Oil boiler causing circuit breaker to trip

Kashkai

Our 2 year old Firebird oil boiler didn't start up this morning so I had a look at the circuit board and the breaker for the boiler had tripped. I reset it and restarted the boiler but after a couple of minutes it tripped again.

I went outside to the boiler and removed the cover and inspected it. The "bottlecap" (a pressure release valve I believe) was leaking but the water was flowing away from the wiring so I doubted that this was the cause. However I called a plumber, described the problem and he called out (while I was out - it was the wife who dealt with him) replaced the bottlecap and dried everything off and retried the boiler and it ran fine (so he said to me on the phone) so he turned it off. However, an hour after he left, I came home and turned on the boiler again and after a couple of minutes, it tripped again. I rang this guy and he said it was an electrical fault and I should call an electrician but he still wanted his money (my wife hadn't paid him).

So does anyone know what the problem might be and am I right in thinking that this guy has a cheek looking for money when he didn't fix the problem.

davelerave

You could maybe try the pump on its own if it comes on with boiler.Depending on the setup.

Kashkai

I tried the pump on its own and it works fine so I still think its a problem with the burner itself.

meercat

try resetting the high limit switch.its beside the thermostat controls on top of the boiler.usually unscrews and press red/black button and listen for click.if thats it there is more of a problem.get back on and i will give more info.

davelerave

i would do a visual check first on burner and leads is it's tripping mcb.i'm gone rusty on the internal burner wiring -afraid i would have to refresh my memory first

jobfix

Hello. Your plumber changed the pressure valve but did he tell you why and what the course of the problem was. If he did the job in halve an hour ( ask the wife) he DID NOT replace it. Did you check if the burner was running before tripping the switch. If so then there is an electrical problem with an earth wire ( frost thermostate , regulating thermostate etc) If not then it could be that the burner is stuc (oil pump or motor)
I would not dare to ask for money when i did not fix the problem, i would go back and fix it or give advice on what to do next. I wonder why he switch the boiler of while your wife was at home?

Kashkai

I was stumped for a while until I took the suggestion above and ran the pump by itself for a while (longer than I previously had - must be more patient!!) and hey presto, it tripped the circuit breaker (I had been convinced that as it was spinning freely, the pump was working fine). So I bought a new pump and fitted it (10 minute job) and now working perfectly just as the cold weather bites phew!!

Thanks for the advice Davelerave. Another useful piece of info to add to my DIY knowledge

davelerave

On an 'rcd' protected circuit it prob would have tripped immediately.

Kashkai

Thats what had me stumped for a while as the burner would ignite and run for about 2 minutes before cutting out (with the circuit breaker tripping) and so I presumed it was some kind of faulty thermal cutout on the boiler or a short circuit in the wiring between the house and the burner. If the circuit breaker had tripped immediately then I would have looked more closely at the pump initially but I took the chance of replacing it and its worked fine since.

davelerave

i would test circulating pumps first with 'megger' if heating is tripping

Kashkai

The circuit breaker tripped again yesterday morning but the boiler had been, and is now working fine again. Perhaps a test on the wiring is required. Where do you get a megger to test for breaks in the insulation of electrical wiring or is it strictly a test for professionals only to carry out?

Ba$tard

Hi there

I have exactly the same issue, well symptoms as you...when starting the heating, the downstairs sockets circuit would trip.

Firebird also, about 15 years old.

The problem was the fact that the frost stat (about €30) was sat in water in the fire hut. The water was caused by two leaks
First leak was in the air vent on the top left of the boiler - notorious for failing/leaking.
Second leak was the water valve before the water pump - again notorious for failing/leaking.

I got both the air vent and valve swapped out (system drained) and I replaced the frost stat myself (which was completely blow - ie side of housing by transformer, relay & cap blown out).

So, now I have fixed the frost stat to the inside of the fire hut with sticky velcro. All fixed.

Take a look at your frost stat (with the respective circuit switched off) (as it is always live)

Hope this helps.
James.

davelerave

Prosperous Dave wrote: »

The circuit breaker tripped again yesterday morning but the boiler had been, and is now working fine again. Perhaps a test on the wiring is required. Where do you get a megger to test for breaks in the insulation of electrical wiring or is it strictly a test for professionals only to carry out?

If it's the boiler 'mcb'?? that's tripped again you may not have found the original problem.
An insulation test on pump would have confirmed.

If it's a dedicated circuit(non-rcd protected ) i'd prob do a L-E test on fixed wiring and a visual check for problems (assuming boiler is ok)

Kashkai

Ba$tard wrote: »

Hi there

I have exactly the same issue, well symptoms as you...when starting the heating, the downstairs sockets circuit would trip.

Firebird also, about 15 years old.

The problem was the fact that the frost stat (about €30) was sat in water in the fire hut. The water was caused by two leaks
First leak was in the air vent on the top left of the boiler - notorious for failing/leaking.
Second leak was the water valve before the water pump - again notorious for failing/leaking.

I got both the air vent and valve swapped out (system drained) and I replaced the frost stat myself (which was completely blow - ie side of housing by transformer, relay & cap blown out).

So, now I have fixed the frost stat to the inside of the fire hut with sticky velcro. All fixed.

Take a look at your frost stat (with the respective circuit switched off) (as it is always live)

Hope this helps.
James.

Hi James,

Like you, the air vent in my boiler also went about 2 months ago (I replaced this myself at the time) and was letting a steady stream of water cascade down onto the boiler. In addition, the foil backed insulation on the roof of the boiler casing somehow became dislodged and fell onto the top of the boiler and soaked up the water with the result that this fed a small flow of water over the electrics until I opened the boiler cover and found this problem. It might have interfered with the frost stat (I didn't know there was one to be honest) so I'll google the specs on this boiler and find out exactly where it is and see if there's a way of testing it for damage.

Thanks for the heads up.

Regards

David