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oil to the oil storage tank during the burner off cycle period. Do not run suction or return line overhead, as
this greatly increases the possibility of air pockets, oil leaks, siphoning and transmission of noise.
When the top of the oil storage tank is above the fuel unit and a gravity feed is not permitted, the suction
line should run to a point above the tank where an approved anti-siphon valve and a 5/8" OD gate valve
shall be installed inside. No ball check valve is required, but a union between the gate valve and the
strainer should be installed to facilitate removal of the strainer for occasional cleaning.
D. RETURN LINE
The return line should be the same size as a suction line and run as directly as possible from the return
opening in the fuel unit to the oil storage tank. The return line should extend into the oil storage tank to
the same depth as the suction line.
E. PRESSURE TEST FOR BURIED OIL LINES
It is important that buried oil lines be thoroughly tested for leaks before being covered.
F. MISCELLANEOUS INFORMATION
If suction and return lines are less than 30 feet in length, use at least 1/2" OD tubing. When the oil line is
30 feet or over, 5/8" OD tubing is recommended.
Where basement oil storage tanks or tanks installed above the burner are used, and/or when the oil flows
by gravity to the oil pump, a single-stage fuel unit with a single oil line to the pump may be used. Avoid as
many connections as possible in the suction line. Make all connections tight by using good pipe joint
compound for oil on all pipe threads. To minimize the possibility of air leaks, tighten packing gland on any
valve installed in the suction line. Also, be sure to tighten the oil filter cover, as filter gaskets often shrink.
Check for kinks in the oil lines as well as for possible air pockets and loose connections.
A water trap can be installed at the oil storage tank outlet to prevent water from entering the burner.
There are a number of fuel oil additives on the market that hold water in suspension and allow it to pass
through the burner. These additives can be added to the oil storage tank. Consult a local fuel oil dealer for
information concerning the use of these additives.
PART 12: PRIMING THE FUEL UNITS
DO NOT USE GASOLINE, CRANKCASE DRAININGS, OR ANY OIL CONTAINING GASOLINE.
A. SINGLE LINE SYSTEM
Locate the air bleed valve on the fuel unit (pump). Place a container underneath the air bleed valve. Open
the valve one quarter of a turn in the counter-clockwise direction. Turn the thermostat on the water heater
to a setting that is high enough to allow the burner to operate. Turn on the power supply to the burner.
Let at least one pint of oil flow into the container after the air is pumped out of the fuel unit. While running
under these conditions, the pressure valve in the pump will not open, and there will be no flame. Close
the air bleed valve after a pint of oil has flowed into the container. The burner should begin burning once
the air bleed valve is closed.