HRM Wallstar Oil Boiler - Advice please

[SJB060685]

Above is a screen shot of what the electrode dimensions should be. Also note the burner head dimensions of 3-5mm. Like I said I haven’t touched a sterling burner in some time so would have to re familiarise myself. The Alan key you were turning under black cover might be the adjuster for nozzle assembly position, again I can’t remember off the top of my head so apologise if it’s not. Both are extremely important to ensure safe and non delayed ignition.
Check those out if you feel compelled but the rest leave to the engineer, I know you have a background in engineering and more importantly that you know your limits. The attending engineer should take the time to check everything.

 

[Simonvr46]

View attachment 42437

Above is a screen shot of what the electrode dimensions should be. Also note the burner head dimensions of 3-5mm. Like I said I haven’t touched a sterling burner in some time so would have to re familiarise myself. The Alan key you were turning under black cover might be the adjuster for nozzle assembly position, again I can’t remember off the top of my head so apologise if it’s not. Both are extremely important to ensure safe and non delayed ignition.
Check those out if you feel compelled but the rest leave to the engineer, I know you have a background in engineering and more importantly that you know your limits. The attending engineer should take the time to check everything.

Cheers mate, much appreciated with your help and guidance. Best hunt out my feelers to check gap. Must remember to disconnect boiler from power supply, don’t want boiler starting up while I’m checking electrodes lol.

 

[SJB060685]

Cheers mate, much appreciated with your help and guidance. Best hunt out my feelers to check gap. Must remember to disconnect boiler from power supply, don’t want boiler starting up while I’m checking electrodes lol.

Yes isolate power to system at switched fused spur and shut oil off, take solenoid off as well if really worried. Didn’t say this because it’s obvious lol.
Like I said whoever attends needs to check everything from start to finish, explain to the engineer that sometimes it starts and you lose flame during safety time then lock out and other times it won’t even start, tell them what parts have already been replaced randomly (which is not a sign of a good engineer) and hopefully they’ll get to the bottom of it. From the video I took pre purge, ignition, then loss of flame, cell senses that, I heard the solenoid close and then thermomechanical switch cause lockout. However that doesn’t explain why sometimes it won’t even start, so couple issues might be found.

 

[Simonvr46]

Yes isolate power to system at switched fused spur and shut oil off, take solenoid off as well if really worried. Didn’t say this because it’s obvious lol.
Like I said whoever attends needs to check everything from start to finish, explain to the engineer that sometimes it starts and you lose flame during safety time then lock out and other times it won’t even start, tell them what parts have already been replaced randomly (which is not a sign of a good engineer) and hopefully they’ll get to the bottom of it. From the video I took pre purge, ignition, then loss of flame, cell senses that, I heard the solenoid close and then thermomechanical switch cause lockout. However that doesn’t explain why sometimes it won’t even start, so couple issues might be found.

Who ever I get to come look at boiler I’ll be keeping closer eye on, I think after chatting to you guys on here with the advice you have all given me I think I have a decent understanding on how it all works and what to look for.
I’ll have look at electrodes 1st then get someone to look at it.

 

[Simonvr46]

Adjusting the air is for your oil service person to do using an analyser.
I would say excess air is fine. The CO2 reading is good and reducing the air will begin to increase the CO2.
You tried putting your hand partly over air intake and it didn’t help, so leave air settings untouched.

Hiya,
Ive no intention of adjusting any settings as although the burner is pain in backside sometimes, the majority of time it’s ok so I’d rather it be like that until it’s sorted out properly.
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View attachment 42437

Above is a screen shot of what the electrode dimensions should be. Also note the burner head dimensions of 3-5mm. Like I said I haven’t touched a sterling burner in some time so would have to re familiarise myself. The Alan key you were turning under black cover might be the adjuster for nozzle assembly position, again I can’t remember off the top of my head so apologise if it’s not. Both are extremely important to ensure safe and non delayed ignition.
Check those out if you feel compelled but the rest leave to the engineer, I know you have a background in engineering and more importantly that you know your limits. The attending engineer should take the time to check everything.

I had chance today when I got home from work to check electrodes. I unhooked burner unit like I had the other day and got my trusty set of feelers out. The electrodes appear to be within the specified tolerance of the the screenshot page.
I did take blast tube off and give the fins at the nozzle end a good clean, I’m assuming the fin that has corner bent over is for the photocell to detect flame? I made sure it was clean.
Also had quick look at the pump, took cover off and then undid the 3 Allen head screws, pump gears looked clean, couldn’t see anything obvious. Without fully stripping pump down and measuring components it’s hard to tell if parts are worn. Once bled air out of pump it started up 1st time.
I’ve been quoted about £125 + vat to have new pump fitted.

 

[SJB060685]

Yes there should be no obstruction so the cell can detect light, if there was the burner would ignite then go to lock out due to no flame sensing.
I mentioned the pump gear set, drive key and coupling but did not say have a look yourself lol. I know you have a back ground in engineering but I only ever opened up a pump if I had spare seals and pump at hand and after I was confident there was a problem with it. What was the drive key and pump coupling like? These pumps should all be put back together with a certain torque as we discussed above.

 

[Simonvr46]

Combustion is most likely then poor if flame isn’t partly being obscured from photocell view.
But can have one of many causes.
Nozzle could be faulty, or air setting wrong or burner drawing in flue gases, or oil pump pressure is set wrong, are some possibilities.

Current heating engineer has replaced nozzle at every service.

Pump pressure recored at the last service in 2019 was same as service in 2016 by different company and is correct to what the specification of burner

How would the burner draw in flue gases? Wouldn’t that be picked up on flue gas analysis?

If air setting was wrong wouldn’t that affect co and flue temp etc?
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Yes there should be no obstruction so the cell can detect light, if there was the burner would ignite then go to lock out due to no flame sensing.
I mentioned the pump gear set, drive key and coupling but did not say have a look yourself lol. I know you have a back ground in engineering but I only ever opened up a pump if I had spare seals and pump at hand and after I was confident there was a problem with it. What was the drive key and pump coupling like? These pumps should all be put back together with a certain torque as we discussed above.

From what I could see and feel, there was a bit of play in the gear wheel against the drive key but without knowing what is acceptable it’s hard to judge.

Had the seal on the external case needed replacing I have numerous o rings and could have temp fixed. The main body of pump is metal on metal so gave it a clean prior to reassembly.

I found data sheet for the Danfoss BFP11 pump and no torque settings shown on it, so a gentle nip or as we call it a British Standard Nip.

 

[SJB060685]

I cant remember the correct torque setting, I'm sure I saw it on a danfoss bfp pump YouTube video.
The drive key should be solid in its groove with no play, if there was it could cause your issue and eventually shear completely and you would have no pressure or ignition. A photo would of been nice but I'm not suggesting open up again. A dodgy pump coupling could also cause the same.

The burner could draw in flue gases if the flue seals had failed or burner flange gasket was faulty, or anywhere else that could allow products of combustion to escape inside the casing. You could detect these products with a FGA yes.

Just out of curiosity have you ever dipped the tank for traces of water with detection paste? I'm sure this isn't the problem due to what I've seen but thought I'd ask.

With regards to the quote for changing the pump I'm not so sure if that will help now based on what you've said today but without seeing the gear set, drive key or coupling I cant say for sure.

 

[Simonvr46]

I cant remember the correct torque setting, I'm sure I saw it on a danfoss bfp pump YouTube video.
The drive key should be solid in its groove with no play, if there was it could cause your issue and eventually shear completely and you would have no pressure or ignition. A photo would of been nice but I'm not suggesting open up again. A dodgy pump coupling could also cause the same.

The burner could draw in flue gases if the flue seals had failed or burner flange gasket was faulty, or anywhere else that could allow products of combustion to escape inside the casing. You could detect these products with a FGA yes.

Just out of curiosity have you ever dipped the tank for traces of water with detection paste? I'm sure this isn't the problem due to what I've seen but thought I'd ask.

With regards to the quote for changing the pump I'm not so sure if that will help now based on what you've said today but without seeing the gear set, drive key or coupling I cant say for sure.

I would have hoped current heating engineering would recognise fault if flue gases was being drawn back in.

I’ll have another look at the pump sometime this week and take photo. Im not sure if it was the shaft rotating of if it was the gear wheel on the drive key/ drive key in shaft.
I know when we had new oil tank in 2017 there was no mention of water in the oil when the existing oil was pumped out, also the pump showed no signs of water being sucked through.

 

[SJB060685]

If there was emulsified oil you would have seen a white gooey paste like substance. I was almost certain this wasnt the case but thought I'd ask.