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Refrigerant charging, Air coil fan motor removal, Thermistor – Carrier AQUAZONE RVC User Manual

Page 40: Control sensors

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40

Refrigerant Charging

NOTE: Do not vent or depressurize unit refrigerant to

atmosphere. Remove and reclaim refrigerant following

accepted practices.

Air Coil Fan Motor Removal

Disconnect motor power wires 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. 31 and 32, and Table 30)

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. 31 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. 32.

To prevent personal injury, wear safety glasses and gloves

when handling refrigerant. Do not overcharge system —

this can cause compressor flooding.

Before attempting to remove fan motors or motor mounts,

place a piece of plywood over evaporator coils to prevent

coil damage.

a50-8163

SUCTION

COMPRESSOR

DISCHARGE

COAX

EXPANSION

VALVE

FP2

FP1

LIQUID
LINE

WATER IN

WATER OUT

CONDENSATE

OVERFLOW

(CO)

AIR COIL
FREEZE
PROTECTION

WATER
COIL
PROTECTION

THERMISTOR

(

°F)

(

°F)

AIR

COIL

AIRFLOW

AIRFLOW

LEGEND

Fig. 32 — FP1 and FP2 Thermistor Location

COAX — Coaxial Heat Exchanger

Airflow
Refrigerant Liquid Line Flow

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

Temperature (degF)

Resistance (kOhm)

Fig. 31 — Thermistor Nominal Resistance

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