DJNelsonHeating
Gas Engineer
- Messages
- 37
Hi. If anyone can help me try and pin down an issue with a customer's Potterton Promax 24HE...
I was called out to this just before New Year, as it had literally exploded (well, the burner anyway), and scared the living daylights out of the occupants who thought the front door was being kicked in! It had the old fabric type burner, which was quite dirty and clogged, and clearly the offending part. I duly replaced the damaged burner with the new ceramic type burner and also fitted the new injector pipe that was supplied with the burner. The boiler fired OK, and I left the customers with a perfectly working, serviced boiler.
However, this week I was called back, as it had worked fine for a month or two, but then started to make explosive ignition noises again, getting worse over time. I again inspected, and the burner I had installed was fine, but the electrodes were 'bent' downwards slightly, so not at 90 degrees like the sensing probe. I set these straight, at right angles to the door and set the gap, thinking that was likely the issue.
I then carried on with all my other checks - gas rate (2.33 m3h compared to 2.31 stated in the manual, so fine), fga (fine 0.0006), inlet gas pressure at gas valve (18.5mb - manual states 18.1 to 22.5, so fine I presume for the boiler to work, depsite the drop being 2.5mb (working pressure at meter was 21mb)), etc.
All looked good visually and by readings, etc.
Just before leaving it cycled back on and made (a small, admittedly) a larger than usual ignition bang, which I couldn't get it to do again. The customer DID state the explosive ignition was very intermittent, so unsure if the electrode's setting has fixed it 100%, especially as I had one loud start while I was there.
I have asked them to let me know if it continues to do it, or if fixed, but in anticipation of a call back, and me scratching my head looking befuddled, does anyone know of any other reasons why this could be happening? I understand from forums that the Promax seems prone to it, but that doesn't fix it, or allay the customer's fears of exploding boiler! I had thought the ignition PCB, but I am admittedly clutching at straws with that and don't want to replace parts that don't need it!
Many thanx in advance.
I was called out to this just before New Year, as it had literally exploded (well, the burner anyway), and scared the living daylights out of the occupants who thought the front door was being kicked in! It had the old fabric type burner, which was quite dirty and clogged, and clearly the offending part. I duly replaced the damaged burner with the new ceramic type burner and also fitted the new injector pipe that was supplied with the burner. The boiler fired OK, and I left the customers with a perfectly working, serviced boiler.
However, this week I was called back, as it had worked fine for a month or two, but then started to make explosive ignition noises again, getting worse over time. I again inspected, and the burner I had installed was fine, but the electrodes were 'bent' downwards slightly, so not at 90 degrees like the sensing probe. I set these straight, at right angles to the door and set the gap, thinking that was likely the issue.
I then carried on with all my other checks - gas rate (2.33 m3h compared to 2.31 stated in the manual, so fine), fga (fine 0.0006), inlet gas pressure at gas valve (18.5mb - manual states 18.1 to 22.5, so fine I presume for the boiler to work, depsite the drop being 2.5mb (working pressure at meter was 21mb)), etc.
All looked good visually and by readings, etc.
Just before leaving it cycled back on and made (a small, admittedly) a larger than usual ignition bang, which I couldn't get it to do again. The customer DID state the explosive ignition was very intermittent, so unsure if the electrode's setting has fixed it 100%, especially as I had one loud start while I was there.
I have asked them to let me know if it continues to do it, or if fixed, but in anticipation of a call back, and me scratching my head looking befuddled, does anyone know of any other reasons why this could be happening? I understand from forums that the Promax seems prone to it, but that doesn't fix it, or allay the customer's fears of exploding boiler! I had thought the ignition PCB, but I am admittedly clutching at straws with that and don't want to replace parts that don't need it!
Many thanx in advance.