Indoor grant boiler problem

Darwin

A little background to my problem - we have an indoor Grant boiler that is just 20 years old now. It has been serviced annually without fail and various parts replaced over the years including a new burner and new circulating pump. Last year the ignition on the burner started a cycle of cutting out and re-igniting - typically it would run for a minute then cut out (with the pre-ignition sound still happening), then restart and continue like this. My service guy didn't really have time to look at it, so we disconnected the hose from the burner and that fixed the problem and it was left like that for most of last winter. I had it serviced again recently and it appeared to be running fine, but the next day it reverted to the same cutting out cycle. Again disconnecting the hose/flue from the burner fixes the problem. This hose has never been replaced, could it be something related to this? It might suggest the burner is getting starved of air, I just don't know. Any suggestions most appreciated!

jimf

it sounds like the seal on the balance flue is recirculating flue gasses back to the burner

by disconnecting the hose you are then taking fresh air from the room

wind blowing and holding the flue gasses around the discharge could also cause the same issue

Darwin

Thanks very much for the reply, I've arranged for my service contact to come back and will suggest looking at that issue.

Darwin

Hello again, my service engineer never really got to the bottom of my boiler issues. The hose/flue has been left disconnected since August. Lately, it is behaving this way:

1) On startup from cold, the motor runs but the ignition cuts in and out every 10 seconds or so. This cycle continues for about 40 minutes until the operating temperature is achieved.

2) After this the symptoms change. The boiler generally runs ok, but between the normal start/stop cycles, the ignition takes typically anywhere up to a minute (sometimes longer) to come on but does stay on until the next stop/start cycle.

I had a similar issue about a year ago and we went through a batch of photocell sensors as some of them were bad. The oil pressure was checked at the pump and it was ok at the time.

Does it sound like a fuel starvation problem? The filter at the oil tank has never been cleaned. Does the fuel pump itself have a filter that could possibly be clogged? Thanks again for any advice - I will pass it on when my engineer calls again.

Wearb

Darwin wrote: »

Hello again, my service engineer never really got to the bottom of my boiler issues. The hose/flue has been left disconnected since August. Lately, it is behaving this way:

1) On startup from cold, the motor runs but the ignition cuts in and out every 10 seconds or so. This cycle continues for about 40 minutes until the operating temperature is achieved.

2) After this the symptoms change. The boiler generally runs ok, but between the normal start/stop cycles, the ignition takes typically anywhere up to a minute (sometimes longer) to come on but does stay on until the next stop/start cycle.

I had a similar issue about a year ago and we went through a batch of photocell sensors as some of them were bad. The oil pressure was checked at the pump and it was ok at the time.

Does it sound like a fuel starvation problem? The filter at the oil tank has never been cleaned. Does the fuel pump itself have a filter that could possibly be clogged? Thanks again for any advice - I will pass it on when my engineer calls again.

I would like to see the combustion printout from service engineer's last visit. Do you have it?

This boiler sound like it's not setup correctly.

Darwin

He did give it to me, but I'm afraid I can't find it now. He did mention it had lost its settings when replacing the photocell last time. I'm just wondering would a new burner solve the problem - I don't mind the cost and I'm so sick of it as this stage.

Wearb

Darwin wrote: »

He did give it to me, but I'm afraid I can't find it now. He did mention it had lost its settings when replacing the photocell last time. I'm just wondering would a new burner solve the problem - I don't mind the cost and I'm so sick of it as this stage.

A decent service guy would cost a fraction of that.



Even a new burner needs to be adjusted for the boiler that it's installed in.

Darwin

Ok thanks, I'll see what the prognosis is tomorrow. My service guy is very experienced and installed my current burner about 7 years ago. All my problems seemed to start when the original photocell failed and subsequently replaced.

jimf

could be something as simple as been over aired especially when cold

the air density at the moment would make a difference

where are you based as i wouldnt be very confident in your service eng especially if he said changing the photo cell would change the combustion settings

maybe somebody on here might be local to you and give it the once over

new burner would be a no no for me