On Thu, 16 Oct 2003 18:08:26 -0400, "CBHvac"
wrote (with possible editing):
....snipped most
Depends, and I mean, depends.
IF you have 20 feet of indoor line, and 10 feet of outdoor, maybe..and I
mean..MAYBE.
We have about 60' of 2, 1/2" lines to one location, and about 30' of
3/8" lines to another.. The 2000 gal tank is in a concrete bunker
buried in a hillside and covered with an insulated roof. The pipes
are in trenches about 3 feet deep and sandwiched between 2 layers of
2" polystyrene. The shorter run goes indoors 10' to a hot air
furnace, the longer goes indoors maybe 15' runs the boiler and diesel
generator.
He claimed that the oil had to be over 50 degrees for some reason or
another so he switched us from a double to a single line system, but
since he was never able to cure the hard start, I have no idea if he
was correct.
Funny how all the oil burners here work just fine when you have a couple of
weeks in the teens...
Not here. It started hard regardless of temperature.
At my location, another reason for switching to the one line system
was that our diesel generator was tied into the same line. The last
tech cited the above as yet another reason for switching to single
lines. He put the generator on one line and the burner on the other.
The generator was setup for two lines, but fortunately nothing comes
out of the return line, so we stuck it in a 5 gallon pail and check it
occasionally.
Then its not set up at the pump for two lines, and I suggest that you either
remove the second line and cap the pump with the plug that should be there,
or get it set up for a dual line and get it ran out to the tank.
IF that pump fails, you are going to be vEEEEERy surprised at how fast a 5
gallon pail fills on that small line.
Actually, if the pump fails, nothing will happen as the pump is
required to pressurize the injectors on the diesel. The return line
is apparently connected to something which resembles a manifold (but
isn't)
The diesel is a Mitsubishi. Both the Mitsubishi manual and Gillette
who coupled it with their generator say to use two lines. Since
nothing comes out of one, I asked a diesel mechanic what was going on.
He told me that the way this diesel was setup, nothing NORMALLY will
come out the return line. However, as the machine ages, we might get
some blow by from the injectors into the "manifold" and that was what
the 2d line was for.
Since the second line is normally empty, it ruled out the way it was
setup - the feedline for the boiler was used as the return line for
the genset and vice versa. The problem was that the boiler could suck
air through the genset return line - you couldn't add a check valve.
I thought we could plumb it so that there was a common feed and return
to both, but the last burner tech (the guy who actually cured the hard
start) said that was unreliable. Why? I have no idea, but it
appeared that, according to him, to have both units on one line, we
had to run one more line and I didn't want to do that.
What we may do is put a 55 gallon drum in the room and let it fill
with a check valve. Then we can have both the feed and the return
from the generator in that. Naturally, I have monitors watching the
floor of the utility room for both oil and water - I don't know
anything about boilers, but as a retired EE, I do know a bit about
electronics.
--
Larry
Email to rapp at lmr dot com