For 460-V Motors, ÐUnit Controls | Carrier 50ZH024-060 specification

C	BRN (COMMON)
C	VIO (STEP 2)
W1	VIO (STEP 2)
W1	WHT ( STEP 1)
W1	WHT ( STEP 1)
W1
TO	BLK	CONTACTOR 2
TO	YEL		BRN
UNIT POWER	YEL		BRN
WIRING		YEL	YEL

	FUSE BLOCK			CONTACTOR 1
	F3	YEL		BRN
L2	F4	YEL	YEL	YEL
L2

F1 BLK

YEL

F2 BLK

Fig. 15BÐAccessory Electric Heater Wiring

EL 1

EL 2

EL 3

AUTO-LIMIT BLK

BLK

C00014

NOTE: Be sure that all supply- and return-air grilles are open, free from obstructions, and adjusted properly.

Disconnect electrical power to the unit and install lockout tag before changing blower speed. Electrical shock can cause serious injury or death.

Airflow can be changed by changing the lead connections of the blower motor.

Units 50ZH024, 036, 048, and 060 blower motors are factory wired for low speed operation. Units 50ZH030 and 042 are factory wired for medium speed operation.

FOR 208/230-V

The motor leads are color-coded as follows:

3-SPEED	2-SPEED
black = high speed	black = high speed
blue = medium speed	-
red = low speed	red = low speed

To change the speed of the indoor fan motor (IFM), remove the fan motor speed leg lead from the indoor fan relay (IFR) with units 024, 030, 042, 048 & 060 or the time delay relay (TDR) on 036 size and replace with lead for desired blower motor speed. Insulate the removed lead to avoid contact with chassis parts.

FOR 460-V MOTORS

The motor leads are color coded as follows:

3-SPEED (060 ONLY)	2-SPEED
black = high speed	black = to purple
-	yellow = line
orange = medium speed	purple = to black
blue = low speed	red = line

To change the speed of the indoor fan motor (IFM) from low speed to high speed, remove the red lead from the indoor-fan relay (IFR). ON 2±Speed Motors: Insulate the red lead to avoid contact with any chassis parts. Separate the black lead from the purple lead.

Connect the black lead to the IFR. Insulate the purple lead to avoid contact with any chassis parts. ON 3±Speed Motors: remove the fan motor speed leg lead from the indoor (indoor) fan relay (IFR) and replace with lead for desired blower motor speed.

Step 5ÐUnit Controls

All compressors have the following internal-protection controls.

HIGH-PRESSURE RELIEF VALVE

This valve opens when the pressure differential between the low and high side becomes excessive (024 size has temperature relief only).

LOSS OF CHARGE SWITCH

Located on the outdoor liquid line is a low-pressure switch which functions as a loss-of-charge switch. This switch contains a Schrader core depressor. This switch opens at 7 psig and closes at 22 psig. No adjustment is necessary.

COMPRESSOR OVERLOAD

This overload interrupts power to the compressor when either the current or internal temperature become excessive, and automati- cally resets when the internal temperature drops to a safe level. This overload may require up to 60 minutes (or longer) to reset; therefore, if the internal overload is suspected of being open, disconnect the electrical power to the unit and check the circuit through the overload with an ohmmeter or continuity tester.

Step 6ÐSequence of Operation

FAN OPERATION

The FAN switch on the thermostat controls indoor fan operation. When the FAN switch is placed in the ON position, the IFR (indoor-fan relay) is energized through the G terminal on the thermostat. The normally-open contacts close, which then provide power to the indoor (evaporator) fan motor (IFM). The IFM will run continuously when the FAN switch is set to ON.

When the FAN switch is set to AUTO, the thermostat deenergizes the IFR (provided there is not a call for cooling). The contacts open and the IFM is deenergized. The IFM will be energized only when there is a call for cooling, in heat pump heating mode or if the unit is equipped with accessory electric heat, the indoor-fan motor will also run while the accessory electric heat is energized.