Bryant 355CAV A Series Troubleshooting Manual page 25

STEP
16. Fix problem.
17. Does status code 32 flash once then flash status code 43?
18. On propane installations the propane tank may be low otherwise you may have a loose
connection between the low heat pressure switch LPS and the variable speed furnace control.
This includes the ORANGE wire interconnecting the low heat pressure switch LPS to the
variable speed furnace control.
19. Check all the tubing and tee fittings between the collector box and the GRAY side of each
pressure switch assembly. There should be no blockages or leaks in any of the tubing or the
tee fittings.
20. Were there any leaks or blockages in the tubing or tee fittings?
21. Turn power off and disconnect jumper wire across R and W/W1 thermostat terminals.
22. 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.
23. Turn power on and jumper R and W/W1 thermostat terminals.
24. Do you have at least 0.60 in. wc pressure drop across heat exchangers when fault occurs?
25. Replace the pressure switch assembly.
26. Is inducer motor rotating in direction indicated on the inducer housing?
27. Replace inducer motor or inducer motor assembly.
28. Turn power off.
29. Is inducer wheel okay?
30. If possible, replace inducer wheel. Otherwise, replace inducer motor assembly.
31. Is the inducer wheel properly mounted to the inducer motor shaft?
32. Is there any frost build-up on the combustion-air inlet?
33. The problem is caused by reversed vent and combustion-air pipes or some other moist air
entering combustion-air pipe.
34. You have excessive restriction in combustion-air or vent pipe. Also check for proper vent
sizing for installation.
35. Continue to observe furnace operation for 20 minutes or until status code starts flashing.
36. Does status code 32 flash?
37. Does a different status code flash?
38. Turn power off and disconnect jumper wire across R and W/W1 thermostat terminals.
39. 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.
40. Turn power on and jumper R and W/W1 thermostat terminals.
41. Monitor slope manometer. Does the pressure reading appear to be stable when fault occurs?
42. Check for a sag in vent pipe or partially clogged drain trap or line. Also check for improperly
plumbed drainage tubing within furnace. Install combustion air disk if not used or add
additional restriction to combustion-air inlet.
43. Does the pressure reading slowly drop off before flashing status code 32?
44. Problem could be caused by excessive wind conditions. If so the furnace will run the next
cycle in high heat. Check wiring for an intermittent connection in low heat pressure switch
LPS circuit. If problem still persists, and wind conditions are not excessive then replace
pressure switch assembly.
45. Check for partially clogged drain trap or line. If furnace is installed in the horizontal position
make sure the furnace is pitched forward ¼ inch minimum to ½ inch maximum. If furnace is
installed in the upflow or downflow position make sure the furnace is level or pitched forward
within ½ inch.
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