Flame failure after draining system

[Sedgley2004]

Hi
I drained my heating system to replace a radiator and now ive got flame failure on the boiler (potterton promax fsb he). I've repressurised it and bled radiators. Any ideas?

 

[SimonG]

Probably over heat, will be air locked.

 

[Stu-B]

Does it light then go out or not light at all

 

[Sedgley2004]

It lit for a few seconds then went out. I had a play with it and eventually it works. I'll guess it was an air lock. I've got a few radiators to replace so it's gonna be fun and games

 

[Stu-B]

Normally when a boiler overheats it makes strange noises, some hiss some bang and clatter, any of those? Often the aav is nipped up and air gets trapped in the back of the pump.

 

[centralheatking]

It lit for a few seconds then went out. I had a play with it and eventually it works. I'll guess it was an air lock. I've got a few radiators to replace so it's gonna be fun and games

If it is getting air locked shoot it up with mains pressure after you have finished. Connect hose to outside tap and to the lowest drain off with a jubilee clip. Gently switch outside tap not full on open drain off and check for leaks. Open bleed on bottom rad increase pressure and blow air out working upwards and away from induction point. Close off drain off. If you can see any aav tickle them whilst doing rads. Centralheatking