oil burner problem..well panic!

[mikethepipe]

Hope someone can help,I've got a burner problem I've never seen.Old camray quartet,Rielio burner,seems to have had multiple faults.Conrol box burnt out-wisps of smoke,replaced it and base plate.
Capacitor low value on motor,replaced.
Water in oil tank,drained and tested clear with paste.
2 filters fitted,one at tank,one near boiler,both new.
Tested oil for water at pump connection,clear.
The pump seized after a couple of hours firing,I'm thinking caused by water before it was sorted,replaced pump,which looks like it's going the same way.
Absolutely stumped,I'm retired now but have seen many faults,but not this pump seizing/overheating??problem...could the filters be too much restriction,so the pump is having to work too hard?
Nozzle replaced,and pump pressure fine when the pump is working,flame is clean and normal.
Must be obvious,but I can't see it....help please.
Thanks.
Mick.
Ok,so the pump is getting hot,as is the motor,The motor spins freely and starts fine after the "hot and sticking) pump is removed.
Double checked for water with paste,looks clear and perfectly mormal.
Combustion completely normal.
So something is making the pump overheat,I'm guessing these run on very close tolerances and any excess heat will close tiny gaps...maybe?
Does anyone know if motor and pump should run fairly cool,it is near a heat source afterall?
I don't have a vacuum gauge,but am wondering if the new filters are giving too much resistance?

 

[oilhead]

If on a 1 pipe oil supply, you should have a gravity flow to the burner. Is your pressure gauge reading steady? If so it's doubtful if the oil supply is the problem. If you remove the pump filter, is it clean? You may have pulled sufficient contamination through to sieze it. Is your new pump marked 'Bio' ?
At the end of it all, yours would not be the first faulty Riello pump out of the box.

 

[mikethepipe]

Thanks for taking the time oilhead.
The box is marked B 10, I'm guessing this is not the same as "bio" ,I read that bio fuel can damage regular pumps,but our fuel is just regular heating oil.
1 pipe system,there was muck in the line ,but ran it from the tank until clean then installed two of the paper element type filters.
The weirdness is the second new pump,installed after the line was clean and tested for no water seized solid after an hour,( internal pump filter clean) it had got hot,along with the motor,I then put in yet another new pump,after checking again for water,and it started to get hot too....the flame had normal combustion values and textbook appearance.
So I was thinking there might be a restriction in the line underground that was making the motor/ pump work too hard.At the moment I can run the burner for short periods,say 10 minutes before the pump heats up.
I don't have a vacuum gauge so I will get one so I can check the supply line.
The motor gets very hot if the burner is on for say 30 minutes,which only happens on start up from cold,I don't know how hot it got before though as I never had cause to check it.I think it's unlikely to be a faulty motor overheating and transmitting heat to the pump though,too much of a coincidence.
The gravity flow rate is reasonable,I've seen similar flows that work fine..I think...but I'm beginning to doubt my judgement!
Must confess it's been a bit of a nightmare,any extra thoughts would be much appreciated.
Thanks.

 

[oilhead]

B10 is the current pump. The green shaft seal shows this.
The motor will spin at its design speed, so thus will the pump. Both motors and pump get hot in use. Obviously its not possible to know how hot yours is. If the pump was struggling for fuel, I would have thought there would have been evidence such as re-ignition. If the 2nd pump came from the same merchant, its possible that there could be a bad batch. You are obviously familiar with the boiler, burner and combustion process but we all know how a persistent problem can cause self doubt.

 

[mikethepipe]

Thanks again oilhead.
I will take the first seized pump back to see what the warranty policy is,but Riello are understandably wary about warranty claims.
I think I'll run up the motor with no pump to see if it gets hot on its own,but there's no load so that isn't really a good test.
Might get a pump from a different source and let the system start from cold to see if it gets tight.
Thanks for the advice re restricted supply,I don't really understand the exact mechanism by which the pump generates the pressure,but as you can have a return pipe I wondered if the pump actually needs a fairly high flow but only sort of "uses" part of it,returning the unneeded flow within the pump somehow.
Anyhow I think I'm inching closer to an answer.
Much appreciated and happy Christmas!

 

[oilboffin]

Whoops steady my friend this burner is costing you too much get in touch with heating world of spares and get another burner brand new get a tech to fit it and set it up also you've still got water in the oil pipe get it blown out as water and oil can share a pipe water at bottom and the oil pulls the water with it and it will jigger a pump so the pipe needs to be clear.Bob

 

[mikethepipe]

Thanks Bob,your help and thoughts much appreciated.
It's running fine at the moment,having a day or two off before committing any more time/ money,it's a character flaw really,I started life as a mechanical engineering technician and the drive to always fix not replace where possible is hard to shake off!
Thanks again.