Baxi combi 105he boiler. 3 years old. The 50* error LED flashes. (fault in flue or fan?) It goes through the startup routine but the boiler will not light.It then has to be switched off for 3 hours to cool down before the boiler will light again. Also, the C/H pressure ran OK at 1bar until 2 months ago, Now, it may light at 1.8bar, but prefers 2bar, even so it will fail within 10 hours running. When set to 2bar the guage will increase to 2.8bar when the system heats up!. I have checked that the condensate trap drain is not blocked or frozen.

Peter Jay, January 2010

Always have the overflow pipe draining through the internal property bathroom, kitchen etc. Never vent straight outside if the temperature fall below freezing you will have no end of problems with sensitive electronics of the boiler.

david, January 2014

I have had same prob since before Xmas. Now and again was starting on reset. Had a service (clean out), no good, now had a new air pressure switch fitted and nothing, will not even reset. No HW or CH will not even fire up.Seems to be mostly when cold temp outside. I am thinking maybe this overflow or trap maybe frozen. Where is it? I was told clean Venturi, check plastic pipes, maybe pressure switch failing, pcb.

Nacol, January 2011

Hi guys - did any of you get to the bottom of the problem ?

I've got the same problem and its very frustrating.

I hope you may be able to help ?

Cheers

Markod, March 2010

I have exactly the same problem, The Overflow of the condensate trap is NOT blocked or Frozen but if I drain the condensate trap it starts working, but this oly lasts for a short time. Turning the Hot water on tends to make the fault occur but only sometimes, I am still looking for a solution.

John Thom, February 2010