Miller CMF-80 PO oil leak

[Steve S.]

Hi All,
Have a slight problem with my K1-fired burner dripping fuel from nozzle(I think) and out the bottom of burner housing/air shutter. Furnace runs fine otherwise, just an inconvenience to keep cleaning burner housing every 3-4 cycles because of the unpleasant smell. Furnace ran leak-free last heating season...the only changes being a recent delivery of fuel and an earthquake in mid-October. Took the gun assembly out, cleaned and replaced nozzle with same size, dammed the space between the air tube and burner housing...but it still leaks. I'm wondering if I got a contaminated batch of fuel...I'll try cleaning/replacing pump screen next.
Anyone have any ideas on the cause of nozzle leaks??
Cheers, Steve

[Greg]

New nozzles are not that expensive, try a new one. It may be a chunk of crud causing the spray to be off center and causing a drip rather than burning it. Many have a copper gasket that seals it in the threads, that may be leaking also. You could also just take it a part and try cleaning it, make sure everything is tight when you put it back together.

Greg

[Steve S.]

Hi Greg,
Thanks for the reply...I've tried different nozzles and cleaned up the gun assembly really well. I'm beginning to think that the pump seal may be leaking...it's very hard to locate leaks within the burner housing when you have that fan inside there slinging fuel everywhere...that red dye makes things pretty messy. This old Miller furnace has given me nearly 30 years of good service, I've been keeping up on the maintenance, filter changes, and cleaning. I think maybe I'll replace the pump and see if that makes a difference.
Cheers, Steve

[Greg]

If there is any trace of fuel farther back than the end of the gun, than it is probably not the nozzle. I would think that any leaking fuel would be blown forward by the fan.

Greg