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STEP
ACTION
YES
NO
GO TO
18.
Does status code 21 ever flash?
11
19
—
19.
Go to page number indicated in Index for CLEANUP AND START-UP IN-
STRUCTIONS. If problem persists on an intermittent basis, replace 2-stage fur-
nace control. If problem still persists on an intermittent basis after replacing
2-stage furnace control, contact your distributor.
—
—
INDEX
Status Code 22
ABNORMAL FLAME-PROVING SIGNAL—THIS STATUS CODE INDICATES FLAME SIGNAL WAS SENSED WHILE GAS VALVE
GV WAS DE-ENERGIZED. THE INDUCER WILL RUN UNTIL FAULT IS CLEARED.
STEP
ACTION
YES
NO
GO TO
1.
Turn off gas to furnace by shutting off external manual shutoff valve.
—
—
2
2.
Does status code 22 stop flashing?
3
4
—
3.
Replace gas valve.
—
—
5
4.
Replace 2-stage furnace control.
—
—
5
5.
Go to page number indicated in Index for CLEANUP AND START-UP IN-
STRUCTIONS.
—
—
INDEX
Status Code 23
LOW-HEAT PRESSURE SWITCH DID NOT OPEN—THIS STATUS CODE INDICATES LOW-HEAT PRESSURE SWITCH LPS IS
MADE WHEN A CALL FOR HEAT IS INITIATED. THE 2-STAGE FURNACE CONTROL WILL FLASH STATUS CODE 23 UNTIL
SWITCH OPENS, THEN CYCLE BEGINS.
STEP
ACTION
YES
NO
GO TO
1.
Turn power off, remove blower door, and disconnect R thermostat lead.
—
—
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 Index for section covering the status code.
—
—
INDEX
7.
Go to page number indicated in Index for CLEANUP AND START-UP IN-
STRUCTIONS.
—
—
INDEX
8.
Do you have 24 vac across YELLOW wire on low-heat pressure switch LPS
and C
OM
-24V on 2-stage furnace control?
13
9
—
9.
Do you have 24 vac across connector terminal PL1-5 and C
OM
-24V on 2-stage
furnace control?
10
12
—
10.
The main harness is miswired.
—
—
11
11.
Rewire low-heat pressure switch LPS per wiring diagram.
—
—
7
12.
Replace 2-stage furnace control.
—
—
7
13.
Is low-heat pressure switch LPS wired correctly?
14
11
—
14.
Replace pressure switch assembly.
—
—
7
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