Trane S9V2B040U3PSBC/D Installation, Operation And Maintenance Manual page 109

DEFINITION
An error has occurred with the PS2 indica ng that the pressure
switch is open when it should be closed.
In most cases, the pressure switch is not the problem.
NOTE: Verify pressure switch wiring and tube rou ng are correct.
S9V2-SVX001-1A-EN
3.4 Fault Code
Cycle power to the furnace
and call for 2nd stage heat.
Pressure switch measured across PS2
NO
is okay.
than pressure switch
Check PS hose, flue piping for
obstruc on and confirm vent size is
Is PS2 oriented
correctly for the NO
applica on?
YES
Is the inducer
NO
motor running?
YES
Is 24 volts present,
(orange to yellow)?
See Note #1
YES
Is pressure greater
YES
label?
See Note #2
NO
correct
T T r r o o u u b b l l e e s s h h o o o o t t i i n n g g
Note #1
24 volts = Open Switch
0 volts = Closed Switch
Note #2
Measured pressure is
nega ve, greater than refers
to magnitude only.
Correct orienta on
See this document
Is voltage measured
from
RD- WH
NO
BK-RD
BK-WH
at the inducer motor?
YES
Call Technical Support
Replace pressure switch.
Check opera on.
Replace inducer
assembly
109