Sterling QVOF User Manual

INSTALLATION INSTRUCTIONS & PARTS LIST

OIL FIRED UNIT HEATERS

MODELS: QVOF (50, 84, 100, 140, 180, 250)

ATTENTION: READ THIS MANUAL AND ALL LABELS ATTACHED TO THE UNIT CAREFULLY BEFORE
ATTEMPTING TO INSTALL, OPERATE OR SERVICE THESE UNITS! CHECK UNIT DATA PLATE FOR ELECTRICAL
SPECIFICATIONS AND MAKE CERTAIN THAT THESE AGREE WITH THOSE AT POINT OF INSTALLATION. RECORD
THE UNIT MODEL AND SERIAL No.(s) IN THE SPACE PROVIDED. RETAIN FOR FUTURE REFERENCE.

IIOF-1

Model No.

Serial No.

FOR YOUR SAFETY

The use and storage of gasoline or other flammable vapors and liquids in open containers in
the vicinity of this appliance is hazardous.

WARNING: Improper installation, adjustment, alteration, service or maintenance can
cause property damage, injury or death. Read the installation, operating and
maintenance instructions thoroughly before installing or servicing this equipment.

WARNING: Install, operate and maintain unit in accordance with manufacturer's
instructions to avoid exposure to fuel substances or substances from incomplete
combustion which can cause death or serious illness. The state of California has
determined that these substances may cause cancer, birth defects, or other
reproductive harm.

INSTALLER'S RESPONSIBILITY

Installer Please Note: This equipment has been test fired and inspected. It has been

shipped free from defects from our factory. However, during shipment and installation,
problems such as loose wires, leaks or loose fasteners may occur. It is the installer's

responsibility to inspect and correct any problems that may be found.

RECEIVING INSTRUCTIONS

Inspect shipment immediately when received to determine if any damage has occurred to the
unit during shipment. After the unit has been uncrated, check for any visible damage to the
unit. If any damage is found, the consignee should sign the bill of lading indicating such
damage and immediately file claim for damage with the transportation company.

HVAC EQUIPMENT

260 NORTH ELM STREET/WESTFIELD, MA 01085

TEL: [phone] FAX: [phone]

Sterling oil powered Unit Heaters are shipped in a heavy
duty reinforced corrugated shipping crate. Upon receiving
your unit, a careful inspection of this crate should be
made to ascertain if there is any damage either external
or concealed.

The thermostat should be mounted away from the blower
air stream on an inside wall or partition approximately 5
feet above the floor.

3 – FUEL OIL PIPING

All Unit Heaters come completely assembled and wired.

GENERAL INFORMATION

Oil Fired Unit heaters are designed to be suspended.
However, they can be installed on approved fire-resistive
slabs or supports having no combustible material against
the underside of the unit. Other clearances to
combustible sources should be not less than 6″ from
sides and top and 18″ from flue pipe in any direction.
When suspending the unit from a ceiling, an allowance
of 18″ from the top of the unit should be made to
accommodate a barometric draft regulator.

Unit Heaters should not be subjected to negative
pressures (drafts) created by room or building exhaust
fans. Sufficient air for combustion is an important
consideration.

Special attention must be given to those installations,
such as service stations and warehouses, where the
units have short stacks since the draft may not be
adequate.

When the vertical distance from the fuel supply tanks to
the fuel unit on the burner is more than 15 feet, or
when a multiple installation is required, the fuel system
should include a boost pump. See Figure 2.

INSTALLATION PROCEDURE

1 – HANGING OF UNIT

Welded to the top of the heat exchanger at each corner
is a 3/4″ pipe coupling which will accommodate a
standard 3/4″ pipe nipple. There are many ways the
suspension of a unit can be accomplished. However,
care should be taken to be sure the supporting beams
or girders are of ample strength to support the weight
of the unit. It is good practice to distribute the weight
over several girders rather than depending on one.

2 – WIRING

As this is a prewired unit, all controls, with the exception
of the thermostat are mounted and wired. 115 volt
service to utility box on unit heater is required. Unit
should be fused independent of other fixtures,
equipment, etc. There is a service switch on the unit.
An additional switch should be provided at the room or
building entrance.

a) Gravity Systems

Gravity systems where fuel supply is on the same level
as unit, require one line from tank to burner. This should
be 1/2″ or 3/8″ O.D. tubing or 3/8″ iron pipe according
to local codes. There should be a hard seat globe valve
at tank. A Main line oil filter should be installed
immediately after valve. Another valve, either hard seat
globe or heat responsive, should be installed at burner.
Local codes must be adhered to.

b) Lift Systems

Lift systems where fuel supply tank is below unit, require
a two-pipe system. See Figure 1.

Suction and return lines should originate no less than
2″ nor more than 4″ from bottom of fuel tank. If code
permits, 1/2″ O.D. soft tubing should be used. A double­tapped bushing should be used in tapping of tank with
a slip connector so that both lines are continuous from
bottom of tank to inside of building.

A good quality ball check valve should be in the suction
line immediately inside of building.

Care should be exercised in installing lines in tank so
that they do not curl up inside of tank.

Lines should continue to burner either as copper tubing
or black pipe, depending on local codes, and should be
run straight and direct, eliminating need for bends or
elbows as much as possible. Lines should be securely
fastened to eliminate vibration and/or sagging.

Be sure bypass plug is installed in proper place, tightly
secured. See instruction sheet attached to pump for
more detail. On all connections, use oil resistant joint
compound. Either hard seat globe valve or heat
responsive valve (Firomatic or equal), depending on
code, should be installed in suction line as close to
pump as practicable.

A boost pump should be used on multiple unit heater
installations, or where an installation has more than a
15 foot lift (measured from the suction line in fuel tank
to the fuel unit on the burner). See Figure 2

2

Figure 1 - Fuel Oil Piping.

Figure 3

VALVE

FILTER

GROUND LEVEL

CHECK VALVE
(ENLARGED)

BURNED

FUEL OIL

TANK

Figure 2 - Piping Overhead System

VACUUM BREAKER

35 FT. MAX.

PRESSURE HEAD

(OPTIONAL)

15 FT. MAX.

SUCTION LIFT

VALVE

LINE PRESSURE
NOT TO EXCEED 6 PSI

2 – 4 FT.

FURNACE

FURNACE

NO. 1

NO. 2

1/2" O.D. COPPER TUBING

SUPPLY LINE

COMPOUND

GAUGE

VALVE

PUMP

FILTER

RETURN LINE

FURNACE

NO. 3

WALL

CHECK VALVE

INLET

LINE

RETURN LINE

SUCTION AND
RETURN LINE
CLEARANCE FROM
BOTTOM OF TANK
MINIMUM 2"
MAXIMUM4"

1/2" O.D. COPPER TUBING

SUCTION AND RETURN
LINE CLEARANCE FROM
BOTTOM OF TANK

TANK

MINIMUM 2"
MAXIMUM 4"

TO ROOF

BAROMETRIC

DRAFT

REGULATOR

BAROMETRIC

DRAFT

REGULATOR

"Y"

45° L

90°

UNIT 1 UNIT 1

4 – FLUE CONNECTIONS

Connect flue pipe to chimney. If chimney is masonry
type, be sure base is clean of debris and that opening
through tile is at least as large as flue pipe (see
specification sheet).

Chimney, either masonry or pre-fab, should be in
accordance with local requirements. The flue gas exit
of a chimney shall be at least 3 feet above the highest
point where the chimney passes through the roof of a
building, and at least 2 feet higher than any portion of a
building within 10 feet of the chimney. Chimney should
not be connected to an open fireplace, but could serve
two heating units.

NOTE: When two units are connected to a common
chimney, they should be connected as shown in
Figure 3.

Barometric draft regulator should be installed in flue
pipe, Regulator should be installed in run of flue pipe,
either horizontal or vertical. It is poor practice to install
in a tee that is substituted for an elbow as this has a
tendency to puff odors out of regulator on starts.

Special attention must be given to those installations
such as service stations and warehouses where units
are suspended at ceiling level. Because of the height
restrictions on the chimney, draft is not adequate.
Available for these installations is a draft inducer and
prover at additional cost.

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