, not just a corgi generalist. kit t0019 should figure in the bits he will fit as standard.

c
September 2007

Thanks boys, my father, a retired plumber, was told it would be the diaphragm, which he duly replaced and found the old one intact. He replaced it, the system then worked then the pilot went out. He re-ignited it and it is still running.
I am having an engineer who is familiar with this boiler, out to service it. However, actually getting him out is the problem! I am obviosly concerned until I have a registered bloke check it out. I know it is an old system now, 12-15yrs but according to the engineer, "anything is fixable"

And yes, the pressure is fine. How much would a genuine bloke charge for a service??

Many Thanks for your replies chaps.

lesley-anne
September 2007

Probably just needs a Vokera service job for another year or mores reliable operation, make sure its a Vokera specialist who does it though. Contact vokera for a local man (www.vokera.co.uk). He will replace a few bits that wear, check the expansioin vessel and burner pressures, and clean all the bits that need cleaning.

If you want to DIY google 'vokera venturi'. The flue venturi may need cleaning, or the flue flow is inadequate (nest in flue, sticky fan bearings/dirty fan, dirty heat exchanger etc). Normally a dirty venturi produces hot water cycling, rather than hot water and then permanent cold. You need to get a copy of the manual first (can be downloaded as pdf from vokera website). You need to be careful in reasssembling the boiler, flue gas leaks into living space are potentially lethal.

The system pressure is OK, isnt it?.

c
September 2007

your problem could be that the plate heat exchanger is blocked and requires cleaning and descaling which in itself is not a big job

alan
September 2007

simple, take the large centre screw off the pump insert small flat screwdriver and turn.u may loose a bit of water. pump is stuck also try hitting with hammer. do all this while on

kris
September 2007