STEP
ACTION
YES
NO
GO TO
13
The thermostat and/or thermostat wires are loading down
the transformer. Replace the thermostat or repair thermo-
stat wires.
9
14
Does the hot surface ignitor HSI come on during the cycle?
15
19
15
Disconnect the humidifier lead from HUM terminal on vari-
able speed furnace control.
16
16
Does the furnace still alternately cycle induced draft motor
IDM and blower motor BLWM as described in Step 4.
18
17
17
There is a direct short in wiring to humidifier solenoid coil,
diode bridge(if used), or humidifier solenoid coil.
8
18
There is a short in the gas valve GV or wiring to gas valve
GV. Refer to Appendix E to check gas valve GV.
8
19
There is a direct short in the ORANGE wire from the low
heat pressure switch LPS.
8
20
While the unit is operating in low heat jumper R and W2
thermostat terminals.
21
21
Does the furnace abruptly shut down with no inducer post
purge and then run blower motor BLWM for 90 seconds
while AMBER LED status light flashes status code 12.
22
26
22
Disconnect BROWN wire to gas valve GV.
23
23
Does the furnace still abruptly shut down as described in
Step 21.
25
24
24
Replace gas valve.
9
25
There is a direct short to ground in the GRAY or BROWN
wires connected to the high heat pressure switch HPS.
8
26
Power to the furnace was probably interrupted or line volt-
age was too low during a call for heat. This is normal op-
eration. Go to the page number indicated in Index for the
CLEANUP AND STARTUP INSTRUCTIONS.
INDEX
Status Code 13
LIMIT CIRCUIT LOCKOUT - Lockout occurs if the limit or flame rollout switch is open longer than 3 minutes or 10 successive limit trips
occurred during high-heat. The variable speed furnace control will auto-reset in 3 hours. Flame roll-out switch FRS requires manual-reset.
STEP
ACTION
YES
NO
GO TO
1
Remove the blower access panel. Make sure the thermo-
stat is NOT calling for heat.
2
2
Depress the door switch. Use piece of tape to hold it
closed.
3
3
Does status code 33 flash?
11
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
Set thermostat to call for heat or jumper R and W/W1 ther-
mostat terminals.
7
7
Observe the furnace operation for 25 minutes or until status
code starts flashing.
8
8
Does status code 33 flash?
26
9
9
Does a different status code flash?
5
10
10
Go to page number indicated in Index for CLEANUP AND
START-UP INSTRUCTIONS.
INDEX
11
Is 24-vac across connector terminal PL1-6 and C
OM
-24V on
variable speed furnace control?
13
12
12
Replace the variable speed furnace control.
10
13
Is 24-vac across connector terminal PL1-8 and C
OM
-24V on
variable speed furnace control?
12
14
14
Turn power off.
15
15
Do you have continuity across limit switch LS?
17
16
16
Replace limit switch LS.
10
17
Do you have continuity across the flame rollout switch
FRS?
25
18
18
Can flame rollout switch FRS be reset?
20
19
19
Replace flame rollout switch FRS.
10
20
Reset flame rollout switch FRS, turn power on, and observe
furnace operation for (2) 15 minute cycles.
21
21
Does the flame rollout switch FRS trip again?
23
22
15