- 16 -
STEP ACTION YES
NO
GO
TO
7.
Go to page number indicated in the Index for the section covering the status code.
INDEX
8.
Remove blower access panel and depress door switch. Use a piece of tape to hold switch
closed.
9
9.
Jumper R and W/W1 thermostat terminals.
10
10.
Does status code 21 start flashing when the low heat pressure switch LPS makes?
11
12
11.
Replace the variable speed furnace control.
5
12.
Does a different status code flash?
7
13
13.
Disconnect the jumper wire across R and W/W1 thermostat terminals and wait until the blower
stops.
14
14.
Jumper R, W/W1, and W2 thermostat terminals on the variable speed furnace control.
15
15.
Does status code 21 start flashing when the high heat pressure switch HPS makes?
16
17
16.
The BLUE and GREEN wires to gas valve GV are reversed.
4
17.
Cycle the furnace several times to check for intermittent operation.
18
18.
Does status code 21 ever flash?
11
19
19.
Go to page number indicated in Index for CLEANUP AND START-UP INSTRUCTIONS. If
the problem persists on an intermittent basis, replace the variable speed furnace control. If
problem still persists on an intermittent basis after replacing the variable speed furnace control,
contact your distributor.
INDEX
Status Code 22
ABNORMAL FLAME-PROVING SIGNAL - This status code indicates the flame signal was sensed while gas valve GV was de-
energized. The inducer will run until the fault is cleared.
STEP ACTION YES
NO
GO
TO
1.
Turn off gas to the furnace by shutting off the external manual shut-off valve.
2
2.
Does status code 22 stop flashing?
3
4
3.
Replace the gas valve.
8
4.
Disconnect wire from the flame-proving sensor electrode FSE.
8
5.
Does status code 22 stop flashing?
6
7
6.
Clean flame sensor with fine steel wool. Inspect burner box assembly and remove any carbon
deposits near the flame sensor opening.
8
7.
Replace the variable speed furnace control.
8
8.
Go to page number indicated in Index for CLEANUP AND START-UP INSTRUCTIONS.
INDEX
Status Code 23
PRESSURE SWITCH DID NOT OPEN - This status code indicates the low or high heat pressure switch LPS or HPS is made
when a call for heat is initiated. The variable speed furnace control will flash status code 23 until the switch opens, then cycle
begins.
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.
Does status code 23 flash?
8
5
5.
Does a different status code flash?
6
7
6.
Go to page number indicated in the Index for the section covering the status code.
INDEX
7.
Go to page number indicated in Index for CLEANUP AND START-UP INSTRUCTIONS.
INDEX
8.
Is the inducer motor ON?
21
9
9.
Is 24-vac across ORANGE wire on the low heat pressure switch LPS and C
OM
-24V on
variable speed furnace control?
16 10
10.
Is 24-vac across connector terminal PL1-4 and C
OM
-24V on variable speed furnace control?
11
13
11.
The main harness is miswired.
7
12.
Rewire low heat pressure switch LPS per the wiring diagram.
7
13.
Is 24-vac across BROWN wire on the high heat pressure switch HPS and C
OM
-24V on
variable speed furnace control?
18 14
14.
Is 24-vac across connector terminal PL1-3 and C
OM
-24V on variable speed furnace control?
11
15
