My Vaillant Ecomax 824 Combi-boiler is showing the error code F22 and it's not producing any hot water or heating.
Any ideas?

Tim Metford, December 2009

Thanks, wirecutterman, you're right about the pump, the expansion vessel seems to have been leaking and the pump's not working at all now - methinks it's time to call in the boiler repair man fast before I freeze!
Tim

Tim Metford, December 2009

I have one of these boilers,the code is listed as below
Code = Meaning
F 22 = DRY FIRE
Causes (thinks to be checked according to manual )
Too little water in appliance.water pressure senor defective,cable to pump or water sensor defective , pump blocked or defective , pump output to low.

All you can do is check the pressure gauge if on 0 or low refill the system via the filler loop to 1 -1.5 bars, bleed it, and then retry it.
if o k pop head out side and check the blow off valve (P,R,V) IS NOT PASSING. if it does further investigation of the boiler is needed. especially the expansion vessel

wirecutterman, December 2009