Unit installation

247585-UAI-A-0706
Unitary Products Group 3
TESTS AND ADJUSTMENTS
TESTS AND ADJUSTMENTSTESTS AND ADJUSTMENTS
TESTS AND ADJUSTMENTS
GAS ORIFICE CONVERSION FOR PROPANE (LP)
GAS ORIFICE CONVERSION FOR PROPANE (LP)GAS ORIFICE CONVERSION FOR PROPANE (LP)
GAS ORIFICE CONVERSION FOR PROPANE (LP)
This furnace is constructed at the factory for natural gas-fired
operation, but may be converted to operate on propane (LP)
gas by using a factory-supplied LP conversion kit. Follow
these instructions when converting the furnace.
IMPORTANT - The inlet gas pressure operating range table
specifies what the minimum and maximum gas line pressures
must be for the furnace to operate safely.
The gas line pressure MUST BE
11” W.C. (2.74 kPA) for Propane (LP) Gas
in order to obtain the BTU input specified on the rating plate
and/or the nominal manifold pressure specified in these
instructions and on the rating plate.
ADJUSTMENT OF MANIFOLD GAS PRESSURE
ADJUSTMENT OF MANIFOLD GAS PRESSUREADJUSTMENT OF MANIFOLD GAS PRESSURE
ADJUSTMENT OF MANIFOLD GAS PRESSURE
FOR 90% FURNACES
FOR 90% FURNACESFOR 90% FURNACES
FOR 90% FURNACES
Manifold gas pressure may be measured by two different pro-
cedures. It may be measured with the burner box cover in
place or it may be measured with the burner box cover
removed. Follow the appropriate section in the instructions
below. Refer to Figure 1 or 2 for a drawing of the locations of
the pressure ports on the gas valve.
Turn gas off at the ball valve or gas cock on gas supply
line before the gas valve. Find the pressure ports on the
gas valve marked OUT P and IN P.
1. The manifold pressure must be taken at the port marked
OUT P.
2. The inlet gas line pressure must be taken at the port
marked IN P.
3. Using a 3/32” (2.4 mm) Allen wrench, loosen the set-
screw by turning it 1 turn counter clockwise. DO NOT
REMOVE THE SET SCREW FROM THE PRESSURE
PORT.
Read the inlet gas pressure using either of the two
methods below.
Reading the gas pressure with the burner box cover in place:
1. Disconnect the pressure reference hose from the right
side of the burner box. Using a tee fitting and a short
piece of hose, connect the negative side of the manome-
ter to the burner box as described below.
2. Remove one end the 5/16” (7.94 mm) ID flexible tubing
over the pressure port on the burner box.
3. Insert the end of the 5/16” (7.94 mm) tubing, that has the
1/8” (3.175 mm) adapter at the end of the tube, in to the
1/8” (3.175 mm) tee.
4. Connect the 1/8” (3.175 mm) tee to the burner box
adapter and to the negative side of a U-tube manometer
or digital pressure measuring equipment with 2 1/8”
(3.175 mm) tubes.
5. Use the 5/16” (7.94 mm x 1/8” (3.175 mm) reducing cou-
pling and a 4” (101.6 mm) piece of 1/8” (3.175 mm) tub-
ing to connect the positive side of the manometer to the
gas valve pressure reference port. Refer to Figures 3
and 4 for connection details.
Reading the gas pressure with the burner box cover
removed - Remove the screws securing the burner box front
cover plate. Remove the cover. The gasket and may stick in
place. Connect the positive side of the manometer to the gas
valve as described in E above. There will be no second con-
nection to the manometer, as it will reference atmospheric
pressure. Refer to Figures 3 and 4 for connection details.
IMPORTANT - The cap for the pressure regulator must be
removed entirely to gain access to the adjustment screw.
Loosening or tightening the cap does not adjust the flow of
gas.
PROPANE AND HIGH ALTITUDE CONVERSION KITS
It is very important to choose the correct kit and/or gas orifices for the altitude and the type of gas for which the furnace
is being installed.
Only use natural gas in furnaces designed for natural gas. Only use propane (LP) gas for furnaces that have been
properly converted to use propane (LP) gas. Do not use this furnace with butane gas.
Incorrect gas orifices or a furnace that has been improperly converted will create an extremely dangerous condition
resulting in premature heat exchanger failure, excessive sooting, high levels of carbon monoxide, personal injury,
property damage, a fire hazard and/or death.
High altitude and propane (LP) conversions are required in order for the appliance to satisfactory meet the application.
An authorized distributor or dealer must make all gas conversions.
In Canada, a certified conversion station or other qualified agency, using factory specified and/or approved parts, must
perform the conversion.
The installer must take every precaution to insure that the furnace has been converted to the proper gas orifice size
when the furnace is installed. Do not attempt to drill out any orifices to obtain the proper orifice size. Drilling out a gas
orifice will cause misalignment of the burner flames, causing premature heat exchanger burnout, high levels of carbon
monoxide, excessive sooting, a fire hazard, personal injury, property damage and/or death.