HRM Wallstar Oil Boiler - Advice please

[Sausage_Hider]

Hi all,


I have a Wallstar Oil Boiler 12/15.

A few years ago, it developed a problem where it would fail and it required a manual reset on the boiler controller outside.

I didn't know much about oil boilers back then.

I have had a number of 'heating engineers' and so-called specialists to it but so far none have cured the problem.

I decided to figure out how these things work for myself to give me a greater understanding of what is going wrong.

So, this is what happens.

When there is demand for heat, the boiler from cold (in a none failed condition) fires up without the slightest problem.

It runs to get the water hot, shuts off, starts again as water cools etc... normal running.

Then, for no apparent reason, say after 30 mins or 1-hour etc, it will fail to ignite. This triggers the fail and requires a reset on the controller.

Sometimes the reset will work and the boiler will fire up and continue, sometimes it will just keep failing.

If I leave it to cool down for a few hours, it will generally fire up as normal (after clearing the fail with the reset).

It seems that when the boiler is very cold, there is no problem. If it is also very hot, it doesn't seem to be a problem, but in-between is where it fails.

The engineers etc have changed the nozzle, plastic pipe, solenoid, controller and filters and the problem persists.

Now then, things I have checked.

When starting, the pump runs (pulsing of the oil can be seen in the clear pipe). It does its 10-15 second purge then the solenoid clicks and the oil flows, boiler lights.

All good.

When it fails, it NEVER fails when running, only on re-starting during the normal heating cycle.

It goes through the normal procedure as above, solenoid clicks open, oil is seen to flow and then within about 3 seconds it shuts off with the fault.

Now, as I can see the oil moving, it isn't the solenoid, it’s not air as I can see the oil in the line, it’s not a blockage as again I can see the oil moving in the line.

It seems to be the igniter.

I have had it apart, cleaned the electrodes, checked the gap 3mm+-0.5mm and level with the top of the nozzle.

It's not the flame detector because when it fires up, you can hear it ignite and it doesn't get that far.

Does anyone have any experience with this same fault and how was it cured?

Could it be the transformer (that creates the spark), the leads to the electrodes or the electrodes themselves.

Puzzling as it only fails when the boiler has been running. The temperature in the burner cabinet is always quite cool, but the fault is definitely heat related!

This must be a known problem, on my street 12 houses, we all have the same boiler and 7 of them have the exact same problem.

Surely someone must know what the problem is.

Oh, the boiler is about 12 years old.

Thanks.

Martin

 

[Best]

Just get a genuine oil service person who has experience in oil burners and some fault diagnosis skills.
That fault as you describe can be narrowed down immediately to a likely cause.
Although tbh, I can think of 3 parts that can cause failure on the timing you mention.
Note that when the system is up to full heat, the oil burner will run less and some parts will be less likely to fail due to heat up causes.

Also, - Just because a part works properly a few times does not mean it is not failing intermittently.

 

[Sausage_Hider]

Thanks for your reply.

What 3 parts do you think please?

Out of all of us on the street with the same problem we have been through many an engineer.

Now 3 of us have had remote resets fitted so we can re-set the boilers without going outside because no one seems to be able to do anything.

These boilers are not exactly complex which is why it is so annoying that the fault cannot be found.

It is definitely an intermittent fault.

I have 3 ideas at the moment.

1. A crack in the porcelain insulators on the electrodes which is allowing tracking of the ignition spark when it is hot.

2. The short rubber coated HT leads from the transformer to the electrodes. Maybe breaking down with heat.

3. The transformer itself.

As the transformer is on the outside case of the burner, it doesn't get hot, where as the other two are inside the burner itself and subject to heat.

What do you think?

Thanks

Martin

 

[Best]

Electrodes and leads are usually easy to visually rule out.
I have only your description to go by and frankly your service people should have solved it.
Seems strange that 7 out of 12 have the same problem.
I really cannot give advice on open forum of how to tamper with an oil boiler, although I am tempted.
@SimonG is also an oil guy on here, but I think he will say same.
If the fault is so frequent, why has all the service people not replaced a probable faulty part?

 

[SimonG]

With Best on this.

 

[SimonG]

Whereabouts in the country are you?

 

[Theboilerman]

Ebi transformer.
Danfoss say they don't have intermittent faults but I've had a few that have started playing up.
I'd change that if the leads and electrodes look ok.

 

[Simonvr46]

Hi, we have a Wallstar 15/20 boiler which has intermittent lockout.

Having had heating engineer to it numerous times and have had firevalve/NRV, clear hose, ebi transformer replaced it ran all through the summer using only for heating water.

Boiler now being used for HW and CH it’s on for longer and has intermittent lockout.
I’ve replaced photocell and solenoid myself and still no joy.

The clear hose has a air bubble which I ceased to a decent size but seems to get to max size then stays at that size with oil either side of bubble.

heating engineer believes it’s this air bubble that’s causing issue, yet when air is removed from clear hose in the evening the boiler locked out the next day so I’m not convinced it is the air that’s issue. Was suggested by him that a tiger loop would solve problem, again im not convinced.

I’ve no problems with spending money on the boiler to get it fixed but don’t want to waste money on replacing parts or adding parts if it ain’t going to fix it.

after reading several over forums I decided to try the capacitor. Found a local company and got new one for £6, wasn’t sure how to remove the existing one so I’ve temporarily cable tied the new one to the existing on for time being. The old capacitor had brown residue around the base of the terminals.

I hope that this resolved my issue.......

Anyone got any suggestions on removing capacitor and also on how they have sorted boiler out?

 

[SJB060685]

Theres a reply to this but I cant see it again? I know this thread is old but would be keen to know if the OP has a result. From what I've read this sounds as if it's an ignition problem which is what you guys have suggested above.

 

[SimonG]

Aye reply just after 8 this morning.

 

[SJB060685]

Hi, we have a Wallstar 15/20 boiler which has intermittent lockout.

Having had heating engineer to it numerous times and have had firevalve/NRV, clear hose, ebi transformer replaced it ran all through the summer using only for heating water.

Boiler now being used for HW and CH it’s on for longer and has intermittent lockout.
I’ve replaced photocell and solenoid myself and still no joy.

The clear hose has a air bubble which I ceased to a decent size but seems to get to max size then stays at that size with oil either side of bubble.

heating engineer believes it’s this air bubble that’s causing issue, yet when air is removed from clear hose in the evening the boiler locked out the next day so I’m not convinced it is the air that’s issue. Was suggested by him that a tiger loop would solve problem, again im not convinced.

I’ve no problems with spending money on the boiler to get it fixed but don’t want to waste money on replacing parts or adding parts if it ain’t going to fix it.

after reading several over forums I decided to try the capacitor. Found a local company and got new one for £6, wasn’t sure how to remove the existing one so I’ve temporarily cable tied the new one to the existing on for time being. The old capacitor had brown residue around the base of the terminals.

I hope that this resolved my issue...

Anyone got any suggestions on removing capacitor and also on how they have sorted boiler out?

Hi. Your comment has only just become visible to me!
If you have a multimetre capable of reading capacitance then you could test old capacitor to see what its value it has, I suspect however if you're saying its showing sign of dielectric leakage then it might very well be the culprit, although I'm not saying for sure it is or that there isn't other faults, time will tell.
With regards to the air bubble are you sure you're not drawing air in? These Wallstar boilers are obviously designed to be mounted on an external wall and able to draw oil up a maximum of 2 to 2.5 metres if I remember correctly. This means the oil will be sucked up and under negative pressure for part of the supply line, also if this negative pressure was too low gases can separate in the oil causing these problems. However if this has been fine for sometime before the problem then I doubt the install is wrong.
A tigerloop will lift, deaerate and preheat the fuel but many of these boilers work fine without one providing installed correctly and don't exceed suction capacity of the pump, so unless you have a constant air ingress problem then you shouldn't need one.
If it was just the capacitor then I expect you to not have experienced another lockout in the time between your comment and my reply now.

 

[SimonG]

The wallstars always have an air bubble in the clear oil hose. Never seen one without it.

Capacitor would make sense.

 

[Simonvr46]

Hi. Your comment has only just become visible to me!
If you have a multimetre capable of reading capacitance then you could test old capacitor to see what its value it has, I suspect however if you're saying its showing sign of dielectric leakage then it might very well be the culprit, although I'm not saying for sure it is or that there isn't other faults, time will tell.
With regards to the air bubble are you sure you're not drawing air in? These Wallstar boilers are obviously designed to be mounted on an external wall and able to draw oil up a maximum of 2 to 2.5 metres if I remember correctly. This means the oil will be sucked up and under negative pressure for part of the supply line, also if this negative pressure was too low gases can separate in the oil causing these problems. However if this has been fine for sometime before the problem then I doubt the install is wrong.
A tigerloop will lift, deaerate and preheat the fuel but many of these boilers work fine without one providing installed correctly and don't exceed suction capacity of the pump, so unless you have a constant air ingress problem then you shouldn't need one.
If it was just the capacitor then I expect you to not have experienced another lockout in the time between your comment and my reply now.
[//sjb060685

Hi SJB060685 thanks for your reply, took awhile to show on here as it said had to be approved.

I forgot to add to my post that we had a new oil tank installed back in 2017, the oil tank was moved to new position. We had this issue prior to the new oil tank.

Since fitting new capacitor the boiler has worked without issue but as it is intermittent the boiler sometimes goes a week without lockout so not counting my chickens at the moment.

The pump on the boiler is less than 2 meters above the outlet on oil tank.
I did read on another forum about gases causing the bubble.
I’m not sure if our heating engineer has checked pump pressure.
Heating engineer has checked all of the oil line connections.

Any idea how the old capacitor is removed?

 

[Simonvr46]

The wallstars always have an air bubble in the clear oil hose. Never seen one without it.

Capacitor would make sense.

HRM tell me that as long as it’s static and not a constant stream of bubbles it’s ok, the guy I spoke to said they have 2 boilers in workshop, 1 has no air bubble and the other has 10inch air bubble.

 

[SJB060685]

Hi Simonvr46. Your post has only just become visible now at 8.20pm Monday.
Honestly I have little experience with these boilers, in fact I've installed and worked on one a long time ago lol, so without seeing the burner and how the capacitor is mounted I couldn't tell you, some are screwed in and others are done differently.
When a capacitor is faulty it can still charge to and discharge charge and cause intermittent faults like you experienced but eventually it will stall the motor, fuel is not pressurised and no ignition.
I suspect changing the capacitor has cured your fault but like you say time will tell.

 

[Simonvr46]

Hi Simonvr46. Your post has only just become visible now at 8.20pm Monday.
Honestly I have little experience with these boilers, in fact I've installed and worked on one a long time ago lol, so without seeing the burner and how the capacitor is mounted I couldn't tell you, some are screwed in and others are done differently.
When a capacitor is faulty it can still charge to and discharge charge and cause intermittent faults like you experienced but eventually it will stall the motor, fuel is not pressurised and no ignition.
I suspect changing the capacitor has cured your fault but like you say time will tell.

Some reason all my posts take awhile to come online as they have to be approved.......

So far so good, every time we’ve had a demand on the boiler for it to start it has done, hopefully in couple of weeks time I’ll still be smiling and saying the same comment.
If it does solve the issue I’ll be looking for another heating engineering to service boiler in future.....

 

[SJB060685]

A capacitor is basic knowledge and always one of the first things to consider/check when experiencing your issue.

 

[Simonvr46]

A capacitor is basic knowledge and always one of the first things to consider/check when experiencing your issue.

I work in mechanical engineering and have a basic understanding of electrics, hence reason off checking/replacing capacitor also that it’s a cheap (consumable) part to replace.
Our heating engineer has never mentioned or tested the capacitor.

Boiler still working, haven’t had to take cover off since fitted capacitor. So I’m ruling the air bubble out as the cause of lockouts.

 

[SJB060685]

I work in mechanical engineering and have a basic understanding of electrics, hence reason off checking/replacing capacitor also that it’s a cheap (consumable) part to replace.
Our heating engineer has never mentioned or tested the capacitor.

Boiler still working, haven’t had to take cover off since fitted capacitor. So I’m ruling the air bubble out as the cause of lockouts.

As you were told by technical it's common to find an air bubble in these hoses, as long as its static and not impeding oil flow then you never have to worry. Yes one could fit a tigerloop or any other deaerator if they felt compelled but I was under the impression this would void any warranty supplied with the HRM boilers anyway.
With regards to the capacitor if you have a background in mechanical engineering then theres really no need for my to give you a run down on how it works and like you said they're a few quid, so easily justifiable.
What worries me about your current engineer (or ex) is this is day one stuff. Usually when a capacitor is on it's way out you can tell on initial burner start up. Although individual electron flow is minuscule in speed the affects of electricity are almost instant and if you had a faulty capacitor when theres a demand for heat the motor would lag for a split second before ramping up, whereas a healthy capacitor it would spin with no latency. Know this and when you're servicing a boiler you should be picking up on it.
For future reference I was always told to replace a capacitor 70% and below original microfarad rating, ie, if it's a 5uF capacitor then replace if its 3.5 and lower.

 

[Simonvr46]

Thank you for your reply.
You guys have been really helpful in confirming my diagnosis of our boiler.

just a case of waiting and hoping it continues starting up when a demand for heating is required.
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Boiler came on at 7am until 8am for the other half getting ready for work. I’ve just gone to put heating back on and boiler has locked out..... 1st time in a week it’s done it. Started up on 1st press of reset button.

 

[SJB060685]

Oh ffs. Right instantly I'm thinking of a couple things but it could be a number of components being the problem child. To help you further over the forum could you tell us what the burner is doing, trying to do at point of lockout? A video showing point the burner fails and fails to reestablish would be very helpful.

 

[Simonvr46]

Oh ffs. Right instantly I'm thinking of a couple things but it could be a number of components being the problem child. To help you further over the forum could you tell us what the burner is doing, trying to do at point of lockout? A video showing point the burner fails and fails to reestablish would be very helpful.

What are the things your thinking it could be?
I’ll try get a video next time.

 

[SJB060685]

I'm thinking MAYBE a sticking pump or bad bearings, although that's just speculation. It could be a number of other things though. A video so I can see and most importantly hear would help massively, although this being intermittent it could be a while before you can catch it on video. You could get lucky in 5 minutes, it might take a lot longer. When these burners lose flame they automatically go through a re ignition cycle before lockout occurs, ideally to get a good idea I could do with a video showing all of it.

 

[Simonvr46]

quick update, boiler failed to start this morning when other half was getting ready for work but restarted on 1st press of button. Boiler came on at 4:30pm without issue.

 

[SJB060685]

Ok. Providing the new capacitor is healthy then I assume this is not the culprit. I'm assuming it's not fuel related as if it were it would usually be more frequent. It could be as I said a few posts above or it could be another electrical fault. It's not helping either of us by being intermittent and starting first push on reset button.

 

[Simonvr46]

Ok. Providing the new capacitor is healthy then I assume this is not the culprit. I'm assuming it's not fuel related as if it were it would usually be more frequent. It could be as I said a few posts above or it could be another electrical fault. It's not helping either of us by being intermittent and starting first push on reset button.

It’s very frustrating. Not many more electrical components to change.

If it was an electrical fault, could it be electrical fault with the motor? If so can this be tested in any way?

With regards to the pump you mentioned in earlier post can that be checked?

 

[SJB060685]

The motor is a simple device as you know, a rotor with permanent magnets, primary and auxiliary windings and two sets of bearings. Yes the resistance of motor primary and auxiliary windings can be checked but without knowing what burner it is and finding the correct info either online or phoning technical I couldn't tell you what the readings should be. If these readings were off you could experience similar to a faulty capacitor where the motor could stall.
To check if you have a tight spot on the pump someone would have to isolate fuel and remove pump and components, then by hand spin the shaft to see if there were any tight spots, that would also be the time to spin motor shaft to see if bearings were good and check pump coupling isn't sheared.
However this requires competence and confidence.
The best I can say now is bring on the boiler at programmer (HW or CH) and then go to burner and isolate the rocket switch, then give the burner lots of work to do by switching switch on and off. Turn on and see if ignites, if it does then off and on again until it hopefully fails, by doing this you're effectively bullying it into making a mistake, if it does make note of what happened and most importantly didn't happen.
NOTE these rocker switches are notorious for failing themselves so don't try this too much or too often, the last thing you need is to replace a switch before checking everything else can continue.

 

[DaveyHep]

I assume you’ve set the burner up. What flue gasses are you getting?
If you’re getting too much air it can cause intermittent ignition problems.

 

[Simonvr46]

Hi it’s a sterling burner
Failed to start this afternoon. I’m hoping you can view video I took.
As for flue gases it’s running ok according to heating engineer. I have the sheet from when I was serviced, I’ll have look for it.

 

[SJB060685]

I hear pre purge and solenoid click, fuel flows and sounds like ignition, then it sounds and looks like fuel stops flowing and burner stops a second before lockout. What parts did you say were changed?
At the moment I would be checking what the pressure does moments before flame stops, you could have a dodgy coupling slipping or the pump drive keys is on it's way out. The capacitor and motor seem fine and to answer one of your previous questions I would check to see if the old capacitor is screwed into motor frame, it looks like theres a collar there but I cant remember off the top of my head.

 

[SimonG]

I'd be checking electrode position, once had to fit a burner upside down due to this, don't ask me what difference it should make, but it ran like a train after.
Also at excess air as DaveyHep was alluding to a couple of posts back.

 

[SJB060685]

I'd be checking electrode position, once had to fit a burner upside down due to this, don't ask me what difference it should make, but it ran like a train after.
Also at excess air as DaveyHep was alluding to a couple of posts back.

I don't want to argue Si because I know you're competent but have a look and listen to the video. I'd be checking what I said first as its clearly igniting, yes electrodes and air affect these as we all know but the video is telling me more than that.

 

[Simonvr46]

I hear pre purge and solenoid click, fuel flows and sounds like ignition, then it sounds and looks like fuel stops flowing and burner stops a second before lockout. What parts did you say were changed?
At the moment I would be checking what the pressure does moments before flame stops, you could have a dodgy coupling slipping or the pump drive keys is on it's way out. The capacitor and motor seem fine and to answer one of your previous questions I would check to see if the old capacitor is screwed into motor frame, it looks like theres a collar there but I cant remember off the top of my head.

Components changed so far are capacitor, clear hose, fire valve/nrv, photocell, solenoid and ebi transformer. Also DKO control box replaced in 2012 but was doing this prior to this. Boiler was serviced in September.

 

[SJB060685]

So this has been a problem since 2012?

 

[Simonvr46]

So this has been a problem since 2012?

Yeah pretty much, I’ve been with other half 5 years and we had mainly used immersion heater for hot water and kept pressing reset to get boiler started for heating or used log burner in living room.

 

[SJB060685]

From what I've seen and heard from video is its igniting, then theres a loss of flame during safety time and it's going to lockout. It could be as Simon above suggested about air it could also be what I said. Have you taken black cover off the front to expose air damper adjuster and made a note of what setting it's on.

 

[Simonvr46]

I'd be checking electrode position, once had to fit a burner upside down due to this, don't ask me what difference it should make, but it ran like a train after.
Also at excess air as DaveyHep was alluding to a couple of posts back.

Boiler sometimes will work ok for 7 days before it suddenly locks out.
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From what I've seen and heard from video is its igniting, then theres a loss of flame during safety time and it's going to lockout. It could be as Simon above suggested about air it could also be what I said. Have you taken black cover off the front to expose air damper adjuster and made a note of what setting it's on.

I’ve taken photo and attached it.

 

[SimonG]

I don't want to argue Si because I know you're competent but have a look and listen to the video. I'd be checking what I said first as its clearly igniting, yes electrodes and air affect these as we all know but the video is telling me more than that.

Difficult to tell with TV going full tilt and granddaughter trying to drown the telly out with her tablet. Not a fan of listening to videos for diagnosis.

I did hear fan, good spark but the ignition sounded a bit muffled.

Also good to see that we are not having to wait now to get answers.


Plus the golden rule, just because it's new out the box, doesn't mean the new part is good. Seen a few new parts being faulty.

 

[SJB060685]

It looks like it's in the right area but without test equipment i couldn't say for sure. So help us further, how often have you been using the immersion and log burner? 8 years is a long time where if you were using the boiler more often the problem will have presented itself by now.

 

[Simonvr46]

It looks like it's in the right area but without test equipment i couldn't say for sure. So help us further, how often have you been using the immersion and log burner? 8 years is a long time where if you were using the boiler more often the problem will have presented itself by now.

the problem with the boiler has always presented it self, it’s just that we’ve made do with it and worked around it.
We thought it had been sorted when we had those parts replaced, it’s mainly winter that we have the issues as using boiler more for heating.

can’t get boiler to start up this evening......

 

[SimonG]

Just going straight to lockout?

 

[Simonvr46]

Just going straight to lockout?

Yeah it’s trying to start up like in the video and just keeps locking out.

 

[SJB060685]

Solenoid click but no ignition?

 

[SimonG]

Stick a couple of fingers over the air intake on the burner to see if it fires. Don't block it just reduce the amount of air its pulling in.

 

[Simonvr46]

Stick a couple of fingers over the air intake on the burner to see if it fires. Don't block it just reduce the amount of air its pulling in.

Tried that but made no difference, pressed reset button again and let it start as normal and it started. I’m totally confused.......
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Solenoid click but no ignition?

Yeah think so, can see pump drawing oil, transformer is sending spark to electrode and then goes lockout.

 

[SJB060685]

From what I've seen, heard and read I'm still leaning towards a pump issue. I'm not saying it is but it's what I'd run a couple tests on first. To prove or disprove ignition and atomization things have to be done but I'm not going to say what. It could be air related as well but I'm not convinced.
I cant say anymore, from here on in it needs a decent engineer with good experience and the right gear.

 

[SimonG]

Have you taken the burner out before?

If you have, take it out and take a picture looking down the blast tube. Make sure you unplug coil or turn it all off.

 

[Simonvr46]

From what I've seen, heard and read I'm still leaning towards a pump issue. I'm not saying it is but it's what I'd run a couple tests on first. To prove or disprove ignition and atomization things have to be done but I'm not going to say what. It could be air related as well but I'm not convinced.
I cant say anymore, from here on in it needs a decent engineer with good experience and the right gear.

Ok no probs, thank you for your help.
Going to give someone local a ring tomorrow for advice before getting them to come visit.
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Have you taken the burner out before?

If you have, take it out and take a picture looking down the blast tube. Make sure you unplug coil or turn it all off.

No never taken burner out before. Although I work as a mechanical fitter im not confident with taking burner apart.

 

[SimonG]

No problem, respect somebody who knows there limits.

Was the nozzle changed at the last service?

Whereabouts in the country are you?

 

[SJB060685]

By all means update us if you get a result.

 

[Simonvr46]

No problem, respect somebody who knows there limits.

Was the nozzle changed at the last service?

Whereabouts in the country are you?

Will give most things ago but know when I’m at my limits lol.
Yeah nozzle and filters was changed last service.
Im in Lincolnshire.

 

[SimonG]

Too far for me. Hope you find somebody to sort it and please let us know what the problem was.

 

[Simonvr46]

By all means update us if you get a result.

Yeah sure will. Hopefully if I get sorted I’ll be able to pass on my fix to someone else.
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Too far for me. Hope you find somebody to sort it and please let us know what the problem was.

Bacon, sausage and egg butty???

 

[Best]

Fool the photocell into seeing light once burner fires and see if burner continues to fire while photocell out. Handy on Sterling burners.
That will prove flame is poor for some reason or photocell had obstructed view.
Does sound like flame burn is barely making it

 

[Simonvr46]

Fool the photocell into seeing light once burner fires and see if burner continues to fire while photocell out. Handy on Sterling burners.
That will prove flame is poor for some reason or photocell had obstructed view.
Does sound like flame burn is barely making it

Boiler started up 1st attempt this morning.......

I did try this awhile ago. I think when I removed photocell burner continued running but when I covered photocell it shutdown if my memory serves me correctly.
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Took burner unit off and had a look. I’ve attached photos. Tip of nozzle is damp with oil.
Any suggestions?

 

[Best]

Boiler started up 1st attempt this morning...

I did try this awhile ago. I think when I removed photocell burner continued running but when I covered photocell it shutdown if my memory serves me correctly.

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.

 

[SimonG]

Nozzle being damp is fine. Dont like the position of the electrodes though.

 

[Simonvr46]

Nozzle being damp is fine. Dont like the position of the electrodes though.

Just a quick question, the capscrew that is in the main body of the burner just below the black plastic cover for the photo cell etc is that what is undone when boiler serviced? If so should the gasket be replaced?
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could the electrode be causing the issue of lockout? If it’s not positioned correctly could the photocell fail to detect it sometimes?

is the blast tube ok or should that be cleaner?

 

[SJB060685]

The Alan key under the black cover is used to undo and remove the burner, you've detached the whole thing. The electrodes don't look right in terms of position and could be part of the reason it doesn't light sometimes, it doesn't explain why it sometimes ignites and then loses flame during 5 second safety time though.

 

[Simonvr46]

The Alan key under the black cover is used to undo and remove the burner, you've detached the whole thing. The electrodes don't look right in terms of position and could be part of the reason it doesn't light sometimes, it doesn't explain why it sometimes ignites and then loses flame during 5 second safety time though.

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.

 

[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.

 

[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?
[automerge]1580922432[/automerge]

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.

 

[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.

Your correct about the YouTube video, 5Nm for external Allen screws and 3Nm for the 3 internal screws.

 

[SJB060685]

Your correct about the YouTube video, 5Nm for external Allen screws and 3Nm for the 3 internal screws.

There you go, I knew I had seen it somewhere

 

[Simonvr46]

New heating engineer came and replaced the pump, after speaking to Danfoss they recommended fitting BFP21L3 instead of the BFP11L3, heating engineer set pump pressure at 120psi and used FGA to set burner up. All running spot on.
Next morning burner locked out.
Heating engineer been back and resealed all the joints in pipe work with oil seal.
Burner still locking out, but starting after reset.

This evening boiler won’t start.....

Could it be electrodes??

 

[SJB060685]

Remind me again what parts have been replaced?

 

[Simonvr46]

Remind me again what parts have been replaced?

Transformer, pump, capacitor, nrv/firevalve, photocell, solenoid and the control box (7years ago its now a dko).

 

[SJB060685]

Christ that's virtually everything. Yes if the electrode gap is wrong or dirty electrodes it could fail to ignite. If it was arching elsewhere other than at electrode ends then the photocell will usually detect false light and not even open the solenoid for ignition and go straight to lockout. Has this been checked? When the pump was replaced was the coupling checked and/or replaced? You could still be experiencing an excess of air at times if seals were perished as we've discussed before. I have a feeling you might have more than one issue still but of course I could be wrong.

 

[Simonvr46]

Christ that's virtually everything. Yes if the electrode gap is wrong or dirty electrodes it could fail to ignite. If it was arching elsewhere other than at electrode ends then the photocell will usually detect false light and not even open the solenoid for ignition and go straight to lockout. Has this been checked? When the pump was replaced was the coupling checked and/or replaced? You could still be experiencing an excess of air at times if seals were perished as we've discussed before. I have a feeling you might have more than one issue still but of course I could be wrong.

Yeah not much left to replace, the coupling was replaced with new pump.
New engineer says that the excess air amount that’s registering on FGA is ok.
He looked at electrodes when he had burner apart and said they look ok, couldn’t see any sign of arcing other than where should be.

 

[SJB060685]

Has he checked thoroughly though rather than just saying it looks ok? Someone I know had this recently where it was only intermittently arching elsewhere. You got fuel, you got new pump and coupling I know what I'd be looking at next.

 

[Simonvr46]

Im going to speak to him tomorrow, see what he suggests and I’ll enquire about the electrodes.

 

[SJB060685]

When it doesn't start at all do you hear the solenoid click?

 

[Simonvr46]

When it doesn't start at all do you hear the solenoid click?

Yeah solenoid clicks and pump draws fuel, then few seconds later boiler goes lockout.

 

[SJB060685]

So when it doesn't start at all the motor runs, you hear solenoid click and see fuel flow but it doesn't ignite at all? If that's the case I'd suspect its ignition related. Electrode gap wrong, dirty electrodes, weak HT leads, weak spark from ebi transformer or arching elsewhere, porcelain electrode covers need to be checked. Control box possibility as well

 

[Simonvr46]

So when it doesn't start at all the motor runs, you hear solenoid click and see fuel flow but it doesn't ignite at all? If that's the case I'd suspect its ignition related. Electrode gap wrong, dirty electrodes, weak HT leads, weak spark from ebi transformer or arching elsewhere, porcelain electrode covers need to be checked. Control box possibility as well

Yeah motor runs.
Sometimes it runs perfectly other times it fails to ignite.
Electrode gap is ok, transformer replaced recently due to weak spark. Control box replaced 7 years ago.

 

[SJB060685]

It's one of those where theres only so much I can do through a phone for you. If I was the engineer attending and based on what you've said (assuming I haven't misread you) is I'd be looking at ignition first. I say that because motor is clearly running, you say you hear solenoid click and see good neat fuel flow, so saying that it's either an over aired problem (which by now we think not) blowing spark away from nozzle, a problem with the ignition, be it arching elsewhere etc, or a problem delivery the fuel. I've never experienced it but those that have taught me always consider a blocked HP line from pump to nozzle outlet as well.
I can tell you how to safely check spark function and quality but its probably best left to the engineer, I do not want to be responsible for something you got wrong.

 

[Simonvr46]

It's one of those where theres only so much I can do through a phone for you. If I was the engineer attending and based on what you've said (assuming I haven't misread you) is I'd be looking at ignition first. I say that because motor is clearly running, you say you hear solenoid click and see good neat fuel flow, so saying that it's either an over aired problem (which by now we think not) blowing spark away from nozzle, a problem with the ignition, be it arching elsewhere etc, or a problem delivery the fuel. I've never experienced it but those that have taught me always consider a blocked HP line from pump to nozzle outlet as well.
I can tell you how to safely check spark function and quality but its probably best left to the engineer, I do not want to be responsible for something you got wrong.

It’s very frustrating with it being intermittent. The other half is getting annoyed and stressed with it.
Yeah that would be great if you could tell me how to check spark function and quality.
I work in engineering so have a good practical skills background but know my limit and when to get In professionals.