Danesmoor 20/25 won't fire up

[Paul_Robert]

Boiler has been idle for a while and won't fire.

Pump runs but then goes into lockout as it won't light.

Old feed from the tank seems fine but there's no oil at the burner.

Solenoid measures about 2.7k ohms
However, if I put the meter on the connector to the solenoid it doesn't seem to get any power. Pump runs for say 30 sec and then boiler goes into lockout and at no time does the solenoid get any power - hence no oil at the burner ??

What would stop power getting to the solenoid ?
Control box is Satronic TF830B
Is there any way I can test further or do I just have to get the control box replaced ?

I thought about hot wiring the solenoid to a mains feed and switching that on a few seconds after the pump starts just to test if that is the issue. Is that a sensible thing to do ?

Cheers for any help or suggestions.

Paul

 

[oilhead]

Do you get a spark
whilst the burner is in prepurge? If not you may have a faulty photo cell giving a false flame signal. Disconnect the P/cell and try again. If it lights, then locks out, replace the P/cell. Otherwise, try new box.

 

[Paul_Robert]

OK, will try that. So if the photo cell is faulty could it stop the solenoid from getting any power ?
I guessed the photo cell would only come into play once oil was reaching the burner and had time to light up.

 

[oilboffin]

No the first thing the photocell does on startup is to register dark to enable the control box to continue with start up procedure,which is why when disconnected the burner may fire.Bob

 

[Paul_Robert]

So I unplugged the photocell - boiler fired up, ran for a few seconds and then went to lockout. Just as expected.

So I thinks photocell is dead.

I took it out and it seems fine when tested on a meter. Very high resistance when dark, few hundred ohms when light.

Put it back, boiler won't fire. Unplug it, boiler fires then stops.

I've decided to replace it anyway but seems really odd that when tested on the meter it seems fine.
It has near O/C resistance when dark but seems to prevent the control box firing up the boiler when plugged in.
Wiring is all fine and tests out ok.

I guess the control box is putting 240v across the photocell whereas the meter is very low voltage so perhaps it's breaking down under high voltage.

Fingers crossed a new one sorts it out for good.

 

[oilboffin]

It's all magic put a new cell in it smear yourself in peanut butter and howl at the moon and it should work.Bob