My son has a Sabre 25HE boiler installed around 4 years ago with PCB and two thermistors replaced from previous fault. On ignition the fan starts working, and so does the pump, but I cannot get the boiler to light. If I detach the pipe to the pressure switch and blow, I can get the boiler to light but as soon as I take my finger off the end of the tube the boiler goes out.
There is no blockage in the Venturi tube kit and I can only assume that the pressure switch requires replacing.
Can anyone confirm whether I am on the right track. The boiler was working perfectly yesterday, but this morning it failed to ignite.