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HVACR215 – Mechanical for Oil
Oil Tanks
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Oil Tanks - General Notes
• All oil tanks must conform to local codes.
• These are mostly fire codes, administered by the
fire department.
• If no local codes exist use the national or
international codes or UL regulations.
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UL Label
• Stands for Underwriters Laboratory.
• The UL Label species where the tank can be
used:
– Inside
– Outside
– Underground
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UL Label
• The tank must be 12 gauge thickness for an
indoor tank.
• The tank must be a 10 gauge thickness for an
outdoor or underground tank.
• Outdoor or underground tanks must also have a
protective coating on them.
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Locations to install tanks
• Oil tanks may be installed in three possible
locations:
– Basement
– Outside
– Underground
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Indoor Tanks
• 275 or 330 gallon tanks
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They are low cost
Have a long life
Easy to pipe
Oil is maintained at a uniform temperature
Tank sizes are 22” Wide x 44” high x 78” long for flat
tanks or 26” wide x 42” high x 72” long for regular
tanks.
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Indoor Tanks
– Both of these tank sizes can be carried through a door.
– 330 Gallon tanks can be twinned together to create a
660 gallon tank that still falls within code of maximum
amount of oil storage.
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Indoor Tanks
• Location (in basement)
– Minimum of 5 feet to the burner
– Check all other local codes prior to installation.
• Height off the floor
– Determined by local code, but usually 10”
– Come with screw in floor flanges and can be mounted
to the floor.
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Indoor Tanks
• Tank must be on a noncombustible material.
• There must be a UL approved gauge installed
which indicates the amount of oil left in the tank.
• The fill line must have a cap to protect it from
water.
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Indoor Tanks
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Indoor Oil Tank
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Vent Line
• Must have a vent line to let air out as tank is filled.
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1 1/4” in MA
2” in CT
Must terminate with an approved weather cap.
Must be installed higher than fill line and pitch towards
the tank.
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Indoor Tanks
• Tank outlet must have a fire valve on it, usually a
Firematic valve that melts at 165 degrees.
• The outlet flange on older style tanks is a 1/2”
pipe from bottom of tank. This prevents water and
sludge to build up and tank eventually needs
cleaning.
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Indoor Tanks
• The outlet on newer style tanks is a 1/2” pipe
which is on one side of the tank near the bottom.
The tank is pitched 1” towards the valve and this
prevents buildup of sludge and condensation.
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Indoor Tanks
• The filter, usually a cartridge filter, is installed on
the outlet of the tank, after the valve.
• The filter must be changed with annual service.
• Install a second firematic valve near the burner to
maintain oil line prime.
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Indoor Tanks
• Oil supply line should have an oil safety valve
(OSV) installed.
• Supply lines can no longer run under the floor and
they must have a plastic or rubber case.
• Copper corrodes when it is contact with cement.
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Indoor Tanks
• If tank legs are longer than 16” they must have
supports.
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Tank Piping
• A six inch loop at both the burner and the tank is
required for flexibility.
• Return line (if a two pipe system) must be six
inches off the bottom of tank.
• Supply line (if not from side) must be three inches
from bottom of tank.
Tank Piping – 1 pipe system
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Tank Piping – 2 pipe system
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Tank Piping - Fittings
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Oil Safety Valve
• The oil safety valve is a device that acts to stop oil
flow in the event of a leak in the suction line.
• When the pump operates a vacuum is created in
the line opening the valve allowing oil to flow.
• Pump not operating? No flow of oil.
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Oil Safety Valve
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Outdoor Tanks
• Mainly used if there is no basement, also used in
mobile homes.
• Must be mounted on a masonry foundation for
stability.
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Outdoor Tanks
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Outdoor Oil Tanks
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Outdoor Tanks
• Come with some operational problems:
– Cold Climates prevent oil from flowing easily and also
allow condensation to build up in the tanks.
– May need to have the oil filter installed inside near the
burner rather than outside.
– May need to use a nozzle line heater
– May need to raise the pump pressure.
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Underground Tanks
• Not legal in most areas.
• They are installed on a concrete slab under
ground
• Outlet end must be pitched about 3” for every
1000 gallons.
• Must follow manufactures directions for
installation.
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Underground Oil Tank
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Underground Tanks
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Underground Tank
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Fill must be 2”
Vent must be 2” or greater, check local codes
Fittings must be black malleable iron, no cast iron.
Swing joints must be installed at every
underground elbow.
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Underground Tanks
• Fill and vent pipes must be from 3-5 feet from
nearest building opening.
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A redneck oil tank
DON’T DO THIS!!
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