lock out on sterling 40 boiler

[Locko]

Been out to a sterling 40 burner which goes to lock out, I have done all the checks on it. Replaced the solenoid, capacitor but last night the boiler locked out when I was there. I think the motor might be on the way out, it was quite noisy when the burner was starting up. Do you think this is right or can anyone help?

 

[Agile]

I wonder what checks you have done?

If its a flame failure lockout then either its failing to recognise the flame or the flame is failing!

Which of those did you observe?

Tony

 

[Burnerman]

The motor should be quite quiet...if it isn't suspect the motor bearings or the drive shaft that takes the drive to the pump. Check that the motor is spinning fast - about 2700 RPM. If its easy to turn the shaft by hand it should be making this.
John

 

[Locko]

When the burner is running she is running well. When the burner gets to the correct temperature and then goes to restart it is at this point that it makes a grinding noise as if the motor trys to kick in but cant and then goes to lockout. The customer has to then wait until the motor has cooled right down before he can start it again.

 

[Burnerman]

It looks like the motor then - see if it can be spun by hand easily, and check its wiring connections in the control box for tightness. Is the oil pump smooth to spin?
John

 

[Locko]

Thanks all will check these this evening and let ya know how I get on.

 

[Burnerman]

Aye, report back if you will, mate.
John

 

[Agile]

From what you say you will have to feel the motor/pump shafts when its hot as thats when the problem seems to occur.

Tony

 

[Locko]

Tried new motor - not that. Will not fire when boiler warm. Shaft possibly a bit stiff. Do you suggest it could be the pump???? Burner fires up lovely from cold only!!!!

 

[Tibbot]

Tried new motor - not that. Will not fire when boiler warm. Shaft possibly a bit stiff. Do you suggest it could be the pump???? Burner fires up lovely from cold only!!!!

Have you checked the pump for tight spot, condition of drive dog and observed pump pressure gauge for smooth oil flow during start up?

 

[Burnerman]

Did you use a new motor capacitor or a second hand one?
Double check the drive dog(s).
John

 

[Locko]

I assume the drive dog is the shaft. This is ok. Tried new motor with capacitor.

 

[Locko]

Tried new motor - not that. Will not fire when boiler warm. Shaft possibly a bit stiff. Do you suggest it could be the pump???? Burner fires up lovely from cold only!!!!

Have you checked the pump for tight spot, condition of drive dog and observed pump pressure gauge for smooth oil flow during start up?

I feel that the pump was tight and i Haven't yet observed the pump pressure gauge for smooth flow oil but will definately check this tomorrow. Thanks

 

[Tibbot]

Tried new motor - not that. Will not fire when boiler warm. Shaft possibly a bit stiff. Do you suggest it could be the pump???? Burner fires up lovely from cold only!!!!

Have you checked the pump for tight spot, condition of drive dog and observed pump pressure gauge for smooth oil flow during start up?

I feel that the pump was tight and i Haven't yet observed the pump pressure gauge for smooth flow oil but will definately check this tomorrow. Thanks

No, not tight, tight spot. When saying you were 'out to a Sterling 40' assumed you're working for a customer.

 

[Locko]

Aye, report back if you will, mate.
John

Thanks for all your help. Replaced the pump working beautiful. Thanks again