HRM Wallstar Oil Boiler - Advice please

[SJB060685]

That capscrew is seriously tight, should the gasket be replaced when burner is split?

wish id paid more attention to what he was doing when he serviced it.
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I’ve contacted a 3 local heating engineers, 1 said he would go with pump bring issue. 1 said possibly pump but wouldn’t be sure and the other said it’s the control box.

When you split the burner any gaskets need to be replaced if not In good reusable condition. I've not experienced on this burner but have on a Riello where the seal had perished causing it to draw more air which was extinguishing the flame like you're experiencing at times.
I did not say for sure it was the pump, only suspicious and I based that on what I've seen heard and read, like I said I cant be sure without checking a couple things. Control box can cause this issue yes and the DKO does things slightly different in lockout mode but again it's hard to say without being there.

 

[Simonvr46]

As far as I’m aware the only parts that have been replaced during service are the filter and the nozzle, no mention of replacing gasket.

should that capscrew be stupidly tight to undo?

with regards to blast tube does that look in good condition?

 

[SJB060685]

Image from manual to show the long bolt you should be removing. Blast tube looked ok, usual wear and tear but overall in acceptable condition. Couldn’t see if there were any obstructions to the cell though

 

[Simonvr46]

View attachment 42435

Image from manual to show the long bolt you should be removing. Blast tube looked ok, usual wear and tear but overall in acceptable condition. Couldn’t see if there were any obstructions to the cell though

Found that image in the HRM handbook. Just didn’t know about how tight that screw should be? Used to screws and bolts having torque setting on them lol.

 

[SJB060685]

These things do quite often have torque settings yes. Alan key below on burner casing looks like the one going by image. Been a while for me on this burner lol

 

[Best]

The large Allen bolt is used for to split the burner (main part from part that also has blast tube and flange on it.
Removing the entire burner is fine if you make sure the seal at flange to boiler is still okay and the bolts are holding burner in firm.
No need to over tighten

 

[Simonvr46]

Found paper work from when it was last serviced, all the last few service record sheets I found all day pump pressure of 120psi even when it was serviced by a different company.

 

[SJB060685]

When was this last record dated? Smoke level fine, CO2 is about right depending on when it was serviced, excess air maybe a little too high. Pump pressure is looking good from my calculations.

 

[Simonvr46]

When was this last record dated? Smoke level fine, CO2 is about right depending on when it was serviced, excess air maybe a little too high. Pump pressure is looking good from my calculations.

That was July 2019 that it was serviced.
How is excess air reduced?

 

[Best]

Looks good readings to me, but I never just assume they are accurate or honest and do my own test results

 

[Best]

That was July 2019 that it was serviced.
How is excess air reduced?

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.

 

[SJB060685]

This needs to be done in conjunction with a FGA (flue gas analyser) and I shouldn’t tell you because randomly adjusting can through all other readings out. Ideally you want maximum combustion and CO2 with no excess air, this however is not practical in the modern world and you will always have a lower CO2 and certain amount of excess air, this is down to the fact increasing CO2 also increases smoke and soot emissions. Again CO2 is set depending on ambient air temperature and density. If excess air was too high it can force heat up through the flue and reduce efficiency, it can also cool the combustion process and increase CO ppm as well as extinguish flame, the data sheet suggests your efficiency and CO are good, certainly for a non condensing boiler.

 

[Simonvr46]

This needs to be done in conjunction with a FGA (flue gas analyser) and I shouldn’t tell you because randomly adjusting can through all other readings out. Ideally you want maximum combustion and CO2 with no excess air, this however is not practical in the modern world and you will always have a lower CO2 and certain amount of excess air, this is down to the fact increasing CO2 also increases smoke and soot emissions. Again CO2 is set depending on ambient air temperature and density. If excess air was too high it can force heat up through the flue and reduce efficiency, it can also cool the combustion process and increase CO ppm as well as extinguish flame, the data sheet suggests your efficiency and CO are good, certainly for a non condensing boiler.

Thanks for that, I’ve no intention of adjusting settings I’ll leave that to experts with correct equipment.
2 Questions

1 - Would the excess air cause the burner to lockout?
2 - Could excess be caused if that gasket hasn’t been replaced?

 

[SJB060685]

Like I said I have known flames to extinguish due to faulty gaskets/seals, however I would expect it to happen constantly if these were a problem.
If there was a problem with gaskets/seals causing an excess of air but not enough to extinguish flame then I would expect to see other readings on my FGA out and the sheet you showed me looked like very good figures (providing they are similar now). I did say the excess air was a bit high yes but only a little to what one usually would see.

 

[Simonvr46]

Like I said I have known flames to extinguish due to faulty gaskets/seals, however I would expect it to happen constantly if these were a problem.
If there was a problem with gaskets/seals causing an excess of air but not enough to extinguish flame then I would expect to see other readings on my FGA out and the sheet you showed me looked like very good figures (providing they are similar now). I did say the excess air was a bit high yes but only a little to what one usually would see.

Figures have been very similar on last few service record sheets, although the 1 from 2016 doesn’t show excess air.
Think I’ll give the electrode gap a check sometime this week.

 

[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.