Carrier 50SX024-060, 50SS018-060 Terminal, Mode FAN Cooling Heating, Option Description

INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS

For cooling operation, the recommended air¯ow is 350 to 450 cfm per each 12,000 Btuh of rated cooling capacity.

Tables 8-11 show air¯ows at several external static pres- sures. Table 12 shows air¯ow for Fan Only and Cooling modes for ICM units. Tables 13-15 show accompanying pressure drops for wet coils, electric heaters, and ®lters. Refer to these tables to determine the air¯ow for the system being installed.

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

Disconnect electrical power to the unit before changing blower speed. Electrical shock can cause personal in- jury or death.

Air¯ow can be changed by changing the lead connections of the blower motor.

Unit 50SS two- or 3-speed motors are factory wired for low speed operation. Units 50SX024, 036 and 048 (460 v) two- or 3-speed motors are factory wired for low speed. Units 50SX030 and 042 are factory wired for medium speed.

For 208/230-v and A.O. Smith 460-v Blower Motors:

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 blower motor, remove the fan motor speed leg lead from the indoor (evaporator) fan relay (IFR) and replace with lead for desired blower motor speed. Insulate the removed lead to avoid contact with chassis parts.

For 460-v GE Motors:

The motor leads are color coded as follows:

3-SPEED		2-SPEED
black	= high	black	=	high
blue	= jumper	blue	=	jumper
orange = medium		red	= low
red	= low

To change the speed of the blower motor, remove red fan motor speed lead from the indoor (evaporator) fan relay (IFR). The motor speed lead is attached to terminal BM. Insulate removed lead end to avoid contact with chassis parts. On 3-speed motors only, connect orange lead to IFR. To select high speed, separate the black (female QC) from the blue lead (male QC) and connect the black lead to IFR. Insulate the blue lead to avoid contact with any chassis parts.

For Integrated Control Motors (ICM) Ð To con®gure the 50SX unit, move the 5 Easy Select board wires to the terminals which control the air¯ow. Refer to the Easy Select interface board (Fig. 32) located next to the terminal and to Fig. 33 and 34.

Perform the following steps for basic system con®guration.

AUX HEAT RANGE (VIO)

NOTE: If no heater is installed, this step can be omitted.

The air¯ow for electric heat is selected with the AUX HEAT RANGE terminals. Refer to Table 3 and the installation in- structions for electric heaters for minimum air¯ow required for safe heater operation. Refer to table below for the avail- able air¯ows. Each select pin is con®gured for a certain air- ¯ow. The air¯ow will be supplied in the Heating mode on air conditioners when electric heat is the primary heating source. The preset factory default selection is the highest air¯ow.

TERMINAL	1	2	3	4
Available	1365	1470	1680	1840
Air¯ow (Cfm)

AC/HP SIZE (BLU) Ð The preset factory default selection for AC/HP SIZE (air conditioner/heat pump) is set to 400 cfm/ton. The selection pins are con®gured for 350 cfm/ ton and 400 cfm/ton.

TYPE (ORN) Ð The TYPE is a preset factory default se- lection. The preset factory default setting is AC for the 50SX units. Default setting should not be altered.

AC/HP CFM ADJUST (BLK) Ð The preset factory default selection is MED. Selections HI and LO will adjust the air- ¯ow supplied for all operational modes (see table below). The selection options allow installer to adjust air¯ow to meet such individual needs as noise and static compensation, etc.

MODE	FAN	COOLING	HEATING
	ONLY
LO - Adjust	−15%	−10%	−10%
HI - Adjust	15%	10%	10%

AC/HP TIME DELAY (GRY) Ð Four motor operation delay options are provided to customize system operation. See list- ing below:

OPTION	DESCRIPTION
30-Sec On/60-Sec	Used when it is desirable to allow system
Off Delay	coils time to heat up or cool down prior to
Pro®le (Terminal 1)	air¯ow.
No Delay Option	Used for servicing or when other compo-
	nents are used to perform the delay
(Terminal 2)
	function.
30-Sec Off Delay	Preset factory default setting for 50SX
(Terminal 3)	units.
45-Sec Off Delay	Enhances system efficiency.
(Terminal 4)

UNIT CONTROLS Ð All compressors have the following internal-protection controls.

High-Pressure Relief Valve Ð This valve opens when the pressure differential between the low and high side becomes excessive.

Compressor Overload Ð This overload interrupts power to the compressor when either the current or internal tempera- ture become excessive, and automatically 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 con- tinuity tester.

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