Carrier 50RTG specifications Refrigerant Charging, Air Coil Fan Motor Removal, Troubleshooting

FILL CONDENSER WITH
CLEANING SOLUTION. DO	PAIL
NOT ADD SOLUTION
MORE RAPIDLY THAN
VENT CAN EXHAUST
GASES CAUSED BY	FUNNEL
CHEMICAL ACTION.
	1”
	PIPE
VENT
PIPE	5’ APPROX

3’ TO 4’

CONDENSER

PAIL

Fig. 8 — Gravity Flow Method

PUMP	PRIMING	GAS VENT
	CONN.	GLOBE
		VALVES
SUCTION
PUMP		SUPPLY
SUPPORT		1” PIPE
		CONDENSER
TANK		REMOVE WATER
		REGULATING VALVE
FINE MESH		RETURN
SCREEN

Fig. 9 — Forced Circulation Method

Checking System Charge — Units are shipped with full operating charge. If recharging is necessary:

1.Insert thermometer bulb in insulating rubber sleeve on liquid line near filter drier. Use a digital thermometer for all temperature measurements. DO NOT use a mercury or dial-type thermometer.

2.Connect pressure gage to discharge line near compressor.

3.After unit conditions have stabilized, read head pressure on discharge line gage.

NOTE: Operate unit a minimum of 15 minutes before checking charge.

4.From standard field-supplied Pressure-Temperature chart for R-22, find equivalent saturated condensing temperature.

5.Read liquid line temperature on thermometer; then subtract from saturated condensing temperature. The dif- ference equals subcooling temperature.

6.ADD refrigerant to raise the temperature or REMOVE refrigerant (using standard practices) to lower the temper- ature (allow a tolerance of ± 3° F), as required.

Refrigerant Charging

To prevent personal injury, wear safety glasses and gloves when handling refrigerant. Do not overcharge system — this can cause compressor flooding.

NOTE: Do not vent or depressurize unit refrigerant to atmo- sphere. Remove and reclaim refrigerant following accepted practices.

Air Coil Fan Motor Removal

Before attempting to remove fan motors or motor mounts, place a piece of plywood over evaporator coils to prevent coil damage.

Motor power wires need to be disconnected from motor terminals before motor is removed from unit.

1.Shut off unit main power supply.

2.Loosen bolts on mounting bracket so that fan belt can be removed.

3.Loosen and remove the 2 motor mounting bracket bolts on left side of bracket.

4.Slide motor/bracket assembly to extreme right and lift out through space between fan scroll and side frame. Rest motor on a high platform such as a step ladder. Do not allow motor to hang by its power wires.

TROUBLESHOOTING

(Fig. 10 and 11, and Table 22)

When troubleshooting problems with a WSHP, consider the following.

Thermistor — A thermistor may be required for single- phase units where starting the unit is a problem due to low voltage. See Fig. 10 for thermistor nominal resistance.

Control Sensors — The control system employs 2 nom- inal 10,000 ohm thermistors (FP1 and FP2) that are used for freeze protection. Be sure FP1 is located in the discharge fluid and FP2 is located in the air discharge. See Fig. 11.

	90.0
	80.0
	70.0
(kOhm)	60.0
	50.0
Resistance
	40.0
	30.0
	20.0
	10.0
	0.0
	0.0	20.0	40.0	60.0	80.0	100.0	120.0	140.0
				Temperature (F)

Fig. 10 — Thermistor Nominal Resistance

22