To start with the central heating was fine but the hot water worked when it felt like it. Sometimes i would have to turn the central heating on and my stat up to gain hot water. Now when i try to use heating or hot water it sounds as if it is trying to fire up but failing with a click afterwards repeatedly at about 2 second intervals. How do I fix it?

Lee Burnell, March 2008

The vokera excell 80sp boiler sounds as if it needs its periodic service. The hot water fluctuation is a classic sign of the flue venturi needing cleaning, this causes the differential air pressure switch to drop out. This is an easy job, but new safety legislation means it is now a job for a corgi man. (Try googling vokera flue venturi).

Hot water demand is sensed by a piston being pushed by a diaphragm. The diaphragm eventually holes and needs replacing. When it is replaced clean every scrap of the old diaphragm from the pusher plate and brass insides, or you will have to replace it again in 6 months.
The microswitches in this boiler dont last forever. If the hot water microswitch goes you wont get hot water unless the CH is on (but check/change diaphragm first). If the flow switch goes you will have a boiler that just will not fire up, or a boiler whose pilot light will not stay lit after a period of no demand (because the fan does not slow run). Google it.

Contact www.vokera.co.uk for a recommended local man.

If your corgi man is struggling, there is a free Vokera technical helpline that is helpful.

A proper service may be all that your boiler needs.

c, March 2008

sounds like the solenoid on the gas valve may be faulty or the air pressure switch is dropping out to check the aps test between common and normally closed to see if the power is always there if it comes and goes remove the front combustion cover and see if the boiler fires and stays lit then the aps or fan is faulty to check the solenoid test for constant power at the solenoid if the power is always there the solenoid needs replaced

ricky, March 2008