SYSTEM OPERATION
39
Horizontal Installations
Filter(s) must be installed external to the furnace casing for
horizontal installations. For most installations it is preferable
simple by merely removing the grille, rather than going into
the attic or crawl space.
external to the furnace casing, for installation of a permanent
over the indoor blower compartment area of either side panel,
return air ductwork.
The electronic air cleaner and media air cleaner are multi-
installed in any position, except with the access door facing
down. The best location for the air cleaner is in the return
air duct next to the blower compartment. Before installing
the air cleaner, consider the application. The electronic air
cleaner must be readily accessible for periodic inspection and
air cleaner must be readily accessible for periodic inspection
and replacement of the Media Air Cleaner (AMU and GMU)
operation. Carbon Filters 1156-3 and 1856-3 (set of 3) are
are available and can be seen at www.goodmanmfg.com.
POWER UP:
• When power is supplied, the control will energize the
Red LED, microcomputer runs its self-check routine.
• The control will check the status of the gas valve circuitry.
• Line polarity is checked.
• The control then enters standby waiting for a call for
heat or cool.
•
signaling standby mode
HEAT MODE:
Call For 1st Stage Heat
•
close signaling the control module.
• The microcomputer runs its self-check routine.
•
heat operation.
• The control module checks the high limit (and/or auxiliary
limit) switch(es) for normally closed contacts.
• The control checks the low pressure switch for a shorted
condition.
• The gas valve relay status is checked for proper
operation. Once the low pressure switch is detected
open, the inducer blower is energized at high speed and
• The low pressure switch is checked for closure.
• Once the low pressure switch is closed, the pre-purge
period begins. The inducer will be energized at high
speed for the pre-purge period.
• Following the completion of pre-purge, the inducer
switches to low speed and the igniter warm up period
begins.
• After completion of the igniter warm up period:
- Trial for ignition begins.
•
the conclusion of the ignition activation period (IAP),
•
begins timing.
•
is sensed:
- Control enters normal operating loop where all
inputs are continuously checked.
• After the delay to heat on period, the circulator fan is
energized at the low heat speed.
• The air cleaner will be energized with the circulator.
• If the call for heat is lost while the control is in the trial for
enters the post-purge routine. The post-purge time will
be increased to 60 seconds. After completing the post-
purge, the control resumes normal operation.
CALL FOR 2ND STAGE AFTER FIRST STAGE:
• The inducer motor is enabled at high speed.
• The pressure switches are checked for closure. Closure
of the second stage pressure switch will energize the
• The high speed circulator output is energized.
• A call for 2nd stage without a call for 1st stage
displayed on the LED. This error code will only be stored
in memory once during a single power cycle.
2ND STAGE SATISFIED, FIRST STAGE STILL
CALLED:
•
the inducer blower is reduced to low speed which de-
energizes the second stage of the gas valve.
•
reduced to low heat speed.
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