danfoss bfp 21l3 oil pump

[abreng]

hi any advice-the danfoss oil pump seized on boiler-picked up new one locally and fitted-ran for 6/8 hrs found on lock out-this one also now seized-filter is spotless-fan drives well(no bearing/shaft wobble).any ideas welcome

 

[Boilerman2]

Fit a Vacuum guage to the "V" port if you are pulling much more than 0.5 then expect trouble, this would indicate a blockage in the fuel supply pipe such as a nearly closed valve, a tripped fire valve, blocked line filter etc etc is this boiler on a one or Two pipe oil supply and is there a de-aerator (Tigerloop)

 

[abreng]

hi,thanks for reply.had day off (total nightmare).heres what i done-removed old filter at tank and replaced for new after flushing out from tank,through filter housing.blew air line from pipe which connects suction on pump-through to outlet from tank filter,bled nice clean oil into bowl nice flow clean oil.then reconnected pump with vacuum guage-it bliped to 0.2 for a second as i bled it then 0 all of the time.pump still sticks-contacted danfoss they suggested alignment so replaced all couplings/drive dogs with new from local supplier,fan bearing ok as fan runs free and true.still sticks.cleaned all outlet pipework to burner and replaced nozzle for same but new,still sticks.got supplier to change pump as suspect,still sticks.please help before i smash with hammer.thanks .

 

[Burnerman]

When you say 'sticks', does the pump actually lock up solid or easily come free again?
John

 

[abreng]

hi,pump sticks goes out on lock out,sometimes resets and goes after 5/10 mins,sometimes remove pump and work drive back and forth and try again,sometimes remove back of pump blow out and lube(wd40)as working back/forth and refit.then runs for between 10 mins and couple of hours.thanks antony

 

[Boilerman2]

What make & Model is the Oil Burner
and what make & Model boiler is bolted to?

 

[abreng]

hi-ok burner-bentone ab-boiler is thorn panda 2 19kw

 

[Boilerman2]

Check the alignment of the coupling between the opposing motor & pump drive shafts, this is critical (no tight spots), the black section of coupling may be a bit too long? it should not have too much slack horizontally between the drive dogs, but it should not be so tight that the pump has to be "forced" fully home into the burner.

And finally make sure that the Drive dogs are not worn the one on the pump has a flat to match the flat on the pump shaft, if this is worn the dog can slip on the shaft and cause problems

Alignment can be achieved by a carefull & even tightening of the two grub screws that hold the pump to the burner

 

[abreng]

thanks for info-this is what i thought so today bought new rubber coupling and fan drive and pump drive dogs.fan drive dog sits loose on splines over fan hub so no adjustment-cut rubber(squarely)and other drive on pump slides over flat to a set stop position so i have measured with vernier so that pump drives sits into rubber a good 5mm short of the end.so should be good.once motor and pump bolted up is there a way of hand turning motor/fan to see if tight spots as motor enclosed type.i appreciate your time in helping me out.

 

[Burnerman]

I've got a Panda boiler and I love it to bits.....
The splined coupling that fits over the motor drive is prone to failure, and cut the splined drive exactly the same length as the original.
The only thing I can think of is that the pump is located with 2 allen screws - I keep mine hardly tight in case there's a chance of the pump being forced out of alignment.
Obviously these pumps rely on a source of kerosene to keep them lubed - so does the burner actually run?
There's no real way of spinning the pump assembly as the fan cant be reached, really.
I have had an issue with another burner recently - the motor would spin grand on the bench, and start up every time - but give it some load (i.e hold with the fingers) it had no turning force at all.
John

 

[abreng]

pump runs sometimes 10 mins sometimes 2hrs. had one last go for the evening 2 hrs ago i did slacken off those two grub screws though, so as boiler still on fingers crossed-cant believe such a fine line.thanks again though for info.at least everything fully checked/changed.

 

[Burnerman]

Seriously I would have thought that the 3 part motor to pump coupling would have enough flex in it to compensate for any slight misalignment but I haven't experienced your particular problem.
I am wondering though when the burner locks out, whether its the motor, or rather the motor capacitor doesn't have enough oomph to get things spinning again.
Keep us informed!
John

 

[Boilerman2]

Over my 36 year career as a boiler service engineer, i can tell you these couplings can be a pig to set correctly on occasions I think you have been lucky not to have had too many problems, mind you you don't see so many Inter Burners around now, in the 1980's they were fitted to 90% of all new boilers!!