Sterling Electro Oil Burner

[colinone]

I found burner locked out on Friday, COLDEST DAY OF THE YEAR SO FAR!! Reset but the motor just buzzed and it locked out again. I took the motor off, spun it under power and it ran. I replaced the capacitor and the burner ran OK but locked out after about 15 mins, The motor was VERY hot. This now happens all of the time but I can't find anything else logically wrong. Would the control box got to lockout if the motor was overheating?
The capacitor I fitted is rated 400vac? Wrong capacitor???

HELP!!!!!!!

 

[casius66]

When you took the motor off did you check the oil pump spindle? If it moves freely the fine, if it feels like it has resistance in it then it's likely to be knacked. Was there a rusty dust in the motor ? Bearings could be worn.
It's the microfarads you should be looking at usually 4uf.
If motor is buzzing you've changed the most obvious cause so it's going to be down to pump or motor, if it's pump you'll need the equipment to set this up and measure flue gases.

 

[Burnerman]

Is this the orange coloured burner?
The motor will get warm, but not so hot you can fry chips on it.....
BFP21 pump, maybe? I find the drive dog pretty feeble on these.
Was the motor free to rotate, and likewise the oil pump?
John

 

[colinone]

When you took the motor off did you check the oil pump spindle? If it moves freely the fine, if it feels like it has resistance in it then it's likely to be knacked. Was there a rusty dust in the motor ? Bearings could be worn.
It's the microfarads you should be looking at usually 4uf.
If motor is buzzing you've changed the most obvious cause so it's going to be down to pump or motor, if it's pump you'll need the equipment to set this up and measure flue gases.

Thank's for your advice. I took the fan motor out again and ran it on the bench in the garage for an hour. The motor wasquite cool so I checked to coupling to the oil pump. It wasn't stiff but neither was it totally free running. I put the motor back in and ran the burner again. Within 10 mins the motor was running hot again. I took the PEC out as it was running and shone a torch on it. It ran for another 10 mins before going to lock out? STRANGE!!!!!

 

[colinone]

Is this the orange coloured burner?
The motor will get warm, but not so hot you can fry chips on it.....
BFP21 pump, maybe? I find the drive dog pretty feeble on these.
Was the motor free to rotate, and likewise the oil pump?
John

Thank's for that John. You sound very knowledgable! The burner is silver and only about 4 years old. The drive dog is in good condition. The motor is very free to run and I ran it for an hour on the bench. It was very cool. The oil pump turned quite easily with a little resistance. I put it back together. It ran for 10 minutes before going to lock out again.
Cheers! Colin.

 

[Burnerman]

By shining a torch on the PEC you are effectively doing the same as the burning flame.....it sees light so that keeps the oil supply on.
One of the notorious points on many oil burners is the solenoid coil on top of the pump failing due to heat...not the guaranteed fault of course but well possible. (Its available separately, about £20). Make sure the PEC is clean too.
Your motor and pump sound ok too, so long as the motor starts up on its own, that rules out the capacitor. The pump pressure really needs a gauge screwed into the pump port marked 'P' to verify how good it is, but performance on these only tails off after a while.
John

 

[casius66]

I would start with the solenoid coil as Burnerman suggests.
Does the burner fire up immediately after lock out or does it need to cool down first? or does it buzz like it did before capacitor change?

 

[colinone]

I would start with the solenoid coil as Burnerman suggests.
Does the burner fire up immediately after lock out or does it need to cool down first?

As soon as the control box resets itself and I press the button, it carries out a short purge period then you can hear the solenoid open and it fires up right away.

Is there a high temp thermostat that sends the box to lock out?

Many thanks Casius99 and Burnerman for your advice. I really do apreciate your time! Cheers Colin.

 

[casius66]

Is there a high temp thermostat that sends the box to lock out?

- unlikely, the high limit stat will shut the boiler off not lock out the burner.

I'm still leaning towards the pump seizing, but could also be the photocell with an intermittent fault. Might be time to call someone in...

 

[Burnerman]

So, after lockout you wait about a minute, press the illuminated button and away it goes.
So, the fan should run and purge for a few seconds; then ignition occurs, oil switches on and we're in business. This is the normal procedure for these, and so far everything is ok. Then, the thing locks out again after a while. So - whats turning the thing off? Is the oil being switched off (solenoid coil fault) or does the photocell think that alls gone dark, and does the same thing? Sometimes you can hear the burner reignite if the flame fails only for a second or two.
Does the appliance run for approximately the same length of time once it starts? Obviously we are assuming that all tank valves are fully on, and filters are clean!
I think that there is an overheat stat on the boiler, but as far as I know this just prevents the burner from starting at all, rather than going to lock out, but I'm very happy to be corrected!
It seems like the hot running motor isn't an issue now?
John

 

[slapper]

pump solenoid breaking down when it gets hot,fit a new coil as suggested

 

[martineire]

As said above remove oil pump and make sure the pump shaft is not stiff and rotating ok and make sure motor shaft is ok aswell , if all is ok its prob a faulty solenoid coil, but photocell cant be ruled out either.

 

[gasandoilman]

just signed in and read this post its the coil breaking when hot,bet my last beer in the fridge...