Ingersoll-Rand M952V060BD36AB, Service Facts

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31
Service Facts
M952-SF-4
YES
YES
Is pressure greater
than pressure
switch label?
See Note #2
Replace pressure switch.
Check operation.
Is the inducer
motor running?
Is 24 volts present,
measured across PS1
(orange to yellow/6)?
See Note #1
Disconnect electrical
power from the furnace
and remove 1 wire from
each pressure switch
Is continuity
measured across
PS1 or PS2?
Replace pressure switch.
Check operation.
YES
NO
Note #1
24 volts = Open Switch
0 volts = Closed Switch
DEFINITION
An error has occurred with the PS1 or PS2.
The error will be reported, indicating that the pressure switch
is either opened or closed, contrary to normal operating
sequence.
In most cases, the pressure switch is not the problem.
Note: Verify all wiring to pressure switch is
correct per wiring diagram Note #2
Measured pressure is
negative, greater than refers
to magnitude only.
3 Flash Fault LED
NO
Replace Inducer.
Check operation.
YES
While the furnace is operating on 1
st
stage heat make a call for 2
nd
stage
heat. Allow (30 seconds) for the
furnace to transition to 2
nd
stage.
Is 24 volts present,
measured across PS2
(yellow/7 to brown)?
See Note #1
Is pressure greater
than pressure
switch label?
See Note #2
NO
Replace pressure switch.
Check operation.
Cycle power to the furnace
and call for 1
st
stage heat.
NO
YES
NO
Replace or repair wiring
harness. Check operation.
YES
NO
Reconnect electrical
power to furnace. Cycle
power to furnace and call
for 1
st
stage heat.
Does the
furnace run on
1
st
stage?
YES
Check PS hose, flue piping for
obstruction and/or confirm vent
size is correct
Check PS hose, flue piping
for obstruction and/or
confirm vent size is correct
Pressure
switch is okay.
Pressure switches
are okay. Re attach
each wire to PS
Is voltage measured at
IFC plug between pins
1 (BK/6) – 2 (RD/6)
2 (RD/6) – 3 (WH/6)
1 (BK/6) – 3 (WH/6)?
NO
YES
YES
YES
See IFC Component Layout for
location of plug.
Is voltage measured at
inducer motor plug
between pins
1 (BK) – 2 (RD)
2 (RD) – 3 (WH)
1 (BK) – 3 (WH)?
NO
Replace IFC.
Check operation.
NO
Pressure
switch is okay.