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Carrier 30GN040-420 Refrigerator User Manual

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Code 21 Reset thermistor failure (applies only to installa-

tions having external temperature reset) (alert)

If temperature measured by this thermistor is outside range

of –40 to 240 F (–40 to 116 C), reset function is disabled and

unit controls to normal set point. If temperature returns to

the acceptable range, reset function is automatically en-

abled. The cause of this fault is usually a bad thermistor,

wiring error, or loose connection.

Code 22 Compressor A1 discharge pressure

transducer failure (alert)

Code 23 Compressor B1 discharge pressure

transducer failure (alert)

Code 24 Compressor A1 suction pressure transducer

failure (alert)

Code 25 Compressor B1 suction pressure transducer

failure (alert)

Code 26 Compressor A1 oil pressure transducer failure (alert)

Code 27 Compressor B1 oil pressure transducer failure (alert)

If output voltage of any of these transducers is greater than

5 v, affected circuit shuts down without going through pum-

pout process (Alerts 24-27). Other circuit continues to run.

Reset is automatic if output voltage returns to the acceptable

range, and circuit start-up follows normal sequence. The cause

of this fault is usually a bad transducer or a wiring error.

Code 28 Low transducer supply voltage (alarm)

If transducer supply voltage is less than 4.5 v or greater

than 5.5 v, unit shuts down without going through pumpout

process. Reset is automatic if supply voltage returns to the

acceptable range, and circuit start-up follows normal se-

quence. The cause of this fault is usually a faulty trans-

former or primary voltage is out of range.

LEGEND

C—Contactor

CB — Circuit Breaker

COM, COMM — Communications Bus

CPCS — Compressor Protection

Control Module

CR — Compressor Contactor Relay

DGT — Discharge Gas Thermostat (Optional)

DSIO — Relay Module (Low Voltage)

HPS — High-Pressure Switch

LV — Low Voltage

NC — Normally Closed

NO — Normally Open

PL — Plug

PWR — Power

SNB — Snubber

TB — Terminal Block

TRAN — Transformer

U—Unloader

Fig. 11A — 24-V Safety Circuit Wiring (040-070)

51

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