vokera boiler excell 80 SP is 5years old. radiators in the house are hot, however, there's no hot water anywhere in the house. each time water is released into the pipe, level of pressure goes down to below 1. why is this happening, and do i need to adjust something to restore hot water???

segun awoloto, October 2007

Heat exchanger needs replacing. Engineer changed mine,labour £45 Part £102.....buy part on line for £55 or less..nice profit eh?

Gordon Wilson, March 2008

I had a similar problem on my Vokera Linea 28 & it was a DHWT (domestic hot water thermistor) that has packed up. which screws into the DHW heat exchanger. I had the engineer come & change it & it took him 5 minutes & the part only was about £10.

(A thermistor is a type of resistor used to measure temperature changes)

Steve Bedford, October 2007

Steve, you probably need to replace the domestic hot water diaphragm. This pushes a plunger/pin that operates a fulcrum arm that moves the three port valve & operates a microswitch to turn on the boiler. Download the manual from the www.vokera.co.uk website. When you replace the diaphram make sure that all traces of the old perished one are removed from the plastic plate and brass insides, or you will have to replace it again after six months or so. Its a common fault and easy to fix.

c, October 2007

This isn't an answer, but I have the very same problem with a Vokera boiler. Hot water in the radiators, so heating is good. But when turning on a hot water tap, the boiler doesn't fire up and the water doesn't heat. No sign of a water leak, and no loss in pressure either.

Any ideas?

Steve, October 2007

When you turn on the hot bath tap does the pressure gauge on the control panel of the boiler go to zero?. What does the gauge read when the hot taps are off?.

c, October 2007