28
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 photo
at right)?
Determine
power
source
problem
and
correct
Check amp draw
through BLACK wire
lead of blower motor. Is
there .6 to 3.0 amps?
Is blower wheel
secured to blower
motor shaft?
Call for
technical
support.
Replace blower. (See
“Blower Replacement
Procedure”.)
Refer to ignition
module/control board
illustration. Is there 24VAC
between blue and yellow
wires at location
J8
?
Is collector high limit
switch in normally
closed position?
Correct safety circuit
problem per safety
circuit trace. (See
Blocked Vent Pressure
Switch Testing”.)
Replace ignition
module/control
board.
Is there 120VAC
across white and
black wires at the
blower? (See
photo at right.)
Repair/replace wire
harness.
Replace blower. (See
“Blower Replacement
Procedure”.)
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
120 VAC check
at blower
28
