Heatslave 12/18 ignition fire cycle

[R3su]

After a brief success with the boiler it’s thrown up another issue. During this cold snap the boiler fires up briefly, burns and then about about a minute it goes back to ignition stage. The cycle carries on; ignition, fire, ignition, fire… until I’ve had enough and shut it down.

Oil flow seems to be good so would it be the capacitor? Is there any way of testing it?

Thank you

 

[Johntheo5]

After a brief success with the boiler it’s thrown up another issue. During this cold snap the boiler fires up briefly, burns and then about about a minute it goes back to ignition stage. The cycle carries on; ignition, fire, ignition, fire… until I’ve had enough and shut it down.

Oil flow seems to be good so would it be the capacitor? Is there any way of testing it?

Thank you

Capacitors can be checked with a suitable multimeter but why not just install a new one, if the fan motor is starting up then unlikely that the capacitor will fail and cause the fan to stop anyway, if it runs ok for a minute or so then looks more like the fuel pressure, can you get a pressure gauge and comnnect it "permanently" to the oil pump pressure test port and just observe it, I've read your other posts re photo cell replacement etc so you have to start at the basics again. Unlikely but I've seen cases where a new photo cell is also faulty, its strange why the burner doesn't lock out.
Are you sure that Tiger Loop is OK, if the tank level is higher than the burner maybe replace the bypass plug if you still have it and blank the port to the tiger loop.

 

[oilhead]

Classic symptoms of blocked flue, or recirculation of flue gases.

 

[R3su]

Morning all.
Thank you for the responses. I have a new capacitor turning up Monday so will fit that. In the meantime I disconnected the air feed from the flue and let it draw from the room.
Fire, ignition cycle seems to have stopped which is a step forward.

The boiler still has my original issue of not firing when cold or between heating cycles. It tries but goes to lockout but will fire if I reset it within 2-5mins of lockout.

Oil pressure seems good and all filters are clear but will buy a pressure gauge so I can get a reading.

Hopefully a new capacitor will solve the lockout issue.

My partner has arranged for someone to price up a new boiler on Monday as well. So it’ll be interesting to see what they say. It was sooner than I really wanted to be replacing it as I wanted to look at hybrid boiler / ashp and tie that into a wood burning stove with back boiler.

Fingers crossed the for capacitor!

 

[Johntheo5]

Have you checked the flue as suggested, I think there is a flue manifold plate where you can look in, were the baffles cleaned recently?.

 

[muggles]

Definitely won't be the capacitor. If it was, the motor wouldn't run at all. Solenoid is more likely

 

[R3su]

Limped it along yesterday between other commitments but it’s back to the fire ignition cycle for a while before kicking in properly.
I’ll have to check flue manifold tonight after work. I thought the bypass had corrected it for the short term but I think it’s another problem.

Muggles, you mention the solenoid. There’s one connected to the pump Danfoss diamond. I had a new pump and decided to stick it on to rule out the old one but it made difference.

 

[R3su]

just a quick update.

Managed to get a number for a well recommended local engineer.

After a bit of head scratching he found the burner gasket was missing and the condensate trap was full of debris (probably from when it was over fuelling a year or so ago).

He tightened the burner up (I’ll get a new gasket) and cleared the trap and it seems to be burning nicely now.

It’s back on schedule now so proof will be when it tries to start from cold.

Fingers crossed!