Lock out on Sterling Burner Heating World Grandee Combi

2 Nov 2006
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United Kingdom
We have a Heating World Grandee Combi boiler with a Sterling burner. The burner locks out once a flame is established.

After 2-3 resets the burner fires up and continues fine until it automatically stops. When it the boiler calls for heat again the burner starts again for a minute or two then locks out.

We get it going again but this always happens.

The boiler was serviced three weeks ago and has been working well until the weekend. The flame is clean and we have lots of oil.

Any ideas please?
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My first idea would be to call back the person who serviced it to diagnose the fault, but, before you do that, have you inspected the in-line oil filter?
The guy can't make it until later this week. I just wondered if I could do anything in the meantime to get hot water and heating. The in-line filter is clean.

Would it hurt to reset the lock out switch (works on the 2nd or 3rd reset) every time to get it working for a short period?
You could be drawing in a bit of air. Were the hoses/hose changed in the service?

It's unlikely to be the photocell because it runs once the pump is cleared.
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sounds familiar.....service a perfectly running boiler ...and then it all goes
t its up ....

could be anything. sorry to be so helpful. :LOL:

actually...undo the allen screw and take plastic cover off and check photocell is clean, might be sooted?
Thanks Wilhelm I'm going to have a look at the photocell now. Simond the hoses weren't changed in the service.

Why does it have to happen in the winter when we have no other form of heating or hot water!

I wonder if Oilman is reading this only I think he knows alot about Heating World Grandee Combi's and Sterling burners from looking at previous threads?
It could be the combustion adjustment is giving too much air. However measuring the value of the motor capacitor might be interesting
oilman said:
...measuring the value of the motor capacitor might be interesting
Mm, yes. Especially if you know what the value should be for that particular motor. ;)
You've missed my point, but it was quite a subtle one.
So subtle it was pointless. Why not state something plainly?
Not pointless from my point of view. And plain isn't always fun.
But it's more trustworthy. I doubt you play these games with your customer's invoices, or quotations for that matter. I don't see where your comment has helped the OP.
Thanks Oilman for all your help. I'll keep you posted on the outcome. Not sure if it could be an electrical fault as the water pump always stays on after lock out.

Do any of your customers have much trouble with Heating World Grandee Combi's? We find you have to turn the thermostat right up to 5 or 6 to maintain the heating. The thermostat calls for heat but it takes ages to kick in every cycle.
These boilers are not generally a problem.

The water pump staying on has absolutely no connection with the burner locking out. Same as saying "Um, cant be the kitchen light cos the dining room light works".

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