Carrier 58MVP - Manual (Page 25)

9. Go to page number indicated in Index for CLEANUP AND START-UP INSTRUCTIONS. — — INDEX
10.
Consider this fault like a Fault Code 13 and go to page number indicated in Index for Fault Code
13.
— — INDEX
11. Do you have 24v between terminals PL1-9 and C? 13 12 —
12. Replace furnace control board. — — 9
13. Do you have 24v between terminals PL1-11 and C? 12 15 —
14. You have an open RED wire or bad terminal in limit circuit. Repair or replace it. — — 9
15. Turn power off. — — 16
16. Do you have continuity across limit switch LS? 20 17 —
17. Wait for unit to cool then recheck for continuity across limit switch LS. — — 18
18. Do you have continuity across limit switch LS? 20 19 —
19. Replace limit switch. — — 9
20. Do you have continuity across flame rollout switch FRS? 28 21 —
21. Can flame rollout switch FRS be reset? 23 22 —
22. Replace flame rollout switch. — — 9
23.
Reset flame rollout switch FRS, turn power on, and observe furnace operation for (2) 15 minute
cycles.
— — 24
24. Does flame rollout switch trip again? 26 25 —
25. Does a different fault occur? 8 9 —
26.
You have inadequate combustion-air supply. This may be caused by:
• Reversed vent and combustion-air pipes.
• Poor burner, manifold, or orifice alignment.
• Leak somewhere between primary and secondary heat exchangers.
• Leak in secondary heat exchanger.
• Internal restriction in coupling box or secondary heat exchanger.
— — 27
27. Fix problem. — — 9
28. Do you have continuity across auxiliary limit switch ALS? 14 29 —
29. Can auxiliary limit switch ALS be reset? 31 30 —
30. Replace auxiliary limit switch. — — 9
31.
Reset auxiliary limit switch ALS, replace blower access panel, turn power on, set thermostat to call
for heat or jumper R and W/W1 thermostat terminals, and observe furnace operation for 15 minutes.
— — 32
32. Does fault occur again? 38 33 —
33. Does a different fault occur? 8 34 —
34. Is this unit in downflow or horizontal position? 35 9 —
35.
Disconnect R thermostat lead, wait for blower to stop, and continue to observe unit for 5 more min-
utes.
— — 36
36. Does fault occur after blower stops? 37 9 —
37.
Increase blower off delay time to 225 sec by putting both setup switches SW-7 and SW-8 in ON
position.
— — 27
38.
Does furnace have proper limit switch, limit shield, blower baffle (if used), rear air baffle (if used),
and auxiliary limit switch? If so, are limit switch, limit shield, and heat exchangers properly aligned?
39 27 —
39.
Change limit switch first. If problem still exists, replace auxiliary limit switch. One of these switches
is out of calibration.
— — 9
40. Does fault occur during low fire? 41 42 —
41.
On the third burner cycle, unit will run in high-fire mode and flash fault code continuously. The unit
is locked into high-fire-only mode. Verify the following before going to Step 10:
• If unit has a bypass humidifier, make sure setup switch SW-3 is in ON position.
• If unit is installed in a zone system, make sure setup switch SW-5 is in ON position.
• Check low-fire rate. Clock input rate. DO NOT use manifold pressure method unless using
propane.
— — 10
42.
Verify the following before going to Step 10:
• If unit is installed in a zone system, make sure setup switch SW-5 is in ON position.
• Check high-fire rate. Clock input rate. DO NOT use manifold pressure method unless using
propane.
— — 10
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