American Standard 50A65-475 Manual page 41

Diagnosing the V/S Vent Motor/Manual Method
4. Jumper pin #4 to pin #3 (B common)
Does the vent motor start and go through the
learning curve?
YES: Go to Step #5.
NO: Remove the orange wire from the LPS
pressure switch and repeat Step #4.
If the motor still fails to start, replace
the motor. Don't forget to replace the
orange lead. If the motor starts, this
may indicate that the LPS pressure
switch is stuck closed. Check and
replace, if necessary.
5. After the LPS pressure switch has closed, opened,
and closed (learning curve), quickly remove one
end of the jumper from pin #4 and move it to pin
#5, keeping the other end of the jumper on pin #3
(B common). The motor must remain spinning.
If it stops, repeat Step #4 and Step #5.
Does the motor go on high speed?
YES: Replace the White-Rodgers IFC board.
NO: Before replacing the motor, remove the
brown wire from the HPS pressure
switch and repeat the test in Steps #4
and #5. If it still does not go to high
speed, replace the motor. Don't forget
to replace the brown lead. If the motor
starts, this may indicate that the HPS
pressure switch is stuck closed. Check
and replace, if necessary.
4
1
2
3
4
5
5
1
2
3
4
5
1
2
3
4
5
Both Tests 4 and 5 may use another connection which
may be easier to reach.
The pin #3 signal (B common) is also found on B
at the LVTB.
39
LVTB
B