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UTILITY RELAY *

UTILITY SIGNAL

'_ OPEN RELAY

* SUPPLIED BY UTILITY PROVIDER

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A05247

Fig. 18 - 2-Stage HP/AC Control Board

STATUS CODE 21 - GAS HEATING LOCKOUT

Control will NOT auto reset. Check for mis-wired gas valve or defective control (valve relay).

STATUS CODE 22 ABNORMAL FLAME-PROVING SIGNAL

Flame is proved while gas valve is de-energized. Inducer will run

until fault is cleared. Check for leaky gas valve or stuck-open gas valve.

STATUS CODE 23 - PRESSURE SWITCH DID NOT OPEN

Check for obstructed pressure tubing or pressure switch stuck closed.

STATUS CODE 24 - SECONDARY VOLTAGE FUSE IS OPEN Check for short circuit in secondary voltage (24VAC) wiring.

STATUS CODE 25 - INVALID MODEL SELECTION OR SETUP ERROR

Indicates either the model plug is missing or incorrect. If code

flashes 4 times on power-up, control is defaulting to model selection stored in memory. Check for proper model plug number and resistance values per wiring diagram.

STATUS CODE 31, 32 - PRESSURE SWITCH OR RELAY DID NOT CLOSE OR REOPENED

Control relay may be defective. If open longer than five minutes, inducer shuts off for 15 minutes before retry. If open during blower

on-delay period, blower will come on for the selected blower

off-delay. Check for excessive wind, restricted vent, defective

inducer motor, defective pressure switch, lower inducer voltage

(230VAC), inadequate combustion air supply, disconnected or

obstructed pressure tubing, or low inlet gas pressure (if LGPS used).

STATUS CODE 33 - LIMIT CIRCUIT FAULT

Indicates a limit or flame rollout switch is open. Blower will run for 4 minutes or until open switch remakes, whichever is longer. If

open longer than 3 minutes, code changes to lockout 13. If open

less than 3 minutes status code 33 continues to flash until blower shuts off. Check for loose blower wheel, restricted vent, excessive

wind, dirty filter or restricted duct system, defective switch or

connections, or inadequate combustion air supply (flame roll-out switch open).

STATUS CODE 34 - IGNITION PROVING FAILURE

Control will try three more times before lockout 14 occurs. If flame

signal lost during blower on-delay period, blower will come on for

the selected blower off-delay. Check for oxide buildup on flame sensor (clean with fine steel wool), proper flame sense microamps

(.5 microamps D.C. min., 4.0-6.0 nominal), manual valve shutoff,

low inlet gas pressure, control ground continuity, gas valve

defective or turned off, flame sensor must not be grounded,

inadequate flame carryover or rough ignition, or green/yellow wire must be connected to unit sheet metal.

STATUS CODE 41 - BLOWER MOTOR FAULT

Indicates the blower failed to reach 250 RPM or the blower failed

to communicate within the prescribed time limits. Thirty seconds

after being turned ON or ten seconds during steady-state operation.

STATUS CODE 45 - CONTROL CIRCUITRY LOCKOUT

Auto reset after one hour lockout due to gas valve relay stuck open, flame sense circuit failure, or software check error. Reset power to clear lockout. Replace control if status code repeats.

E. HP/AC Control Troubleshooting

See Table 4 for HP/AC control board status codes and

troubleshooting information.

STATUS CODE 53, OUTDOOR AIR TEMPERATURE

SENSOR FAULT - DETAILED DESCRIPTION

If an OAT sensor is found at power-up, input is constantly checked

to be within a valid temperature range. If sensor is found to be

open or shorted at any time after initial validation, Status Code 53

will be displayed at amber STATUS LED.

Check for faults in wiring connecting sensor to OAT terminals.

Using an Ohm meter, check resistance of thermistor for a short or open condition.

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