Service Manual

SYSTEM OPERATION
23
L2
INDUCER
LOW
HIGH
L1
ODF
LOW
HIGH
T1
Q3
K4
K3 K5
K6
T2
K7
FS
U1
U2
U6
U7
U4
U5
U3
P2
K2
K1
ECON
STAGE
DELAY
C9
SPEED UP
SW1
FAULT
RECALL
BLOWER
OFF
DELAY
F1
R C W1W2 G Y2
90
120
150
180
10MIN
5 MIN
NONE
PARK
1
2
3
4
5
Y1
PCBAG127 Control Board
DESCRIPTION
The ignition control is designed for use in gas heating/electric
cooling package equipment (rooftop applications) and oper-
ates with a two stage heat and two stage cooling system. It
is a direct spark ignition system that uses a 22,000 volt spark
to ignite the burners. A flame sensor is used to monitor the
flame.
The board has the option of using a single or two stage
thermostat. The board also controls the indoor blower and
has an adjustable heat fan off delay.
There is also a fault recall button for recalling the last 5 fault
codes. To recall the fault codes, depress the fault recall
button for at least 2 seconds but not more than 4 seconds.
To clear the fault code memory, depress the fault recall
button for at least 5 seconds.
The following tables list the functions for the connectors and
terminals, the timings, and the fault codes for the PCBAG127
control board.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.