Carrier PC 111 - page 46

Table 23 — Diagnostic Codes

NOTES:

1. Illegal unit configuration caused by missing programmable header or both unloader DIP switches on.

2. All auto. reset failures that cause the unit to stop will restart when the error has been corrected.

3. All manual reset errors must be reset by turning the control switch off and then back on.

4. Valid resistance range for the thermistors is 363,000 to 585 ohms.

5. Codes 53, 54, 57, 58, 61, 62, 65-69, 73, 74, and 77-80 are not used on these units.

CODES 59 AND 60: LOW-PRESSURE SWITCH — These

codes are used to indicate a low-pressure switch failure.

The processor monitors the low-pressure switch. If the

switch opens, either by low refrigerant charge, circuit failure,

or wiring error, the circuit is locked off. Code 59 indicates a

failure of the lead circuit, and as a result, that circuit will be

shut down. Code 60 indicates a failure of the lag circuit, and as

a result, that circuit will be shut down. These codes will only be

displayed when the display button is pressed. To reset the cir-

cuit, the ON-OFF switch must be turned to OFF, then ON

position.

CODES 63 AND 64: OIL PRESSURE SWITCH — These

codes are used to indicate an oil pressure switch failure. Since

the units do not have oil pressure switches, these codes are not

used. The terminals on the processor board must be jumpered

together or an error will occur. If these errors occur, check

jumper between J2-1 and J2-2 for a code 63, or between J2-3

and J2-4 for a code 64 to be sure jumper is properly connected.

To reset the circuit, the ON-OFF switch must be turned to OFF

and then to ON position.

CODE 70: ILLEGAL UNIT CONFIGURATION — If the

unit configuration header is not installed and properly config-

ured, and/or if DIP switches are not properly set, unit will not

start, and an error code of 70 will be indicated on display board

when display button is pushed. Check the header and DIP

switch settings.

CODES 71 TO 76: THERMISTOR/RESISTOR FAILURE —

If measured temperature of a thermistor is less than –60 F

(363,000 ohms) or greater than 180 F (585 ohms), the appro-

priate sensor error code (Table 23) will be displayed when

the display button is pushed. The unit will be shut down.

Thermistor failures will automatically reset once the er ror has

been corrected. If a failure occurs, the following are possible

causes:

Thermistor or Resistor Failure — A shorted or open ther-

mistor or resistor will cause the failure.

Wiring Failure — If a wiring error exists that causes a shorted

or open circuit, this will cause a failure.

Processor Board Failure — If circuitry on processor board

fails, this could cause an error.

The codes are designated as follows:

Code 71 Supply-Air Thermistor Failure

Code 72 Return-Air Thermistor Failure

Code 73 Not used

Code 74 Not used

Code 75 Circuit 1 Saturated Condensing Thermistor

Code 76 Circuit 2 Saturated Condensing Thermistor

CODE 81: RESET THERMISTOR OR POTENTIOMETER

FAILURE — This is a unique code since the reset temperature

potentiometer (P7) is in series with the space temperature ther-

mistor (T10). If either one of these components fail, reset will

be terminated. This error will automatically reset once the situ-

ation is corrected. If an error is detected, the most probable

cause is one of the following:

• Thermistor Failure — A shorted or open thermistor will

cause the failure.

• Potentiometer Failure — If the potentiometer is outside

of the valid range (40 to 90 F), a failure will result.

• Wiring Problem — If the circuit is open, a failure will be

detected.

• Processor Board Failure — If the processor board fails

(hardware), an alarm will be detected.

DISPLAY DESCRIPTION OF FAILURE ACTION TAKEN

BY CONTROL

RESET

METHOD PROBABLE CAUSE

Compressor 1 failure

Compressor 2 failure

Compressor 3 failure

Compressor 4 failure

Circuit 1 shut off

Circuit 2 shut off

Compressor 3 shut off

Compressor 4 shut off

Manual

High-pressure switch or high dis-

charge gas thermostat switch

trip, compressor ground current

>2.5 amp or compressor board

relay on when it is not supposed

to be on. Wiring error between

electronic control and compres-

sor protection module.

Loss-of-charge circuit 1

Loss-of-charge circuit 2

Circuit 1 shut off

Circuit 2 shut off

Manual

This indicates either a low refrig-

erant charge, or a loss-of-charge

switch failure.

Low oil pressure circuit 1

Low oil pressure circuit 2

Circuit 1 shut off

Circuit 2 shut off

Manual

Not used; Check jumper on pro-

cessor board.

70 Illegal unit configuration Unit will not start Manual Configuration error (see Note 1).

Supply-air thermistor failure

Return-air thermistor failure

Circuit 1 saturated condensing thermistor

Circuit 2 saturated condensing thermistor

Reset temperature thermistor failure

Unit shut off

Use default value

Unit shut off

Stop reset

Auto.

Thermistor or resistor failure, wir-

ing error, or thermistor or resistor

not connected to the processor

board.

Supply-air set point potentiometer failure

Economizer potentiometer failure

Reset limit set point potentiometer failure

Demand limit potentiometer failure

Minimum economizer potentiometer failure

Warm-up set point potentiometer failure

Use default value

Close economizer

Stop reset

Stop demand limit

Close economizer

Use default value

Auto.

Potentiometer improperly con-

nected, potentiometer setting out

of range, potentiometer failure or

wiring error.