Carrier 30GN040-420 operating instructions Comm

LEGEND

CÐ Contactor

CB	Ð Circuit Breaker
COMM	Ð Communications Bus
CPCS	Ð Compressor Protection Control Module
DGT	Ð Discharge Gas Thermostat (Optional)
DSIO	Ð Relay Module (Low Voltage)		*And associated modular units.
HPS	Ð	High-Pressure Switch
LV	Ð	Low Voltage
PL	Ð	Plug
PWR	Ð Power
TB	Ð	Terminal Block
TRAN	Ð	Transformer
U	Ð Unloader

Fig. 11B Ð 24-V Safety Circuit Wiring (080-110 and Associated Modular Units)

The voltage supplied to the processor is polarized. When checking for proper voltage supply, be sure to consider this polarity. If voltage appears to be within acceptable toler- ance, check to be sure the transformer supplying PS1 is not grounded. Grounding the supply transformer can result in serious damage to the control system.

Code 29 LOCAL/ENABLE-STOP-CCN Switch Failure (switch resistances out of range) (alarm)

This fault occurs due to the failure of the switch or due to a wiring error.

Code 30 Reset input failure (4 to 20 mA) (alert)

Code 31 Demand limit input failure (4 to 20 mA) (alert)

These codes apply only if unit is con®gured for these func- tions. If 4 to 20 mA signal is less than 4 or more than 20 mA, reset or demand limit function is disabled and unit functions normally. If mA signal returns to the acceptable range, function is automatically enabled.

Code 32 Loss of communication with compressor relay module (DISO-LV) (alarm)

Code 33 Loss of communication with EXV relay

module (DSIO-EXV) (alarm)

If communication is lost with either of these modules, unit shuts down without pumpout. This alarm resets automati- cally when communication is restored. The unit starts up nor- mally after alarm condition is reset. Probable cause of con- dition is a faulty or improperly connected plug, wiring error, or faulty module.

Loss of communication can be attributed to a grounded transformer with a secondary voltage of 21 vac supplying the PSIO, DSIO-LV, or 4 IN/4 OUT modules; the 12.5-vac transformer supplying the DSIO-EXV module; or the 24-vac transformer supplying PS1 for the transformers. These transformers should not be grounded, or serious damage to controls can result. Check to be sure the transformers are not grounded.

NOTE: If a blank PSIO module is downloaded without be- ing connected to the modules DSIO, this alarm is energized.

Code 34 Loss of communication with 4 In/4 Out module (alarm)

This applies only if one or more of the following options are used:

·external temperature reset

·4 to 20 mA temperature reset

·external switch controlled dual set point

·switch controlled demand limit

·4 to 20 mA demand limit

·hot gas bypass

If communication is lost with 4 IN/4 OUT module, the unit shuts off automatically, after ®nishing pumpout. Reset of alarm is automatic when communication is restored. Start-up after alarm is remedied follows a normal sequence. Probable cause of condition is a faulty or improperly connected plug, wiring error, or faulty module.

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