25 INVALID MODEL SELECTION OR
SETUP ERROR–Ifstatuscode25only
flashes 4 times on power-up the control is
missing its model plug PL4 and is
defaulting to the model selection stored in
memory. If status code 25 flashes
continuously it could indicate any of the
following:
- Model plug PL4 is missing and there is
no valid model stored in permanent
memory. This will happen if you forget
to install the model plug PL4 on a
servi ce repl acem en t co nt rol .
- Thermostat call with SW1-1 ON.
- Thermostat call with SW1-6 ON.
-SW1-1a
nd SW1-6 both ON.
- Two different furnace models twinned.
- Service replacement cont rol is incorrect .
Need non-modulating board with
software version V17 or later.
31 HIGH-HEAT PRESSURESWITCH OR
RELAY DID NOT CLOSE OR
REO P ENED - Check for:
- Control relay may be defective.
- Gas valve is miswired.
-Seestatuscode32.
41 BLOWERMOTOR FAULT – Indicates the
blower failed to reach 250 RPM or the
blower failed to communicate within the
prescribed time limits. Thirty seconds
after being t urned ON or ten seconds
during steady-state operation. Turn power
of fand check the following items first
before proceeding to the next step.
- Rubbing blower wheel.
- Loose blower wheel.
- Wiring from furnace control to blower
motor.
Remove the Rthermostat connection from
the furnace control, disconnect both
connectors from the blower
motor PL13
and PL14. Does the blower wheel turn
freely?
Replace the blower control module attached to
the blower motor. Follow the instructions with
the blower control module to make sure the
entire blower mot or does not need t o be
replaced.
Turn power back on. Is there 115VAC at
PL 14- 5 an d PL14 -4?
Youhaveanopenwireorbad
terminal on either the BLACK or
WHITE power leads bet ween
the furnace cont rol and t he
blower motor. If you have a
power choke disconnect it and
check continuit y.
YES
YES
NO
NO
Is there 12-VDC at PL13-7 RED (+) and
PL 13- 1 GRE EN(-)?
YES
NO
Is t here 12-VDC at PL3-1 RED (+) and
PL 3-2 GREEN(-)?
Replace the furnace control.
NO
Youhaveanopenwireorbad
terminal on either the RED or
GRE ENwirebetweenthe
furnace control and the blower
motor.
YES
Is there 5-VDC at PL13-16 YELLOW (+)
and PL13-1 GREEN(-)?
Is t here 5-VDC at PL3-3
YELLOW ( + ) an d PL3- 2
GRE EN (-)?
NO
NO
Youhaveanopenwireorbad
terminal on the YELLOW wire
between the furnace control and
the blower motor.
YES
YES
The vol t ag e j ust measu red sh oul d b e
verystableandshouldnotfluctuatemore
than .02-VDC. If the voltage fluctuates
more than thisget a different voltmeter
before proceeding.
Tur n power of f , discon nect PL13 a nd
PL14 from the blower motor, then turn
power back on. Connect a DC voltmeter
across PL13-16 BLUE (+ ) and PL13-1
GRE EN (-). The voltage should be near
0-VDCbut it will fluctuate brieflyseveral
times a second. If you have an analog
voltmeter the needle will briefly go high
several times a second. If you have a
digital voltmeter with a bar graph it will
sho w a lar g e ch an ge i n m agni t ud e o n t he
bar graph several times a second. If you
have a standard digital voltmeter it will
sho w a b ri
effluctuation in voltage and t he
magnitude may vary depending on the
voltmeter used.
Does the voltage fluctuate as described in the
previous step?
Connect a DC voltmeter across PL3-4 BLUE
(+) and PL3-2 GREEN (-). Does the voltage
fluctuate as described two steps back?
You have an open wire or bad terminal on the
BLUEwire between the furnace control and the
blower motor.
NO
Replace the furnace control.
YES
Tur n power of f , reconnect PL13 and
PL14 to the blower motor, then turn
power back on. Connect a DC voltmeter
across PL3-3 YELLOW (+) and PL3-2
GRE EN (-). Does the voltage fluctuate
more than it did in the previous step?
NO
YES
YES
NO
Replace the blower control module attached to
the blower motor. Follow the instructions with
the blower control module to make sure the
entire blower mot or does not need t o be
replaced.
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