Booming Boiler!!!

[SamBrown]

Hi, I have a Potterton Prima 30B boiler and all was well untill it had it's yearly service. After that, half the time it starts up OK (with a nice blue flame) and the other times it starts up with an orange flame and a 'booming' noise - (like it's not getting enough oxygen?).
I called him back and he said it's fine and nothing to worry about. It's shaking the house and making the wife/kids cry !!!

Any ideas please.

thanks

 

[oilman]

You have a reasonable point in that it appears to be low oxygen. This condition can give rise to high carbon monoxide. Have you got a copy of the combustion results?

The gas experts here can tell you more detail of what the symptoms mean.

The approach I would take is possibly to invite the guy back, and suggest the trading standards department would get to know if he didn't sort it.

I had a call-back the other day on an oil boiler with similar symptoms, as something had moved a couple of days later. As soon as I heard the symptoms I knew what the problem was, and the answer, and sorted it. This had never happened to me before so it was not a common problem.

Whoever did yours should be able to sort it quickly, and if he thinks it's ok, the manufacturers certainly wouldn't. They wouldn't send it out like that, and all boilers should always be working almost as if they had just left the factory. If they don't they need fixing. Which is why we have work.

 

[SamBrown]

also, sometimes it starts with a 'BANG' and then runs OK.

I cann't (and I don't think he can) understand why it's only about half the time it happens. If it where a setting (like gas pressure) wouldn't it happen every time?

 

[ChrisR]

Sounds like it could be the gas valve not opening properly. Not sure if you mean it's just the pilot(initial lighting) which misbehaves. Could be a partial blockage. Any gas fitter who is wide awake could monitor the gas pressure at the boiler, volts on the valve, and the flame - if it does it while he's there the fault should be obvious.

Transco have been putting something (glycol I think) in the gas in some areas which has caused some makes of valve to stick, but they usually just refuse to open.

 

[SamBrown]

thanks

the piolt light is on all the time. it's just when it 'fires' up. some times theres a big 'boom', sometimes the whole unit 'rumbles' and all the flames are 'orange' not 'blue' and sometime it works OK.

 

[Plumber Will]

Sounds like it is an "exploding gas valve" which means it is sticking to a point where pressure will open it fully.get the guy back he should have spotted this. Or get another opinion from another corgi guy!

 

[DP]

Orange flames have nothing to do with lack of oxygen. You have indicated that the flames are blue when no bang occurs, but yellow when it comes on with a thud. Explosive ignition is dislodging dirt particles within the combustion box which give the flame orange colour. You will find the flame goes blue after several seconds (if my theory is correct). Your guy wants to check the burner and interconnecting pipes to the burner. It is possible that the gas is escaping elsewhere to collect as unburnt pocket of gas, size of which gets larger until ignited. Bigger the pocket, bigger the bang.

 

[ASALMON]

the pilot light is on all the time. it's just when it 'fires' up. some times theres a big 'boom', sometimes the whole unit 'rumbles' and all the flames are 'orange' not 'blue' and sometime it works OK.[/quote]


I have the same problem with a Myson Apollo propane 50/65.
Some times the burners do not all light straight away. Symptoms :-

1. just LH side of front burner (closest to pilot light)
2. first two rows light
3. middle section of front burner "jumps" up and down

Boiler was serviced about 5 months ago.

Sticky gas valve sounds possible.

Is there any easy way to check/cure this?

 

[sterose]

Are we talking about a 'detonation' boom or a 'low-frequency whoosh' boom?

My boiler 'whooshed' for years (before it was replaced) and I never had a problem...

 

[DP]

Asalmon- get your boiler checked by a CORGI engineer who has Boiler ticket. You have flame lift- this should be investigated.

Sambrown. Have you made any progress?

 

[bradleybear]

It sounds like the flue is not intact. A common problem is recirculation of products of combustion (fumes) due to a hole in the inner flue, or the flue becoming loose. Instead of fresh air being burned, the boiler is burning co2, hence banging, flame lift from the burner, orange flame picture. Get it checked out.

 

[breezer]

the boiler is burning co2, .

shouldn't that be CO not CO2, since CO is carbon monoxide (same density as air, lethal and will burn) and CO2 carbon dioxide, ( heavier than air, lethal, and puts out fires)

see

 

[ollski]

sorry breezer 1 part methane + 2 parts oxygen go in and 1 part co2 and 2 parts water come out. the problem starts when the combustion air is filled with co2 which will then result in incomplete combustion and hence co!

 

[sterose]

See if the flames are burning with a very orange colour, or are mostly blue.

If it's orange, you got a problem.

If it's blue, no problem for you.

Ha! that last bit rhymes....

 

[bradleybear]

ch4 + 2o2 = co2 + 2h2o thankyou very much you rodney