Service Manual

34
34
Service Procedure V:
Blower Testing and Replacement
Y
Does blower energize?
Ensure control display
shows “heating.” Raise
temperature setpoint if
necessary.
Is collector high limit
switch in normally closed
position?
Refer to ignition
module/control board
illustration. Is there
24VAC between blue
and yellow wires at
location J8.
Replace ignition
module/control board.
Is there 120VAC across
the white and black
wires at the incoming
power harness
connection? (see image
at right).
Determine
power source
problem and
correct.
Call Technical
Support.
Replace blower (see Blower
Replacement Procedure, pg 34).
Correct safety circuit
problem per safety
circuit trace (see
Blocked Vent Switch
Testing, pg 41).
Replace ignition
module/control
board.
Repair/replace wire
harness.
Replace blower (see
Blower Replacement
Procedure, pg 34).
Y
Y
Y
Y
Y
N
N
N
N
N
N
Y
Y
N
N
N
Y
120 VAC
power
connection
Black wire
leading to
blower
looped
through
amp probe
Is blower wheel
secured to blower
motor shaft?
Check amp draw
through BLACK wire
lead of blower motor. Is
there .6 to 3.0 amps?
Is vent high limit
switch in normally
closed position?
Refer to ignition
module/control board
illustration. Is there 24VAC
between blue and yellow
wires at location J8?
Is there 120VAC
across white and
black wires at the
blower? (see
image at right).
120 VAC
check at
blower