ideal icos HE15 flame error

[martinjjones]

My ideal ICOS HE15 boiler keeps coming up with a flame error when set to a boiler temperature above mid way. When set low it never (well once actually) comes up with the failure. The boiler has been serviced recently and had the spark electrode replaced and that did not cure the problem. The condensate trap is clear. When I press the reset (when the boiler has cooled down) it always relights but fails later on when warm. I don't beleive its going out but fails to light when heat is called again.

Its strange that it only happens when warm. Any ideas. I don't want to call out another engineer who will simply replace parts, I need a good diagnosis first. If all else fails anybody know and good guys in the derby area who can help. The ideal helpline just say call a man out !

 

[twgas]

Although the trap may be clear, is the condensate pipe ok, may be backing up over a period of time, then draining out while its locked out/cooling down so will relight again. If this is the case the boiler may not be running long enough, when its on a low setting, to fill with condensate.

 

[gas4you]

If nothing else points to L:F, I usually replace the flame detection electrode.

They can appear to be ok but fail when working for some strange reason.

 

[martinjjones]

Thanks for the suggestions. I'll try and look at the condensate pipe but its buried in the wall and not sure where it terminates. Guess flushing down some water will tell ? Then I'll try a new detection electrode.

 

[martinjjones]

Flushed two litres of water down and no problem, the water went down the pipe without any apparent blockage. Repeated and still no problem. Turned to boiler back on, set it to warm, it all fired up and when it shut down after twenty mins it it failed to relight when called again. I think it may even have have lit so perhaps it is the flame detector playing up when it gets hot. No other errors are indicated.

 

[martinjjones]

Replaced the detector electrode. Problem does not seem to have gone away and if anything its more unreliable than before. Any ideas on what to change next ?