User guide

Two Times Air proving switch contacts do not close during a call for heat.
Are
air-proving switch
contacts stuck open?
(Perform continuity
check.)
Does
fan motor start up
for prepurge
during initial call
for heat?
Is
fan wheel
binding?
Is fan wheel
loose on motor
shaft?
Yes
Yes
Yes
No
Check for binding of air-proving switch arm on housing, air-proving flapper stuck, or out of adjustment. Repair or replace as necessary.
Yes
Yes
Check for proper clearance of fan wheel to motor mount. If good, replace fan wheel, or check for housing alignment.
Tighten set screw(s) on fan. Make sure set screw(s) are tightened against flat(s) of motor shaft.
Yes
Clean the fan wheel with compressed air or soft brush.
Defective motor or capacitor. Replace motor.
Yes
Remove obstruction. Clean as necessary.
No
Is fan wheel
plugged with
dirt?
No
Is there
an obstruction
in blower outlet
preventing air-proving
switch closure?
Is
proper voltage
supplied to motor
from ignition
module?
No
If improper voltage is supplied,
contact electrician.
- OR -
If no voltage is supplied to
motor, check wiring, and
connections. If good, replace
ignition control module.
No
Yes
Is
proper
voltage being
sent to air-proving
switch?
Check for 24 volts from
ignition control terminal PS1
to air proving switch. If absent.
check all electrical wiring. If
wiring is good, but 24 volts is
absent, replace ignition
control.
No
23
With motor in operation, check for 24 volts from terminal PS1 and at terminal PS2 at the control module. If 24 volts is sent from PSI, but not received from the air provng switch at PS2, replace the air proving switch.
No
No