10757-UAI-B-1204
2
Unitary Products Group
GENERAL
This accessory provides the parts to operate a natural gas
furnace at elevations between 2,000 and 6,000 feet (610 and
1829 meters). Conversion is CSA certified for 2,000 to 4,500
feet only.
This instruction covers the conversion only. The Installation
Instruction supplied with the unit is to be used for all other
aspects of the installation.
FURNACE CONVERSION
1.
Remove the access panel to the gas heat compartment.
2.
Disconnect the ignitor and sensor cables from each of
the two ignition control modules.
3.
Disconnect the wiring from both gas valves.
4.
Remove the screws holding the complete manifold/
burner assembly to the unit.
5.
Carefully remove the complete manifold/burner assem-
bly from the unit.
6.
Remove the screws holding the right side support to the
front burner support. Carefully move both manifolds
away from the front burner support until the main burner
orifices can be removed.
7.
Disconnect the pilot tubing at both pilots. Remove the
existing gas pilot orifices and discard them.
8.
Remove the existing burner orifices from the manifolds
and discard them.
9.
Refer to the Orifice Label (035-07981) on the outside of
the blower access panel to verify that the proper size
burner and pilot orifices from this accessory are installed
with the respective heating section.
10. Coat the threads of the new burner orifices from this kit
with pipe compound that is resistant to the action of pro-
pane gases. Use compound sparingly, making sure that
excess compound does not plug the orifices. Install the
orifices in the manifolds, and tighten them. After install-
ing an orifice in each location, discard any left over ori-
fices.
11. Install the appropriate gas pilot orifices from this kit.
Reconnect and tighten the pilot tubing at the pilots.
12. Replace the assembly into the unit. Make sure that the
burners are properly aligned.
13. Re-connect the ignitor, sensor cables and wiring to the
gas valves to the same location as were disconnected in
Step 2 and 3, or refer to the unit wiring diagram.
14. Mark the appropriate data ( burner orifice size, manifold
pressure and heat exchanger input capacity) on the
conversion labels provided and install them adjacent to
the unit data plate.
15. Refer to the Gas Heat section of the unit installation
instructions for proper installation and start-up proce-
dures
TESTS AND ADJUSTMENTS
All adjustments and testing must be performed at the time of
conversion. Since the units contain a two-stage heating sys-
tem, each system requires testing per the following proce-
dures.
1.
Connect a manometer to the pressure tap in the mani-
fold. Connect a power supply and a natural gas supply to
the unit, if not already connected.
2.
Turn on the natural gas supply. Bleed air from the gas
supply lines at a point as close to the inlet of the gas
valve as is practical. Turn gas valve knob or switch, to
the “ON” position.
3.
Connect a jumper between terminals “R” and “W” on the
circuit board to simulate a call for heat.
4.
Make sure unit electrical disconnect switch is in the OFF
position, then energize the power supply to the discon-
nect switch.
5.
Turn unit electrical disconnect switch ON. The combus-
tion blower should start and the pilot electrode should
start sparking.
6.
After air has been purged from the pilot supply line, pilot
ignition should occur. Shortly after pilot ignition, the main
gas valve will open as indicated by the manometer. Main
burner ignition may be delayed on the first ignition cycle
due to air in the gas manifold.
7.
Observe several ignition cycles. The pilot burner and all
main burners must ignite without delayed ignition or
burning at the orifices. If delayed ignition is observed,
verify that pilot flame is adjusted correctly (refer to Pilot
Flame Adjustment section of the unit Installation Instruc-
tion), and that the pilot is properly mounted (not loose or
Improper installation, adjustment, service, or main-
tenance can cause injury or property damage;
therefore, only a qualified installer or qualified ser-
vice personnel should perform this conversion.
If the furnace is connected to gas and power sup-
plies, ensure both are shut off before proceeding.
