Central Heating

Vaillant ecotech 637 pilot keeps going off 3 to 4 times a day

Anonymous user 28/02/2024 - 3.57 PM

Hi. I have a vaillant ecotech 637 system boiler 7 years old. Last 6 weeks the pilot light goes off and I have to press the pilot button to restart pilot. It runs for a few hours and then goes off again. I get error code F54 and F29 every Time. Some times it is F54 and F28 code. The gas valve was changed 14 months ago brand new one and serviced twice in 14 months with no obvious problems. Last service 1 months ago when Electrode was replaced but didn't solve problem. So paid for something that was not the cause The condensate pipe connects to a bathroom waste pipe so it's not frozen pipe..this problem didn't happen for 7 years..I don't think its draught problem cos not happened for last 7 years and we have had stronger winds than now.. 1. Is it gas supply problem cos I have a 22mm gas supply/pressure into boiler. 28mm pipe from meter for about 7metres and then 22mm for about 12metres into boiler with 7 bends elbows?.. 2. is it gas valve again? How can that be tested? 3. Is it pcb? But it works after reset and then goes off again after 4 hours or so? 4. Is there debris in the pipe from gas valve to pilot? 5. Is it gas isolator closing and then opening after reset Or? 6.Or anything else? Don't want a trial and error fix cos it will cost me eveytime without knowing the cause..any help will be appreciated to pin down cause or to eliminate something from your experience..Many thanks