HRM Wallstar Oil Boiler - Advice please

[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.

 

[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.