I have a worcester 28i junior combi boiler which will not spark the pump runs, the fan runs which in turn switches the air pressure switch but as soon as this switches the red light on the front of the boiler starts to flash once per second the fan will then run for a little while longer then switch off i have already changed the pcb anyone got any ideas thanks for your time

daz wacky, March 2010

Hi. This is a common fault on these boilers. They will spark for 3 seconds the lock out. The problem is the low water pressure switch located at the top right hand side of combustion chamber. Easy to check by just linking out the switch but remember to remove the link

Colin, February 2011

It will be the water pressure switch it will be blocked or faulty you can bypass it electrically and this will sort out the problem

the plumbing doctor, March 2010

Hi

Know exactly how frustrated you might feel. Had the same problem. First of all fan was replaced, but every time cover put back on it light would flash again. Then a new circuit board was added (almost £200). This was then found to be faulty! A new board has since been added. So far no problems, but apparently combi boilers don't have as long a shelf-life as older ones. Hope this helps somehow, also check for any small plastic parts which need replaced due to melting.

Jeannie, March 2010