Bentone B11 burner always locking out.

[Best]

Anyone any ideas? Never had bad luck like this!
At a boiler with a Bentone B11 burner that would constantly lock out after about 2hours on.
Firstly, this burner is only 3 year old & in brand new condition to look at. I have checked nearly everything including the oil getting to burner, the strength of spark, etc etc & all excellent. It is not the control box or the photocell or the solenoid or the capacitor! Burner runs lovely. I am thinking the solenoid valve is perhaps faulty but haven't had any bother before.
Any ideas would be appreciated, thanks!

 

[Best]

Have you been there when it locks out? Is it during startup or while it's running?

No, AtlasGas, I prefer to see it going to lockout, but I would have to waste a couple hours sitting outside in the cold. It constantly will run off & on for about 2 hours until lockout.

 

[Best]

Thanks to you both for the advice! I will go back tomorrow & replace the transformer & test the oil line while I am there. Normally I sort the fault first go. This has to be a record - that will be the 5th time I will call & still counting! :smile:
Will report back.

 

[Killy Bing]

Coil breaking down? Abit soon. Butt if you have a spare swap it out, if it runs without locking out then leave it on, if not swap the old one back

 

[Best]

Coil breaking down? Abit soon. Butt if you have a spare swap it out, if it runs without locking out then leave it on, if not swap the old one back

No, not the coil, - I replaced it first & boiler still had same problem. I carry new Danfoss solenoids always. The faulty Danfoss solenoids I find either die totally or last from cold up to a maximum of one hour on continuously. I replaced the coil on test really & when that didn't cure it, I thought it had to be the box. Just hope I haven't got a faulty brand new part!

 

[Killy Bing]

Intermittent faults, satisfying to solve but a pain in the backside

 

[WHPES]

Have you checked the fuel supply / oil tank for presence of water? Have had that causing lockouts after an hour or so in the past.

Check fuel filters including the one on the fuel pump.

 

[Best]

Have you checked the fuel supply / oil tank for presence of water? Have had that causing lockouts after an hour or so in the past.

Check fuel filters including the one on the fuel pump.

I normally do check the tank & filter for dirt/water, but for various reasons I thought that unlikely - the old nozzle & assembly was spotless, oil filter is 3 year old, oil tank is a type that rain water cannot enter & I ran the oil into a container from the oil hose & flow was great & oil clean.
But I know I need to check that out properly & will also do that tomorrow.

 

[Soggy]

Do you know at what stage is locks out? Does the motor spin up before the lockout but no ignition?

I have had a few like this that turned out to be the pump. Seems that if it stopped in a particular place, it stalled the motor but would then restart.

 

[kimbo]

I had a similar one with a sterling burner, as previously said I would have gone for the transformer. After the 3rd visit it turned out to be a ht lead partially blocking the photocell. Could have kicked myself for not checking first time

 

[Best]

Do you know at what stage is locks out? Does the motor spin up before the lockout but no ignition?

I have had a few like this that turned out to be the pump. Seems that if it stopped in a particular place, it stalled the motor but would then restart.

No idea what stage it goes to lockout. It one of those problems that only occurs it seems after it has been running for probably 2 hours. A tight spot on oil pump or motor bearings - I watch out for, but nothing seems wrong with them & the entire burner would easily pass as brand new!

 

[Best]

I had a similar one with a sterling burner, as previously said I would have gone for the transformer. After the 3rd visit it turned out to be a ht lead partially blocking the photocell. Could have kicked myself for not checking first time

I thought on the ht leads & checked them when I examined the electrodes for cracks. The ht leads are a bit long but are folded away from photocell. In fact, I checked & thought just about everything. The boiler hadn't been touched & suddenly started this locking out. Nothing I have done has made any difference. I am happy to replace the transformer to test, but old one seems fine. I have been wondering if something is wrong with oil pump or it's stem, but this burner is only 3 years old & mechanically would normally be very reliable as you know.

 

[Soggy]

Unfortunately, with this type of problem, you may have to diagnose by trial and error. Keep swapping things until you find it.

At least it locks out every two hours, so you should be able to fix it quickly, not so easy when the intermittent fault only occurs every week or two.

 

[Dotty]

Short of air being pulled in I'd also be looking at the pump and the integrity of the pipework.

Another good one that caught me out once is debris in the tank that's too big to go down the outlet.

 

[snowhead]

Couldn't you get the customer to ring you when they've reset it and then you arrive 1+1/2hrs later.

You'd only be in the cold for 1/2 hr or less.

 

[bright spark]

Had a problem like this in the past with one of these. Talked to bentones man in Ireland. He said to change the motor. Did it and it worked for me. It was a similar situation to yours.