I have a Carlin 99FRD with a Monarch 0.75 nozzle on a 1986 Burnham V-13A-T
boiler for a FHW heating system in my own house.
In the past year the burner has started burning rough (rumbles). The rough
running starts with a heavy rumble on shut down and progresses to become
rough throughout the burn over a couple of days. I've always had my oil
company come out and check everything. They clean the unit, fire it up, and
it runs clean (no soot dot), 83% eff, and smooth with a good flame- for
about 2 weeks. Then it starts again with the burping shutdown.
I'm pretty handy, so I've started cleaning the unit myself (can't be paying
for a service call every two weeks). What is happening is the flame
retention head is completely caked in carbon. There is a black oily residue
on the nozzle with a discoloration on one side. I blow out the nozzle with
compressed air, scrape and clean the head, and I go another 2 weeks.
Any ideas what causes this behavior?
More info: The service guys say that if the burner were no good we wouldn't
be able to get a good flame to start with. They have tried a few things and
are baffled. I understand that Carlin had sent out a new tech bulletin on
this model that suggested changing the air tube length. They did that. This
one is now set at 2. There was a discussion that the oil line was clogged
with residue or gum so a 10 micron filter was added at the burner end of the
line. Then they thought the oil line was restricted by two filters so they
removed the 40 micron filter from the basket on the tank end of the line. I
took it upon myself to clean out the oil line with compressed air, filling
and backwashing it 3 times. I've got a plastic milk jug 3/4 full of some
pretty nasty looking black shit. But the last batch came out more pink than
black so I think the line is pretty clean. There was a lot of little flakes
and particles that stick to the side of the milk jug and don't wash off when
you swirl the stuff around.
Any help would be appreciated.