danesmoor 20/25 burner lockout

[alexmurchison]

aimed at any worcester installers or someone in the know, this is the situation. was called to a boiler as it was in lockout mode and would not restart. he said it was due a service, so went through all serviceable parts and gave it a good clean, after the service when i needed to fire it up it wouldnt reset, so started checking componants . took burner out and pressed reset. motor ran, lots of spark but no oil, so repllaced coil and still no joy, worcester said control box fault so went back and replaced with a new unit. still no joy !! after a quick test on the multimeter they said it was a photocell fault, so replaced unit inc leads to box. still nothing, no oil from pump (no live to coil) by this time worcester wanted to send one of their own out and charge the customer a fee for the privelidge. After disconnecting all wires from control box then putting them all back it for some reason started up and then ran fine, apart from a grind from the pump, so replaced with new oil pump inc new coil, fired up, so analyzed it left it running all seemed well, day later it locked out again !!! with worcester not having a clue, it just seems like one of them jobs where there is no clear fault !!

Total new parts include oil pump (bfp 11 L3) / new coil / new tf830 control box / new mz photocell and leads

During service the was plenty of oil, it held its pressure so clearly not a fuel problem, but with the previous fault of no power to coil, it has to be something electrical !!! but as always it works while im there then locks out when iv gone, and as always the customer frowns their eyebrows at the number of return visits needed and the increasing cost !! anyone had a similar fault and what was the cause please.


Not related but last week had another danesmoor with similar fault, new coil / photocell / non return in oil line / control box etc, even though there was sparks produced from transformer, my last visit just replaced it anyway, and its ran fine ever since !!! now there is a beuty of a spark produced on the above boiler but even still, this wouldnt stop the coil from been energized ??

 

[SimonG]

Had a heatslave with exactly the same, it was the transformer.

 

[Best]

If you are certain the coil had no power to it, (when it should have) then you might have a faulty new control box. Check all wires to box & that the coil is plugged in fully. Only other thing is photocell.
Ignition leads shorting & weak motor capacitors are other intermittent faults I find.
You may as well have put a brand new burner in! :smile:

 

[SimonG]

So you've left all those new parts on and charged?

 

[Best]

Had a heatslave with exactly the same, it was the transformer.

That's what I was thinking, - he was misreading the coil faulty, when it was something totally different. A nice spark from the electrodes, doesn't mean the ignition leads or transformer are fine.

 

[Dotty]

Had the same problem with a sterling a while back. T'was the transformer then too.

 

[alexmurchison]

thanks for all the replies folks, i suppose wil have to try a new transformer, only downer is its not one of the regular danfoss EBI units its one of the older types, so will have to order it.

As with charging for all parts, Pump WAS required anyway which has a new coil fitted and is in with the pump price, photocel was sooted up and giving readings indicating false light, not an expensive part anyway, but needed the £2 leads as come in 2 parts anyway. control box however can be taken off and refunded against new transformer if its that at fault !

I shall get a new transformer then update in a day or 2 if problem clears or persists, thanks guys.

 

[Best]

I normally say just about any burner can be fixed, but if you are charging properly, then fitting a new transformer + cell + oil pump as well as other parts like oil hose & nozzle is not worth it. Burner is a write off. A new Sterling burner would be best.
Those older Danfoss transformers must be expensive.

 

[alexmurchison]

Hi thanks Best,
just been back this morning for a another look. removed burner and on first sight there was fluff or something lodged between blast tube and nozzle. (surely cant be that easy) removed it, obviously come in through fan housing. Reset but nothing, cupped the photocell in my hand and tried agian and presto it lit !!!! but for some reason when its back insitu it wouldnt lite ( reason for not sending live feed to coil ) checked the whole burner for possibilities of light getting in. In a dark place shon torch in, and two clear signs of light getting in, where high voltage cable enter burner to electrodes the holes are probably a 12mm diameter, but by loosening the transformer and pushing further back, the insulation from the transformer actually cover the holes. Fastened it all back up and it struck up first time, so i sat there for half hour, letting it click off on temp then back on, and me turning it on and off. Worked every time...... hopefully the end of the saga, but yes i agree there is a limit i would offer to spend on it before recommending a new burner ,

 

[Best]

Hope that's you sorted. Interesting if that's the cause.
Saw a similar problem on a burner that wouldn't burn when insitu, & it was a badly installed oil hose that kinked when burner fitted. Just needed new hose.

 

[alexmurchison]

didnt last, called me today to say locked out again. worcester said could be a "dry wire" basically one of the supply leads damaged and after a while cutting it out ?? longshot but to eliminate this tried replacement lead from control box to coil, to photocell, to transformer and to motor.....still no improvement. so swapped all back after doing a continuity test on all of the leads. again it would only light with the burner out and the photocell cupped. Once it has worked once it works every time once i put the burner back in situ.... now im not sure if the photocell is picking up on false light caused by the sparks at the electrodes, as it will not light with the f/c aimed at the nozzle so to speak, tried turning it 90 degrees facing down, and seems to work, so can still pick up light and dark signals, but not aimed directly at sparks. will see if get called back tommorow ????? told him im at a loss if it does it again as physically have tried all parts been replaced, bar motor itself ! maybe a new burner if this fails ?

 

[Dotty]

As has been stated before. Sometimes you can throw everything at a burner and it still not go. It's question of cost and time spent. Sometimes you have to be honest with yourself and your custard and admit defeat.

Having said that I had a riello giving all the symptoms of a photocell problem. After three new photocells and a replacement control box I found I had a dodgy oil pump.

I just charged my custard for the pump and time.

Over time I've collected a selection of parts that I use for diagnostics and emergency repairs.

 

[Best]

That's puzzling!
Holding your hand over the photocell should mean the electrodes keep sparking, then you say the burner will work after that initial fire up? This, to me indicates that the oil to air mix is way wrong - especially if there is too much air. Classic sign is what you are doing with the photocell. Either you have a faulty nozzle or you need to use smoke pump + analyser to set air. Oil pump pressure on Kerosine will need to be 100psi or more.

 

[SimonG]

Never thought to ask what the oil pressure and CO2 was like.

 

[Best]

Never thought to ask what the oil pressure and CO2 was like.

I should have asked that earlier also.
It really does sound like it is just struggling to ignite & when the photocell is blacked out, ignition keeps running & the burner gets a chance to fire up, & then because of the heat it will continue to fire each time. Next cold start it won't.
Maybe just a set up needed. A visual of the flame is handy, though, a bit of a safety issue.

 

[Dotty]

I just reread the original post and he did say he replaced the pump and checked the pressure. Assuming he is getting a constant 8bar then it could be an air/oil mix. that's 3 of us didn't ask about combustion readings!

Whereabouts in NI Bestie?

 

[Best]

Whereabouts in NI Bestie?

Beautiful County Antrim, Croppie! North Belfast.
Those Riello oil pumps, you mentioned are a pain. Always assume they might be at fault. Have a wee careful look at the gears in them if you suspect them. Usually find the drive torn into the first gear & possibly twisted, causing the odd lock out.

 

[alexmurchison]

hi all, yes it did have a new pump fitted, the problem occured before and after new pump was fitted, off the top off my head the pressure was 110psi, and helf fine. I set co to around 11.5. now you mention it (never crossed my mind) but i did have to wind the air damper way open to get to this setting, hmm, maybe need to go and have a second look at this, I have only just got my analyzer back from testo after complaining it was giving false readings !! this sound very convincing, struggling to start from cold ??? although woouldnt it still purge and spray oil out ?? when i have had burner out (boiler in garage ) and ran it, not even a dribble comes out , always after a fiddle with the F/C it seems to work

 

[Best]

Use a smoke pump to get the air setting about right.
Hope I am not stating the obvious, but quick way is to set the air to a lowish setting first, where it probably has a smoke number about 1, then raise air very slightly till you get it at 0. That might be a little bit too fine a setting, but will do to fire & test the burner.
If you used the correct nozzle & the nozzle assembly & electrodes are not moved from proper position, then it should fire.

 

[alexmurchison]

think i finally got to the bottom of this issue. locked out again, and so scratching my head was sure of my next step, luckily ran into another (very time served) oil fitter in supppliers and suggested disconnecting flexi from internal tap and dipping it in a tub of oil and see if fired , certainly did first tiome and stayed working, so proved a fuel shortage in the oil line, (strange seen as oil pressure held after fitted new pump ?) but anyway removed filter at tank end and blew back from boiler, the amount of black crap and particles that came back through and collected in a jug was unreal, even though i cleaned the filter out, so much dirt had bypassed it and just sat in the fuel line, must of affected the flame in some way causing photocell to react and lock it out, blew it through both ways till perfectly clean oil came through then reconnected !! its ran perfect since, touch wood !!

 

[SimonG]

Nice one.

 

[Best]

Glad you got it sorted. The oil lines need a good flush & helps to fit paper element filter at tank.