SERVICING
41
3. Remove the pressure control hose from the control
and interconnect with a digital manometer as shown:
Reconnect wires to the Common and NO terminals.
With Power ON:
WARNING
Line voltage now present
4. Energize furnace for heating cycle. The induced
draft blower motor will begin to run. The manometer
should read approximately -1.2” ± 0.3” W.C with no
combustion.
5. Remove and check the two electrical wires and using
the VOM check from Common to NO (Normally
Open), it should read closed (with I.D. motor
running). If not as above, replace pressure control.
6. Reconnect all wires to the control and place in
heating cycle.
7.
As the unit fires on high stage, the manometer
negative pressure will drop to -1.0” ± 0.3” W.C.
8. If not as listed, replace control.
NOTE: The pressure switch must be mounted with the
diaphragm in a vertical position.
High Altitude Application
High Altitude Derate - U.S. Installations Only
IMPORTANT NOTE: The gas/electric units naturally
derate with altitude. Do not attempt to increase the
firing rate by changing orifices or increasing the
manifold pressure. This can cause poor combustion
and equipment failure. At all altitudes, the manifold
pressure must be within 0.3 inches W.C. of that listed
on the nameplate for the fuel used. At all altitudes
and with either fuel, the air temperature rise must be
within the range listed on the unit nameplate. Refer
to the Installation Manual provided with the LP kit for
conversion from natural gas to propane gas and for
altitude adjustments.
When this package unit is installed at high altitude, the
appropriate High Altitude orifice kit must be installed.
As altitude increases, there is a natural reduction in the
density of both the gas fuel and combustion air. This kit
will provide the proper design certified input rate within the
specified altitude range. High altitude kits are not approved
for use in Canada. For installations above 2,000 feet, use
kit HA-03. The HA-03 kit is used for both Natural and LP
gas at high altitudes.
NOTE: Up to 2,000 feet, no changes are required;
above 2,000 feet, refer to the gas/electric package unit
specification sheets for required kit(s).
Use LPM-08 (2 stage heat models) propane conversion
kit for propane conversions at altitudes below 2000 feet.
Natural gas installations below 2000 feet do not require a
kit.
For propane conversions above 2000 feet, high altitude kit
HA-03 is required in addtion to the propane conversion kit.
Testing Ignition Control Module
NOTE: Failure to earth ground the unit, or a high
resistance connection in the ground may cause the
control to lockout due to failure to flame sense.
WARNING
To avoid personal injury or death due to electric shock,
wiring to the unit must be properly grounded. Disconnect
power before installing or servicing.
