Two- Stage Multi Position Furnace
Service
Manual
43
440 08 2002 02
SV9541Q ELECTRICAL VARIATION
2 --STAGE Con’t
Connector (Pin #) Description Voltage Signal When Signal is Present
C1 (pin 4) Data Line Non--periodic
1
/2
wave
rectified AC
Present when the door interlock switch is closed. Same
signal as P1 (pin 5).
C1 (pin 5) Limit Supply
1
/2
wave rectified AC Present when the 24 VAC transformer is powered.
C1 (pin 6) C (xfmr common) 0VAC Always present
C1 (pin 7) R 24 VAC Present when the door interlock switch is closed.
C1 (pin 8) 24 VAC 24 VAC Present when the door interlock switch is closed.
C2 (pin 1) HSI return 24 VAC (with igniter present) Present when HSI is not turned on. When HSI is on, this
signal is 0 VAC to 10 VAC depending on input line volt-
age potential.
C2 (pin 2) HSI supply 24 VAC Present when the door interlock switch is closed.
C2 (pin 3) Not connected 0VAC Not connected
C2 (pin 4) Flame sense >80 VAC Present when the door interlock switch is closed.
C3 (pin 1) Inducer supply 115 VAC Present when the inducer draft blower motor is on (Heat
modes, Open Limit mode).
C3 (pin 2) L1 115 VAC Present when the door interlock switch is closed.
C3 (pin 3) Inducer return 0VAC Always present (neutral connection).
C3 (pin 4) L2 (neutral) 0VAC Always present
* With a motor tap connected, voltage appears at “unpowered” fan termi-
nals whenever the motor is running due to feedback through the motor wind-
ings.
** Voltage appears on the “unpowered” inducer terminal whenever the in-
ducer motor is running due to feedback through the motor windings.
NOTE1: Using a Fluke 79 digital Multi--Meter (DMM),
1
/2
wave rectified AC
voltage typically measures about 14 VAC. The Fluke 79 is not a “true” RMS
meter .
To Next Page
Loading...
