Boiler ignition problem

[Soliton]

I have a Ideal classic FF350 boiler.

It has just started having problems on initial firing. The pilot lights and the main gas burner ignites. The flame is somewhat spluttery and it has a yellow hue. It splutters for a while with occasional stop and re-fires. It also sometimes has the ignition spark repeating. This only happened when the boiler is started from cold. It takes about 3-5 minutes to settle onto a steady blue flame. If it needs to turn off an on when warm/hot during normal running the re-firing is fine, so it only seems to be a problem when cold.

My only thought was some debris has fallen down into the gas burner. It recently had a new fan fitted so thing could have been disturbed.

Any suggestions.

 

[Dan Robinson]

Sounds like a good service is needed.

Has something blocked the flue?

 

[Soliton]

Just had a quick look. Can't see anything blocking the flue.

I can see that the inner pipe in the flue has dropped a little and is not held in place by the outlet nozzle on the outside of the house. It could be that this happened as a result of the fan being fitted. I expect I can fix that but it shouldn't cause the problems I'm having, should it.

Would you expect a service to fix it? If it could need a parts replacement, which one, I need to gauge what is the possible damage (£s !!)

Thanks for your help.

 

[gas4you]

I can see that the inner pipe in the flue has dropped a little and is not held in place by the outlet nozzle on the outside of the house. It could be that this happened as a result of the fan being fitted. I expect I can fix that but it shouldn't cause the problems I'm having, should it.

Thats your exact problem.

I always drill and fix a self tapper to the flue terminal outside, so the inner flue is held in place before I work on a classic.

Your boiler is sucking in it's own fumes, hence not lighting properly. I'm surprised it works at all.

Put the inner flue back correctly and all should be well

 

[Dan Robinson]

Well if it has dropped at one end it means it might not be a good fit at the other end meaning the boiler is not burning clean air and could be classed as dangerous.

A service would pick up on this, but what is required by way of a repair depends on why the flue is not in the correct place.

 

[gas4you]

The inner flue will drop out about 90% of the time when removing the fan on classics.

It is caused by the tight fit of the inner flue on the fan connector.

The inner flue is telscopic at the boiler end and often the inner flue is not extended enough to fit back into the exterior flue terminal end.

Hence why I drill and self tap before anything else. Holds it in place and gives me something to pull/push/twist against when re-fitting the fan after service

 

[Soliton]

Been to fix the pipe. It was fastened ok at fan end just not supported at outlet nozzle end. Couldn't extend the pipe in situ so took the nozzle off, released it from the fan and extracted the whole pipe from the outside. The two parts wouldn't slide over each other until I gave it a spray of wd40, that freed it off. Looking at the fan end it looked like it had been hit with a hammer in a few places so used some grips the repair/reshape the damage. Fitted it all back and it is now supported at both ends.

Fired up the boiler and yipee - a nice steady blue flame. OK it wasn't as cold as it would have been first thing this morning but it wasn't warm to touch so I'm hoping it will be fine now. I'll double check the first fire tomorrow morning to be sure.

Thanks for your help guys. It is much appreciated.