2. C is used to connect the brown wire of the thermostat to
provide a return path to ground through the fuse which
protects the transformer. C is fused on the HK61GA001
board.
3. G is used to control the switching of the relay to turn the fan
on through the normally open contact of the relay.
4. Y on the HK61GA001 is used as the junction for the
outdoor section’s Y connection which controls the compres-
sor contactor for heat pump and cooling modes. The
HK61GA003 board contains a 90-sec fan-off delay which
begins timing when the Y is de-energized.
5. O is used as a junction for a heat pump reversing valve
circuit.
Fig. 7—HK61GA003 Printed-Circuit Board
A97026
3
6
9
12
2
5
8
11
1
4
7
10
LOW VOLTAGE
TERMINAL BOARD
2ND STAGE
3RD STAGE
FUSE
(LOW VOLTAGE)
CONNECTIONS
FOR VARIOUS
ACCESSORIES
FAN CONNECTIONS
ELECTRIC HEAT
BREAKOFF TABS
FOR STAGING
HK61GA003
PLUG
TRANSFORMER
CONNECTIONS
ELECTRONIC AIR
CLEANER CONNECTIONS
FAN INTERLOCK
DIODES AND FAN
TIME DELAY OFF
CIRCUIT
AUX1
W3
L
W2
O
E
Y
G
R
C
AUX2
DUMMY
DUMMY
DUMMY
COMMON
COMMON
240 VAC
240 VAC
TRANSFORMER
AC LINE
FAN
RELAY
24VDC
FAN
EAC2
L2
T3
T2
T1
EAC1
L1
F4
F3
F2
F1
HK61GA003
Y
R
W2-3
5 AMP
FUSE
MAX
2FD-1
W2-E
—10—
