IF:
a. Both LEDs are on continuously:
System phasing is okay.
b. One or both LEDs are rapidly flashing:
(1.) Line voltage polarity is reversed
(2.) Reverse SEC-1 and SEC-2 in furnace with rapid flashing LED.
c. One LED is off, 1 LED is on continuously:
(1.) The 24-vac circuit is inoperative on furnace with LED light off.
(2.) Check transformers, auxiliary limits, and door switches in both furnaces and correct problem.
Fig. 13—Single Stage Furnace and A/C-Single Stage Thermostat
A02227
THERMOSTAT
MAIN ( LH ) FURNACE
RELAY 1
PLC
ALS-M
PLA
NOTE #5
Y/Y2
G
W
R
C
OM
Y1
BLK
WHT
TEST/TWIN
TKR
BLU
SEC-2
SEC-1
TRAN
WHT
BLK
L2
NOTE #2
PR1
BLK
WHT
RED
YEL
PLB
SECONDARY ( RH ) FURNACE
Y/Y2
G
W
R
C
OM
Y1
TEST/TWIN
BLU
SEC-2
SEC-1
BLK
WHT
RED
YEL
PLB
RED
TRAN
WHT
BLK
L2
NOTE #2
PR1
MAKE NO THERMOSTAT
CONNECTIONS TO
SECONDARY OR RH
FURNACE
1
2
ORN
BLU
RED
EXTENSION HARNESS
(IF USED)
PLA
1
2
ORN
BLU
ILK-1
ALS-S
NOTE #1
ORN
NOTE #3
24 VAC
TRANSFORMER (FIELD SUPPLIED) NOTE #4
115 VAC
C
Y
OUTDOOR UNIT
NO. 1
C
Y
OUTDOOR UNIT
NO. 2
LEGEND:
NOTES:
Y
G
W
R
C
OM
NOTE #3
NOTE #6
327893-101 REV. A
1.
ALS-S and ILK-1 are located in the SECONDARY or RH furnace
blower compartment.
2.
Primary connections of transformer not shown; refer to furnace
wire label.
3.
When extension harness is not required PLA and PLB must be
routed through holes in casings.
4.
Transformer = 115 VAC primary / 24 VAC secondary / 40VA.
5.
Relays = 24 VAC coils / pilot duty / normally open.
6.
Y1 and DHUM terminal not available on "RED" LED control board.
NOTE #6
ALS-M
MAIN AUX. LIMIT SW., OVERTEMP-MANUAL
RESET, SPST - (N.C.)
ALS-S
SECONDARY AUX. LIMIT SW.,
OVERTEMP-MANUAL RESET, SPST - (N.C.)
ILK-1
SECONDARY AUX. BLOWER DOOR
INTERLOCK SWITCH, SPST - (N.O.)
PLA
2-CIRCUIT TWINNING KIT CONNECTOR
PLB
4 - CIRCUIT TWINNING KIT CONNECTOR
PLC
1 - CIRCUIT TWINNING KIT IN-LINE SPLICE
TEST/TWIN COMPONENT TEST & TWINNING TERMINAL
TKR
TWINNING KIT RELAY, SPST - (N.O.)
TRAN
TRANSFORMER - 115VAC / 24VAC
(PART OF FURNACE)
115 VOLT WIRING
TWINNING KIT EXTENSION HARNESS (REQUIRED)
FIELD WIRING
FACTORY WIRING (TWINNING KIT)
FIELD INSTALLED AIR CONDITIONING WIRING (WHEN REQUIRED)
SINGLE STAGE FURNACE & A/C-SINGLE STAGE THERMOSTAT
D
HUM
D
HUM
4
1
3
2
4
1
3
2
FIELD
SUPPLIED
RELAY
—18—
