Trianco Eurostar Combi 90 oil boiler Failing to lockout-Help

[diylearnerA1]

Yes you did read that right the boiler is failing to lock-out.
The problem started today. Boiler has run fine all winter.
Today although the boiler motor was turning and fan was blowing air through the flue there was no heat. I switched it off and switched it on again. Burner motor running. I went outside and could feel air but no warmth comming from flue. I went back in and waited for it to lock out but it didnt. After 10 minutes I got worried and turned it off. I thought it was supposed to shut down if the photocell doesnt see a flame. It is not lighting as there is no whooshing noise that it makes when it lights and of course there is also no warmth.

I would really be glad of any help you can offer.
Many, many thanks.

 

[Tibbot]

This is usually caused by re-cycled fumes getting into air supply, causing vitiating flame which makes the burner constantly re-light, blowing the transformer and control box.

 

[diylearnerA1]

Hi Tibbot,
Thank you for your fast help.
So you think the controll box is wrecked?
I am surprised that it is recycled fumes just because it is a balanced flue model and I had an engineer reseal and check the flue 18 months ago. The flexible air hose was also renewed at this service. Do the flues usually fail that quickly?
Please could you let me know does a vitating flame make a characteristic noise?
Many thanks again for your help.

 

[Tibbot]

You only tend to get the problem on balanced flue. You can only tell by the burner cutting & relighting between heating cycles, there may be slightly extra ign noise but not much else. The flue could well be sound but somehow exhaust could be getting back down snorkel. Otherwise air setting could also be too high.

 

[Burnerman]

Control box fault I think, and usually a relay failure within.
These get a hard time if the flame is constantly snuffing out and relighting...when the burner is running, it should be smooth with a constant purr.
If you are concerned about the balanced flue, remove the flexy pipe and allow the burner to take its combustion air from within the room.
You could try Border Heating (Kingston Park) for a new control box if you don't have a preferred supplier.
John

 

[diylearnerA1]

Hi Tibbot,
Thankyou.
I am not sure as to how the exhast fumes could get back down the snorkle if the flue is good. The flue exits straight from top of boiler through a ground floor north facing wall. There are no buildings or walls or bushes it is flat for at least 30m to right and left and flat over fields for about half a mile straight out to north.
Mnay thanks again!

 

[Terrywookfit]

Get your service man to check for CO2 in the snorkel pipe.

As previously posted, The ign txfr has probably shorted due to overheating and blown the control box.

 

[Tibbot]

Try Burnerman's test for yourself.

 

[diylearnerA1]

Hi John
Thank you for pointing me towards Kingston Park!
As I have just mentioned to Tibbot Im not sure how the flue is playing up. I also should have mentioned that the seals round the baffle chamber door and where the burner fits into the firebox were replaced 18months ago if that helps. I did not notice any extra noise above the burners usual purring before the problem happened.

Can I just check, are you saying I can test for a flue problem by changing the control box and firing up with the flexi hose disconnected? If so I will do this and if it works I will get an engineer in to fix the flue.
Many thanks for all your help.

Linda

 

[Tibbot]

If you change the control box it won't fire if the transformer is blown. Also while it's been running it's probably soaked the hearth in oil so you're advised not to try to light it.

 

[Terrywookfit]

If you fit a new box on a knackaaaaaaard tranny ,You will have two scrap control boxes!!

 

[Burnerman]

Almost certainly the control box has called it a day, and the demise of this is often caused by the ignition transformer working overtime, due to the burner flame constantly needing reigniting.
Of course we can't absolutely tell if the flue is at fault.....if there is too much air entering the burner, the flame can be blown out and its only an accurate flue gas analysis that can check this for sure, together with a check on the fuel pump pressure.
John

 

[diylearnerA1]

Hi Tibbot
Now that is why I turned it off- because I was worried about it pumping oil into itself. So there is no saftey feature to stop it doing this?
Right if its full of oil I will leave it well alone.
One small point though- I cant smell any oil...
Thanks
Linda

 

[diylearnerA1]

I send a giant Thankyou and a big hug for all your help-
You have convinced me to call out an engineer-
I will let you know how it goes.
Best wishes
Linda

 

[Tibbot]

Because the control box is faulty there's no telling if the solenoid is opening or not during this time. But for safety you have to assume it is. Smell would probably be at the flue when it runs as oil is not escaping into your room. As for safety device to stop it happening - There isn't one.