58SU0A (Series 2 & 3): Troubleshooting Guide
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
11
Status Code 13 - Limit Circuit Lockout
Lockout occurs if a limit, draft safeguard, burner thermal switch or blocked vent switch (if used) or blower auxiliary limit switch is open.
Control will auto-reset after three hours. Blower will run for 4 minutes or until limit switch closes, whichever is longer.
STEP ACTION YES NO GO TO
1.
Turn power off, remove the blower access panel, and disconnect the R thermostat lead from the
furnace control board.
2
2. Depress the blower door switch. Use a piece of tape to hold it closed. Turn power on 3
3. Does status code 13 flash? 24 4
4. Does a different status code flash? 5 6
5. Go to page number indicated in the Index for the section covering the status code. INDEX
6. Jumper R and W thermostat terminals. 7
7. Observe the furnace operation for at least 20 minutes or until status code starts flashing. 8
8. Does status code 13 flash? 12 9
9. Does a different status code flash? 5 11
10. Fix Problem 11
11. Go to page number indicated in Index for CLEANUP AND START- UP INSTRUCTIONS. INDEX
12. Did blower motor start? 21 13
13.
Hook an AC voltmeter across PL15 L1 Black (+) and PL15 L2 White (-). Is 115-VAC across PL15 L1
Black (+) and PL15 L2 White (-)?
17 14
14. Is the Black L1 blower lead connected to the BL motor output on the furnace control? 15 10
15. Is the White L2 blower lead connected to one of the Neutral-L2 output taps on the furnace control? 16 10
16.
You have an open wire or bad terminal on either the BLACK L1 or WHITE L2 wire between the furnace
control and the blower motor. Repair or replace blower motor harness.
10
17.
Hook an AC voltmeter across the Blower Heat speed output tap (+) and the blower COM connection (-)
at the 24V MTR tap connections on the furnace control. Is 24-VAC across Blower Heat speed output tap
(+) and the blower COM connection (-)?
18 29
18.
Hook an AC voltmeter across the PL16 blower lead attached to heat speed (+) and PL15 Com GREEN
(-) at blower motor. Is 24-VAC across the PL16 blower lead attached to heat speed (+) and PL15 Com
GREEN (-)?
19 20
19. Replace blower motor 10
20.
You have an open wire on either the heat speed tap or the blower speed COM of the 24V signal wires to
the blower motor.
10
21.
Remove jumper from the R and W terminals and allow blower motor to run for 10 minutes or until blower
shuts off
22
22. Did blower shut off before 10 minutes? 24 23
23. Turn power OFF 71
24. Is 24vac across connector terminal PL1-6 and COM-24V on the furnace control? 30 25
25. Turn power off 26
26. Disconnect PL1 from furnace control. 27
27.
Turn power off at main disconnect, remove tape from door switch, and remove jumper across
R and W/W1.
28
28. Is blower wheel firmly mounted on motor shaft? 29 24
29.
Does the model plug PL4 match the part number specified on the Model Plug Chart in upper left-hand
corner of wiring schematic?
31 30
30. Replace model plug. 10
31.
Does furnace have the proper limit switch, limit shield, blower baffle (if used), and rear air baffle (if
used)? If so, are the limit switch, limit shield, and heat exchangers properly aligned?
27 24
32. Is blower wheel firmly mounted on the blower shaft? 33 10
33. Do you have continuity across limit switch (LS)? 50 34
34. Allow limit switch (LS) to cool for 10 minutes. Do you have continuity across the limit switch (LS)? 36 35
35. Replace limit switch (LS).
36.
Turn power on and jumper the R and W thermostat terminals. Allow furnace to operate for 20 minutes or
until status code starts flashing
37
37. Does status code 13 flash? 39 38
38. Does a different status code flash? 5 11
39.
Is the furnace considerably over-fired? (10% or more?) Clock input rate. Do not use manifold pressure
method.
40 41
40.
Ensure that gas inlet pressure and orifice is correct. Adjust gas valve pressure to achieve proper input
rate per the Installation, Start Up, and Operating Instructions.
10
41. Is temperature rise within range? 42 45
42. Turn power off and install a temperature probe in front of limit switch button. 43
43.
Turn power on and cycle unit. Does the limit switch open at a temperature at least 15 deg. F. below the
temperature setpoint of the switch? (Example - setpoint of switch is 175 deg. F. but switch opens at a
temperature below 160 deg. F.)
35 44
44.
Problem may be related to poor air distribution or excessive pressure drop across the filter. Check filter
and return air grills for blockage. Add turning vanes, more supply openings, or more return air openings.
10
45. Does the installation have a bypass humidifier or zoning system bypass? 46 48
46. Is temperature rise of return air from bypass greater than 15 deg. F? 47 48
47. Bypass is oversized. Adjust damper or replace with properly sized bypass. 10
48. Can blower speed be adjusted to raise airflow delivered? 49 44
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