Greenstar 18/25 boiler

Johnj6922 · 16 Jan 2021

Hi All

I have the above boiler with a sterling 50 burner which will not fire.

it seems to try to fire and sounds like it does for 10 - 15 seconds then locks out. Plenty of oil in tank.

I have replaced the photocell but still no go

Any help will be greatly appreciated... thank you

John

ericmark · 16 Jan 2021

I have had the problem now for 18 months, only just cured, the guy repairing it for me was using one item at a time, but fault was intermittent so it was hard to know when fixed, but he listed a number of things.
* Photocell not seeing flame.
* Flue leaking and CO2 snuffing out flame.
* Transformer not working (I would have called it an ignition coil).
* The fuel valve coil failing.
* The fuel valve sticking.
* The relay box faulty.
The list goes on, and I tried to help isolate the problem, once running it was OK it only failed to start, and once cool it started OK, in my case it turned out to be the transformer, but unless you can be sure, you can't really order all the parts just in case, and the oil boiler man carried the spares on his van, so it is often better to get some one in to repair it. My repair man is far quicker than ordering bits on internet, and his ears are better tuned than mine.

Johnj6922 · 16 Jan 2021

ericmark said:
I have had the problem now for 18 months, only just cured, the guy repairing it for me was using one item at a time, but fault was intermittent so it was hard to know when fixed, but he listed a number of things.
* Photocell not seeing flame.
* Flue leaking and CO2 snuffing out flame.
* Transformer not working (I would have called it an ignition coil).
* The fuel valve coil failing.
* The fuel valve sticking.
* The relay box faulty.
The list goes on, and I tried to help isolate the problem, once running it was OK it only failed to start, and once cool it started OK, in my case it turned out to be the transformer, but unless you can be sure, you can't really order all the parts just in case, and the oil boiler man carried the spares on his van, so it is often better to get some one in to repair it. My repair man is far quicker than ordering bits on internet, and his ears are better tuned than mine.

thanks this is a pretty long list! Was hoping it was going to be something common, not sure I want to throw a load of parts at it..

Terrywookfit · 16 Jan 2021

DOES it actually fire ??

Johnj6922 · 16 Jan 2021

It fires and runs for about 15 seconds flame sounds like it is weak but adjusting air makes no difference. I took the blast door off to see if chamber sooted up and you could feel the heat inside so there has been a flame but won’t stay lit.

ericmark · 16 Jan 2021

My hearing not as good as the oil man, But I can hear some things happening.
So at start we have a purge time, a fan seems to run.
Then the solenoid opens and the transformer causes a spark. He can hear the spark, I just hear the woof and it ignites.
And the the spark stops once all is running.

So lifting the burner out if wet then clearly the solenoid has opened but it failed to fire, but if dry then the solenoid likely has not opened, there is also of course the pump, again sound the guy uses a screw driver to work out if bearing OK etc.

I worked a lot on space heaters, and it was often a case of try it and see, with 10 space heaters I would swap parts between one running and one not running to work out what had failed, OK some times you could work out exactly what was wrong, but even where I had worked on many oil burners, I still considered it worth while getting a guy in to fix it.

Terrywookfit · 16 Jan 2021

Replace nozzle, check oil pressure, (Make sure you have no water in the oil.) First step as water don't burn well
Are you on a tigerloop system

Johnj6922 · 16 Jan 2021

Terrywookfit said:
Replace nozzle, check oil pressure, (Make sure you have no water in the oil.) First step as water don't burn well
Are you on a tigerloop system

yes I am on tigerloop, not really sure how to change nozzle and sadly don’t have tools to check oil pressure...

Johnj6922 · 16 Jan 2021

So I have taken out the photocell and reset when boiler fires I shine a torch on the photocell. Looking down the photocell housing I can see a flame which starts off really strong but peaters out after a couple of seconds. It tries to fire 3 or 4 more times with same results. Any ideas?

oilhead · 16 Jan 2021

You have fuel supply problems. Start at the tank and make sure you have oil, then move forward checking and BLEEDING any filters. Take a sample of fuel to check for water.How is the oil level in the Tiger loop? Take a look at it while you get someone else to try starting it and look for bubbles. If all is OK, move to the burner. Check the drive dogs on the pump drive. If all OK, it would suggest there is a problem with the oil pump.
One final point, if you have freezing weather, you may have some frozen sludge, but the intermediate checks of the line should show these up.

Johnj6922 · 16 Jan 2021

oilhead said:
You have fuel supply problems. Start at the tank and make sure you have oil, then move forward checking and BLEEDING any filters. Take a sample of fuel to check for water.How is the oil level in the Tiger loop? Take a look at it while you get someone else to try starting it and look for bubbles. If all is OK, move to the burner. Check the drive dogs on the pump drive. If all OK, it would suggest there is a problem with the oil pump.
One final point, if you have freezing weather, you may have some frozen sludge, but the intermediate checks of the line should show these up.

Thank you!

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Greenstar 18/25 boiler

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