Pump Problem on Worcester Heatslave

[Robert Tyrrell]

I got called to a breakdown on a Greenstar Heatslave 18/25-OSO-GB yesterday. It had been playing up, intermittently for about 2 weeks - why do people wait until these things escalate?

Anyway. I got there and investigated, starting with the tank filter and working backwards (Based on the symptoms as explained by the customer) but couldn't find a reason for the lockout, at this stage, so I thought I'd check the pump/fan.
Took the pump off and checked it, and the fan at the same time. Put it back together and replaced the burner.
When I turned the oil supply back on, it flooded straight through the pump into the combustion chamber!
Anyone come across this before, and if so how was it remedied please?

I am going away for two weeks on Friday and would like to get my customer's hot water working for them before I go as they are a regular service customer of mine.
Thanks

 

[SimonG]

What burner. Dodgy fuel pump stem. Change nozzle, change stem and go from there.

 

[Gazzt]

Yes i agree with simon g sounds like oil pump solenoid valve, also oil pumps can leak through the drive seal. ( where the pump connects to the motor on riello) or ( where danfoss pump connects to the plastic drive between the motor).

 

[Gazzt]

What are the symptoms the customer described ?

 

[Old Account]

Perhaps @Best could help you out he's got a lot of experience about things like that.

 

[rpm]

Perhaps @Best could help you out he's got a lot of experience about things like that.

You will find SimonG has as well.

 

[SimonG]

Really need this sort of query from a professional away from the general public. Laws are different for gas and oil but unfortunately the outcomes are not.

Good example. Local pub ran out of oil, I went out, found allen keys and screw drivers in the bottom of the burner. Bled the oil through and fired first time. Analyser in and the carbon monoxide was on its way to 3000ppm and all because somebody had adjusted the oil pressure by mistake.

Robert, get yoursen in t'arms

 

[Gazzt]

Most common callout in winter is the homeowner trying to bleed the oil through the pressure adjustment screw. The black soot pouring out of the flue and a smell you cant get out of your van for weeks with a dirty hoover and flue brushes.

 

[SimonG]

Most common callout in winter is the homeowner trying to bleed the oil through the pressure adjustment screw. The black soot pouring out of the flue and a smell you cant get out of your van for weeks with a dirty hoover and flue brushes.

Did three in a week about a month ago. The hoover and van still stink

 

[Gazzt]

Its the most annoying breakdown, its so messy.

 

[Best]

Its the most annoying breakdown, its so messy.

Worst thing is everything you have touched will be black.
Cleaner hose and every screwdriver or spanner.
Then you go to install a nice shining white new electric shower next day and transfer black soot onto it.
Really need a set of tools solely for oil boilers.
I think those pressure adjustment screws on oil pumps should be made with anti tamper covers to stop a diyer turning it easily.
I put a piece of black electrical tape over the pressure adjust Allen screw on Danfoss 21 and 41 pumps

 

[Robert Tyrrell]

What burner. Dodgy fuel pump stem. Change nozzle, change stem and go from there.

It's a Bentone Sterling burner that's 8 years old.
I think that the nozzle stem could be the problem as there appeared to be evidence of tampering on a few of the allen bolts.
I have a spare burner for just this kind of scenario so I will fit the new one, and charge them for it because I don't have the time to strip the burner and repair it. I'm trying to get all my work up to date before I go away for two weeks

 

[Best]

Just put a new oil pump and nozzle on the burner and that should solve it all. Should only take a few minutes and then set it with analyser.
Fitting a spare burner probably won't be any quicker.
On the subject of leaking oil pumps, I notice motor bearings are failing on burners that have the direct pump to motor close connection. It is due to kerosine getting at the first bearing and often almost undetectable passing from the oil pump shaft seal. The Kerosine slight weep tends to evaporate. All Riellos and also burners like Bentone B9, Minor 1, etc will have this problem. I often wondered why the old design type burners, including the Sterling burners that have the rubber shaft drive were rarely having bearing failures, but now sure it is because they are not close to kerosine

 

[rpm]

Just put a new oil pump and nozzle on the burner and that should solve it all. Should only take a few minutes and then set it with analyser.
Fitting a spare burner probably won't be any quicker.
On the subject of leaking oil pumps, I notice motor bearings are failing on burners that have the direct pump to motor close connection. It is due to kerosine getting at the first bearing and often almost undetectable passing from the oil pump shaft seal. The Kerosine slight weep tends to evaporate. All Riellos and also burners like Bentone B9, Minor 1, etc will have this problem. I often wondered why the old design type burners, including the Sterling burners that have the rubber shaft drive were rarely having bearing failures, but now sure it is because they are not close to kerosine

What sort of bearings are we talking here guys? Shielded with grease inside or open faced with or with the grease (Oil lubrication?).

 

[Best]

What sort of bearings are we talking here guys? Shielded with grease inside or open faced with or with the grease (Oil lubrication?).

Grease doesn't seem to prevent Kerosine getting into and damaging the bearing. Although I have fixed dry bearings in the past with grease, when I didn't want to remove them, or didn't have same size. Most bearings I am talking about have a snap in plastic cover, but some are open encapsulated bearings, not that either will be sealed to Kerosine.
Clearly the oil pumps let Kerosine past slightly. Never had much bother with bearings on motors that are far apart from the oil pump, being driven by a rubber drive.

 

[rpm]

The one`s with plastic shields you can re grease others with metal shields you aren`t meant to and normally damage the shields getting them out and back in. Haven`t done a lot of Kerosine pumps aren`t there lip seals or do they not really work?

Have a story about a kerosene pump I reconditioned for the navy and due to misalignment of the drive it only lasted a few hours, There fault not mine I hasten to add.

 

[Gazzt]

Riello 40 burners eat bearings, i replace the bearings with the expensive sks bearings, also i noticed hwos sell bearings specifically for use close to the oil pump, they seem to have a different seal.

 

[Gazzt]

I think heat transfer from pump to motor or motor to pump has alot to do with it in my opinion.

 

[rpm]

There is a wide range of bearings out there some cheap and some expensive, try talking to a supplier near you that are specialists in bearings and V belts drives.

 

[rpm]

I think heat transfer from pump to motor or motor to pump has alot to do with it in my opinion.

If the shaft on a motor or pump is getting hot there is something wrong, normally the bearings are damaged and transferring the heat along the shaft.

 

[Best]

I think heat transfer from pump to motor or motor to pump has alot to do with it in my opinion.

I also had wondered was it due to heat transfer.
Maybe kerosine and heat are two causes.
When you look at the shaft seal on oil pumps, it is not surprising that kerosine will leak slightly past the shaft, particularly when oil pump is working and if oil pump is old. I recently had a careful look at a Riello burners oil pump using a torch and noticed very slight trace of kerosine down in between shaft and seal. Motor bearing had gone and that's what I think was causing it.

 

[rpm]

When you look at the shaft seal on oil pumps, it is not surprising that kerosine will leak slightly past the shaft, particularly when oil pump is working and if oil pump is old.

Used to "metal spray" and machine back to size the shafts on big pump & motors due to wear from bearings spinning on shafts and oil seals going hard and causing damage.

 

[Best]

Used to "metal spray" and machine back to size the shafts on big pump & motors due to wear from bearings spinning on shafts and oil seals going hard and causing damage.

That's just too much like real engineering for me!
One tip I was told about installing new bearings is to mark the shaft where the new bearing will sit with a metal punch to make sure it won't spin on the shaft, which they tend to do with new tight bearings or old seizing bearings.

 

[Gazzt]

I service boilers at a engineering company that supplies bearings, he recommended SKS to me and i can tell you they are far better than cheap bearings and noticeable quieter and smoother when burner is running.

 

[Gazzt]

Thats cool rpm, where you an engineer or did you work on industrial stuff.

 

[rpm]

That's just too much like real engineering for me!
One tip I was told about installing new bearings is to mark the shaft where the bearing sits with a metal punch to make sure it won't spin on the shaft, which they tend to do with new tight bearings or old seizing bearings.

That was proper engineering but unworkable with small stuff.
The metal punch (center punch) will work however if the raised surface is then too big you can load the bearing causing premature failure as you can if the bearing spins on the shaft.
Loctite make bearing fit which takes up a few thousands of an inch if the bearing has been spinning on the shaft. How do you guys remove and fit the new bearings because doing that wrong can cause premature failure as well.

 

[Gazzt]

I oil the shaft then put the a small bearing puller on, pull the bearings off, i then clean the shaft, check for damage, seat new bearing and use old bearings to tap down the new bearing trying not damage the new bearing.

 

[rpm]

Thats cool rpm, where you an engineer or did you work on industrial stuff.

I service boilers at a engineering company that supplies bearings, he recommended SKS to me and i can tell you they are far better than cheap bearings and noticeable quieter and smoother when burner is running.

SKS & NGS (think that`s right, was 20 odd years back ) are the 2 we used.
Did my apprentice in a machine shop (lathes, mills, grinders etc), then moved to machine maint` when I got tired of being shackled to a machine all day then fell into refurbishing commercial pumps & motors followed by plastic pumps today.

 

[Best]

Loctite make bearing fit which takes up a few thousands of an inch if the bearing has been spinning on the shaft. How do you guys remove and fit the new bearings because doing that wrong can cause premature failure as well.

On Riello motors, the oil pump side can be too slack for the bearing and a slight bruise on the shaft keeps it tight.
I don't get too fussy anymore with burner motors, but just keep kerosine away from them and avoid damaging motor windings.
I use a bearing puller where possible and tbh I can manage to use two flat blade screwdrivers to prise the bearing on oil pump side off easily. Not professional I know, but does the job.
I use an old 1/2" brass ball valve tail to hit with a hammer to tap the new bearing on as it is perfect fit for centre of Riello size bearings.

 

[rpm]

I oil the shaft then put the a small bearing puller on, pull the bearings off, i then clean the shaft, check for damage, seat new bearing and use old bearings to tap down the new bearing trying not damage the new bearing.

If you work a lot with the same size bearings then ask a local machine shop to make up a hollow drift from Bronze, an Alloy or even hard Nylon / Plastic, the hollow centre to be a few thou larger than the shaft and long enough so you have a solid face to hit with your mallet, the face that rests on the bearing to be slightly larger than the inner race but smaller than the outer race.

 

[Gazzt]

Thats high precision work rpm. I am sure you have come across all sorts of faults in pumps and bearings over the years.

 

[Gazzt]

Best i bought a wiper arm puller online to pull the bearing on the pump side, the jaws are small enough to fit under the bearing, but if they are tight the screw drivers are the answer.

 

[rpm]

Thats high precision work rpm. I am sure you have come across all sorts of faults in pumps and bearings over the years.

Something like 90% of bearing faults result in pump failures.
The condition of the shafts and the housings holding the outer race are so important are all bearings are precision made.
End of sermon.