STEP ACTION YES NO GO TO
36
Remove tape from door switch and turn power off at main
disconnect.
37
37
Disconnect both multi-pin connectors from blower control
module attached to the blower motor. Be sure to depress
release latches on connectors or they may get damaged.
38
38
Remove control box assembly from blower shelf and posi-
tion out of the way.
39
39 Remove blower assembly from furnace. 40
40
Remove two phillips head or two ¼-in. hex head bolts from
blower control module attached to blower motor.
41
41
Carefully lift blower control module off blower motor. De-
press latch on internal connector to disconnect blower con-
trol module from motor portion of blower motor. DO NOT
PULL ON WIRES. GRIP PLUG ONLY.
42
42
When blower control module is completely detached from
blower motor, verify with standard ohmmeter that the resis-
tance from each motor lead in motor plug to unpainted mo-
tor end plate is greater than 100k ohms. Then verify motor
windings are not shorted or open by measuring resistance
between each combination of pins in motor plug (there are
three different combinations, pin 1-2, pin 2-3, and pin 1-3).
Resistance should be approximately equal across each
combination of pins.
43
43 Did the motor pass the resistance check? 44 46
44
Does blower wheel turn freely with blower control module
removed?
45 46
45
Replace blower control module. Inspect failed blower con-
trol module for water damage. If present, find source of wa-
ter and fix. Check A-coil and/or humidifier.
8
46
Replace entire blower motor including blower control mod-
ule. Inspect blower control module for water damage. If
present, find source of water and fix. Check A-coil and/or
humidifier.
8
Status Code 42
INDUCER MOTOR FAULT - This status code indicates the inducer has not started within 20 seconds after a call for heat, the inducer RPM
is outside its valid range of operation, or the inducer RPM signal was lost for 5 seconds during operation.
STEP ACTION YES NO GO TO
1
Shut the power off, remove the blower access panel and
disconnect the R thermostat lead from the furnace control
board.
2
2
Turn the power on and depress the door switch. Use a
piece of tape to hold it closed.
3
3 Jumper the R and W/W1 thermostat terminals. 4
4
Observe the operation of the furnace for the next 8 minutes
or until fault occurs.
5
5 Does status code 42 flash? 9 6
6 Does a different status code flash? 7 54
7
Go to page number indicated in the Index for the section
covering the status code.
INDEX
8
Go to page number Indicated in Index for CLEANUP AND
START-UP INSTRUCTIONS
INDEX
9 Does the inducer motor turn on? 27 10
10
Hook an AC voltmeter across PL2-4 and NEUTRAL-L2 on
the variable speed furnace control. Is 115-vac across PL2-3
and NEUTRAL-L2?
12 11
11 Replace the variable speed furnace control. 8
12 Do you have 115-vac across PL11-6 and PL11-12? 14 13
13
You have an open wire or bad terminal on either the
BLACK or WHITE wire between the variable speed furnace
control and the inducer motor. Repair or replace main wire
harness.
8
14
Are all pins and wire leads in tact on connectors between
variable speed furnace control and the inducer motor?
16 15
15 Fix problem. 8
16
Turn power off and disconnect jumper wire across R and
W/W1 thermostat terminals.
17
31
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