Daikin IM 972-1 41
Controls and Operation
5 Control checks each pressure switch for closure.
6 If each pressure switch is closed, the control starts a 30
second prepurge and energizes W2. If either switch is
still open, the inducers will continue to be energized until
closure.
7 After prepurge time-out, control energizes W1 and
continues to energize W2, initiates spark for 2 seconds
minimum, 7 second maximum ignition trial, and initiates
120 second stage warm up timing.
8 Control detects flame, de-energizes spark and starts a 45
second indoor blower delay on timing.
9 After a fixed 45 seconds indoor blower delay on, the
control energizes the indoor blower.
10 After a fixed 120 seconds second stage warm-up period
control checks the thermostat input. If W1 and W2 are
present, control enters normal operating loop where all
inputs are continuously checked.
First Stage and Second Stage Removed Simultaneously:
1 Upon a loss of W1 and W2 the gas valve is de-energized.
2 2 Upon a loss of flame, each inducer will complete a 5
second post-purge and the indoor blower will complete a
90 second delay off.
3 Control in the stand by mode with solid red LED.
The integrated control is a three ignition system.
After a total of three cycles without sensing main burner
flame, the system goes into a 100% lockout mode. After one
hour, the ignition control repeats the prepurge and ignition
cycles for 3 tries and then goes into 100% lockout mode again.
It continues this sequence of cycles and lockout each hour until
ignition is successful or power is interrupted. During the
lockout mode, neither the ignitor or gas valve will be
energized until the system is reset by turning the thermostat to
the “OFF” position or interrupting the electrical power to the
unit for 3 seconds or longer.
The circulating air blower will start and run on the heating
speed if the thermostat fan switch is in the “ON” position.
The integrated furnace control is equipped with diagnostic
LED. The LED is lit continuously when there is power to the
control, with or without a call for heat. If the LED is not lit,
there is either no power to the control or there is an internal
component failure within the control, and the control should be
replaced.
If the control detects the following failures, the LED will flash
on for approximately 1/4 second, then off for 3/4 second for
designated failure detections.
1 Flash: Failed to detect flame within the four tries for
ignition.
2 Flash: Pressure switch or induced draft blower problem
detected.
3 Flash: High limit or auxiliary limit open.
4 Flash: Flame sensed and gas valve not energized or
flame sensed with no “W” signal.
5 Flash: Overtemperature switch open.
Operating Instructions
This unit is equipped with integrated furnace control. This
device lights the main burners each time the room thermostat
(closes) calls for heat. See operating instructions on the back
of the furnace/controls access panel.
DANGER
Never test for gas leaks with an open flame. It can cause an
explosion or fire resulting in property damage, personal injury
or death. Use a commercially available soap solution made
specifically for the detection of leaks to check all connections
as specified in the Mechanical Installation section of these
instructions.
DANGER
The spark ignitor and ignition lead from the ignition control are
high voltage. Keep hands or tools away to prevent electrical
shock. Shut off electrical power before servicing any of the
controls. Failure to adhere to this warning can result in
personal injury or death.
DANGER
Should overheating occur or the gas supply fail to shut off,
shut off the manual gas valve to the unit before shutting off
the electrical supply. Failure to do so can result in an
explosion or fire causing property damage, severe personal
injury or death!
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