Carrier 50ZH024-060 instruction manual Cooling, Heat Pump Heating

		LEGEND
FLA	—	Full Load Amps
LRA	—	Locked Rotor Amps	®
MCA	—	Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
RLA	—	Rated Load Amps
CKT BKR — Circuit Breaker

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

=100 x max voltage deviation from average voltage average voltage

758110

683100

(KILOPASCALS)PRESSURELINESUCTION		(PSIG)PRESSURELINESUCTION		OUTDOOR TEMP
				OF	OC
	621		90	115	46
				105	41
				95	35
	552		80	85	29
				75	24
				65	18
				55	13
	483		70	45	7
	414		60
	345		50
	276		40
	207		30

30	40	50	60	70	80	90
	SUCTION LINE TEMPERATURE (OF)
-1	4	10	16	21	27	32
	SUCTION LINE TEMPERATURE (OC)

C00162

Fig. 16ÐCooling Charging Chart, 50ZH024 Units

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.

EXAMPLE: Supply voltage is 460-3-60.

AB = 452 v BC = 464 v AC = 455 v

Average Voltage = 452 + 464 + 455 3

= 1371

3 = 457

Determine maximum deviation from average voltage. (AB) 457 452 = 5 v

(BC) 464 457 = 7 v (AC) 457 455 = 2 v

Maximum deviation is 7 v.

Determine percent of voltage imbalance.

% Voltage Imbalance = 100 x		7
	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.

									C99024
	758	110
	683	100						OUTDOOR TEMP
SUCTION LINE PRESSURE (KILOPASCALS)								OF	OC
								115	46
	621	SUCTION LINE PRESSURE (PSIG)	90
								105	41
	552		80					95	35
								85	29
								75	24
	483		70					65	18
								55	13
	414		60
								45	7
	345		50
	276		40
	207		30
			30	40	50	60	70	80	90

SUCTION LINE TEMPERATURE (OF)

-1	4	10	16	21	27	32
	SUCTION LINE TEMPERATURE (OC)

Fig. 17ÐCooling Charging Chart, 50ZH030C00163

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

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