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Integral Indirect Gas-Fired Heat Module
OPTION
6.3.1 Enable the Unit Controller
Go to Home Screen > Main Menu > Unit Enable. Switch Unit Enable to ON. Exit this menu item
by pressing the ESCAPE button.
When the Unit Status is changed to ON, the dampers will open, the fans will begin running and
a call for heat will go from the controller to the gas heat module.
As soon as the controller is enabled, the gas heat module will immediately begin a 15 second
pre-ignition purge, followed by ignition. When gas furnaces are lit for the first time, there is
often air in the gas line that will prevent gas from reaching the burners. When this happens,
the heat module will not ignite and the module controller will try three times to light. After three
tries, the heat module controller will go into lockout.
After the purge cycle, the heat module will switch on the gas valves and the igniter, producing
gas pressure at the manifold.
Verify that the gas pressure at each pressure tap on the gas manifold is between 3.4 InWC and
3.5 InWC for natural gas or 10.0 InWC for LP gas at maximum input.
Record the gas pressures in the chart below.
When the heat module is lit, view the flames at each burner in accordance with the instructions
in Section 6.6.1 of this manual. Adjust high fire and low fire, if necessary.
OBSERVED INLET GAS PRESSURE
(must be between 5.0 InWC and 13.5 InWC for Natural
Gas and between 11.0 InWC and 13.5 InWC for LP Gas)
OBSERVED MANIFOLD GAS PRESSURE AT HIGH FIRE
(must be between 3.4 InWC and 3.5 InWC
for Natural Gas and 10.0 InWC for LP Gas)
Single Manifold Pressure
(if applicable)
Split Manifold Pressure
Left Side
Split Manifold Pressure
Right Side
(SPECIFY TYPE OF GAS AND PRESSURE OBSERVED))
6.4 FAILURE TO IGNITE
On the initial start-up, or after the unit has been off for long periods of time, the first ignition
trial may be unsuccessful due to need to purge air from the manifold at start-up.
If ignition does not occur on the first trial, the gas and spark are shut off by the ignition control
and the control then enters an inter-purge period of 15 to 90 seconds, during which time the
draft inducer continues to run. At the end of the inter-purge period, another trial for ignition will
be initiated.
Control will initiate up to three ignition trials on a call for heat before lockout of control occurs.
Control can be brought out of lockout by turning the controller setpoint to its lowest position
and waiting 5 seconds and then turning it back up to call for heat. Some controls provided will
automatically reset after one hour and initiate a call for heat.
6.5 TEMPERATURE RISE
Testing for heat rise is done as part of unit commissioning. It should not be attempted at this
time because the gas heat module must run at full output and the fans must be running at
maximum output.
Restore controller settings and shut off gas at the supply valve. Remove manometer and
reinstall plugs in the pressure taps.
OPERATION
