Carrier 50ZH024-060 Fig. 16Cooling Charging Chart, 50ZH024 Units, Fig. 17Cooling Charging Chart, 50ZH030

NOTE: Some units are equipped with a time-delay relay. On

these units, the indoor fan remains on for 30 seconds after G or Y

is deenergized.

COOLING

With the thermostat subbase in the cooling position, the thermostat

makes circuit R-O. This energizes the reversing valve solenoid

(RVS) and places the unit in standby condition for cooling.

NOTE: The defrost control board has a 5 minute compressor

anti-short cycle time delay built in between compressor starts.

On a call for cooling, the compressor contactor (C) and the IFR are

energized through the Y and G terminals of the thermostat.

Energizing the compressor contactor supplies power to the com-

pressor and the outdoor (condenser) fan motor (OFM). Energizing

the IFR provides power to the IFM.

When the need for cooling has been satisfied, the OFM, compres-

sor, and IFM (FAN on AUTO) are deenergized. If the unit is

equipped with a 30-second delay (036 size only), the indoor fan

will remain energized for 30 seconds after the compressor is

deenergized. The reversing valve solenoid remains energized.

HEAT PUMP HEATING

On a call for heat, thermostat makes circuits R-Y and R-G. When

compressor time delay (5-minute ± 2 minutes) is completed, a

circuit is made to C, starting COMP and OFM. Circuit R-G also

energizes IFR and starts IFM after 1-second delay.

Should room temperature continue to fall, circuit R-W is made

through second-stage thermostat bulb. If optional electric heat

package is used, a relay is energized, bringing on first bank of

C99024

452=5v

457=7v

455=2v

LEGEND

FLA — Full Load Amps

LRA — Locked Rotor Amps

MCA — Minimum Circuit Amps

MOCP — Maximum Overcurrent Protection

RLA — Rated Load Amps

NOTES:

1. In compliance with NEC (National Electrical Code) requirements

for multimotor and combination load equipment (refer to NEC

Articles 430 and 440), the overcurrent protective device for the

unit shall be Power Supply fuse. Canadian units may be

fuse or circuit breaker.

2. Minimum wire size is based on 60 C copper wire. If other than

60 C wire is used, or if length exceeds wire length in table,

determine size from NEC.

3. Unbalanced 3-Phase Supply Voltage

Never operate a motor where a phase imbalance in supply volt-

age is greater than 2%.

Use the following formula to determine

the percentage of voltage imbalance.

% Voltage imbalance

max voltage deviation from average voltage

= 100 x average voltage

EXAMPLE: Supply voltage is 460-3-60.

AB = 452 v

BC = 464 v

AC = 455 v 452 + 464 + 455

Average Voltage = 3

1371

= 457

Determine maximum deviation from average voltage.

(AB) 457

(BC) 464

(AC) 457

Maximum deviation is 7 v.

Determine percent of voltage imbalance.

% Voltage Imbalance = 100 x 457

= 1.53%

This amount of phase imbalance is satisfactory as it is below the

maximum allowable 2%.

IMPORTANT: If the supply voltage phase imbalance is

more than 2%, contact your local electric utility company

immediately.

CKT BKR —Circuit Breaker

758 110

683 100

621 90

552 80

483 70

414 60

345 50

276 40

207 30

30 40 50 60 70 80 90

-1 4 1016212732

SUCTION LINE TEMPERATURE (OF)

SUCTION LINE TEMPERATURE (OC)

OUTDOOR TEMP

OFOC

115 46

105 41

95 35

85 29

75 24

65 18

55 13

45 7

SUCTION LINE PRESSURE (KILOPASCALS)

SUCTION LINE PRESSURE (PSIG)

C00162

Fig. 16—Cooling Charging Chart, 50ZH024 Units