I'm having problem getting my baxi solo 3 pfl range boiler to run. I've managed to get it to fire up if it's been left a while but it only stays on for about 5-10secs! I'm starting to think that it could be caused by the 3 way valve because when i select HW it moves into position and the constantly clicks as if it is not reaching the end of it's travel (mabee jammed?). Is this a normal sound and if not, what is the solution?? Could there be another cause?