- 21 -
STEP ACTION YES NO GO TO
28. Is inducer wheel okay? 30 29
29. If possible, replace inducer wheel. Otherwise, replace inducer motor assembly. 8
30. Is the inducer wheel properly mounted to the inducer motor shaft? 31 32
31. Is there any frost build-up on the combustion-air inlet? 14 33
32. Fix problem. 8
33. You have excessive restriction in combustion-air or vent pipe. Also check for proper vent
sizing for installation.
32
34. Continue to observe furnace operation for 20 minutes or until status code starts flashing. 35
35. Does status code 31 flash? 37 36
36. Does a different status code flash? 7 43
37. Turn power off and disconnect jumper wire across R, W/W1, and W2 thermostat terminals. 38
38. Connect 1 side of slope manometer with a tee to collector box pressure tap. Connect other side
with a tee to gas valve pressure fitting. Refer to pressure check diagram in Appendix C.
39
39. Turn power on and jumper R, W/W1, and W2 thermostat terminals. 40
40. Monitor slope manometer. Does the pressure reading appear to be stable when fault occurs? 41 42
41. Replace pressure switch assembly. If problem persists, check wiring for an intermittent
connection in high heat pressure switch HPS circuit.
8
42. Check for a sag in vent pipe or partially clogged drain trap or line. Also check for improperly
plumbed drainage tubing within furnace.
8
43. Disconnect jumper wire across R, W/W1, and W2 thermostat terminals and wait for the blower
off-delay to finish.
44
44. Reset the power and jumper R and W/W1 thermostat terminals. 45
45. Does status code 31 flash? 47 46
46. Does a different status code flash? 7 8
47. Turn power off and disconnect the GRAY wire to the high heat pressure switch HPS. 48
48. Turn power ON and jumper R and W/W1 thermostat terminals. 49
49. Does status code 31 flash? 50 13
50. The BROWN wire is shorting to the ORANGE wire that goes the low heat pressure switch
LPS. Reconnect the GRAY wire to the high heat pressure switch HPS.
12
Status Code 32
LOW-HEAT PRESSURE SWITCH DID NOT CLOSE OR REOPENED - This status code can occur as a result of the low heat
pressure switch LPS not making or the low gas pressure switch LGPS opening. Regardless of which switch is open, the
variable speed furnace control will operate under the scenarios shown below. Keep in mind that whenever the variable speed
furnace control shuts unit down, gas remains off or shuts off immediately and inducer continues running for 15 seconds.
- LOW HEAT
1. PREPURGE - If the low heat pressure switch LPS does not make within 45 seconds after a call for heat is initiated the variable speed furnace
control starts flashing status code 32, shuts unit down, waits 2 minutes, stops flashing status code 32, and restarts the heating cycle.
2. AFTER IGNITION - If the low heat pressure switch LPS opens after the burners ignite the variable speed furnace control starts flashing
status code 32, shuts unit down, turns on the blower, or continues to operate the blower, at low heat airflow for the selected blower off-delay
period, stops flashing status code 32, and restarts the heating cycle.
STEP ACTION YES NO GO TO
1. Turn power off, remove blower access panel, and disconnect User Interface ABCD connector
(if used) or the R thermostat lead (if used) from the furnace control board.
2
2. Turn power on and depress door switch. Use a piece of tape to hold switch closed. 3
3. Jumper R and W/W1 thermostat terminals. 4
4. Observe operation of the inducer motor for 1 minute before proceeding to the next step. 5
5. Does status code 32 flash? 9 6
6. Does a different status code flash? 7 35
7. Return setup switch SW1-2 to its original setting and go to page number indicated in the Index
for the section covering the status code.
INDEX
8. Return setup switch SW1-2 to its original setting and go to page number indicated in Index for
CLEANUP AND START-UP INSTRUCTIONS.
INDEX
9. Is 24-vac across YELLOW wire to the low heat pressure switch LPS and COM-24V on
variable speed furnace control?
12 10
10. Is 24-vac across connector terminal PL1-2 and COM-24V on variable speed furnace control? 11 13
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