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Discuss Firebird external oil boiler locks out when cover is on. in the Oil and Solid Fuel Forum area at PlumbersForums.net

Hi All,

I have a Firebird Enviromax external oil boiler, it has a Riello RDB2.2 C26 burner which keeps locking out.
It has been an ongoing problem, where I've had to call my local guy several times. He gets it going, but it doesn't stay working for long. Its costing me a fortune for his time.

I'm beginning to see a pattern. When it locks out, I remove the side cover, press the reset button and it fires up okay. I can stand there watching it for a good 10 to 15 mins, working fine before I get bored. As soon as I put the cover back in place, it locks out again within about 10 seconds or so.

I wondered whether its restricting the air flow. The vents are not blocked, but I've experimented with just leaving the cover balanced against it, with a good two to three inch gap, it seems to work for a while, but will lock out a while later.

Its peeing down outside, so I don't really want to leave the cover completely off, and expose the electrics to the rain.

Any suggestions of what the issue might be?

I was wondering if the thermostat might be playing up, and that leaving an air gap keeps it cool. But it does seem to be the burner playing up, rather than it being told to go off.

I'd very much appreciate any wisdom or theories, or things to try.


In this situation it's usually failed chamber seals leaking products of combustion into boiler casing. With the case on little to no clean air is pulled in and the flame is lost.


Unfortunately this is not something you can fix yourself and I will get to why in a minute.
First, you need a new engineer because the problem you're experiencing is quite common and any engineer worth his salt should of considered what I mentioned above on first visit.
I can't be certain for sure it's chamber seals, or flue seals, condense trap failed (if condensing boiler) etc that have failed but that's exactly where I'd start looking and any engineer should have a flue gas analyser and using that would of easily proved if something had failed.
Now, why can't you fix this? Technically you could, beit a door seal, rope seal or a bit of fire cement, however boilers combustion needs to be set with the boiler casing on, which means the engineer setting up the burner needs a flue gas analyser, which you don't have. You could try and fix the initial problem and probably would but you would be unable to leave the burner running in such a state that it burns efficiently, cleanly and safe.
I suggest finding another engineer because it shouldn't take someone multiple visit to rectify a problem which can only be down to a few things. If need be go on the OFTEC website and search for technicians in your area, alternatively say whereabouts you are in the country and one of us few oil engineers on here might be able to help.

John Coen

I have experienced this with an early gerkros condenser fitted with a bentone burner. All seals were intact. Half of the baffles in secondary heat exchanger had been left out, I presume by the manufacturer, as I was the first to open combustion chamber. My reasoning suggested there was too much resistance throughout flue.

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