Heatslave 26/32 Burner/air issue

[john975]

That's another half hour running, dropped the boiler thermostat down and it started up as it should when temp dropped. ill let the boiler cool down/turn it off and see what happens.

 

[Agile]

If a CS photocell my recollection is that they are not very stable in their temperature related resistance either.

But they were around in the days of electronic valves before semiconductors.

Tony

 

[Burnerman]

This is a sign of too much air entering the burner.....as per Oilheads post earlier on.
Effectively, its blowing the flame out, especially when the boiler is cold.
John

 

[john975]

This is a sign of too much air entering the burner.....as per Oilheads post earlier on.
Effectively, its blowing the flame out, especially when the boiler is cold.
John

But surely when plumber adjusts air/combustion he would know this?

Are you saying the Air screw needs turned down???

if that's the case i assume the flame is not burning as hot/consistently and the photocell is not sensing the flame?

 

[john975]

he has turned the air screw down. ...fired up straight away. Was at 15 unsure what he turned it down too.

There is still an issue, said he would have another look after xmas.

Could not put the silver box on as it just choked.

 

[Burnerman]

Without a flue gas analyser, all is guesswork....does he have such a thing?
Just a point - if a new oil pump has been fitted, they are often set very high at the factory, maybe 150 psi, which is usually much too high. This could be the reason for the air door being well open at 15. If I remember, 9 or 10 is usually about right but that's a guess!
John

 

[Burnerman]

If your burner is overfiring, the flame is too far ahead of the nozzle.....maybe that's what's confusing the photocell?
John

 

[john975]

Without a flue gas analyser, all is guesswork....does he have such a thing?
Just a point - if a new oil pump has been fitted, they are often set very high at the factory, maybe 150 psi, which is usually much too high. This could be the reason for the air door being well open at 15. If I remember, 9 or 10 is usually about right but that's a guess!
John

yes he has the kit. he measured pump pressure and used gas analyser last time he was here(when new pump was put on). he never re-tested after he turned the screw down this visit.

there is no black smoke and does not stink lol

 

[john975]

If your burner is overfiring, the flame is too far ahead of the nozzle.....maybe that's what's confusing the photocell?
John

That makes sense to me. But i don't understand how plumber did not figure it out. lol

 

[Burnerman]

That makes two of us...but altering the air incoming volume has to affect the C02 percentage in the exhaust gas. There's a chance, if there is a flue problem, the gas analysis readings are corrupt.
Sorry I haven't any data on that boiler at present, (not at home) so I can't advise on what the oil pressure and C02 should be.
John

 

[oilhead]

If the burner improved when covering up the air intake, then this suggests over aired combustion with flame detachment. The photocell would be obstructed by the diffuser in this case, as confirmed by the retention of flame when the photocell was lit by a torch.
The fact that it does not work with the burner box on is probably a totally different problem. Sort out the burner first, then address the flue problems.
How many 'engineers' have you had to this? You seem to be particularly unlucky, or are you making do with a cheapskate?

 

[john975]

Well seems to be working for the moment , i will come back with the full story once its fixed properly.

Thanks to All for the input.

If the burner improved when covering up the air intake, then this suggests over aired combustion with flame detachment. The photocell would be obstructed by the diffuser in this case, as confirmed by the retention of flame when the photocell was lit by a torch.
The fact that it does not work with the burner box on is probably a totally different problem. Sort out the burner first, then address the flue problems.
How many 'engineers' have you had to this? You seem to be particularly unlucky, or are you making do with a cheapskate?

I have stuck with this guy because he done the service and was supposed to do the repair. I have only had one engineer to it. the burner has now been working most of the day with the box off. And the air screw set at 10. however he never checked c02/temp after altering the air intake. I do not have the kit to double check this myself or pump pressure. 15 is the approx. air setting for 32kw (rs)according to the installation manual.

And I don't expect him to be cheap, chances are I will have to pay for the parts that were not needed. Also will probably be billed for extra time it has taken him to figure out the problem. I also expect to have to hassle him to come back after xmas to sort the boiler properly. There is no such thing as a cheap heating engineer either way you pay lol

 

[gigz]

Did he leave details of the oil pressure setting ?

 

[john975]

Did he leave details of the oil pressure setting ?

nope but he had a pressure dial thingy on the pump on previous visit.

according to the installation manual, if he has tried to set it for 32kw it should be approx. 130 psi and 15 air setting for RS

But again I cannot verify that.

its a sterling 40 burner

 

[john975]

maybe he has set the psi at 110 psi for 28.5kw thus air setting off 15 was too far out?

I assume that would make sense in theory lol