Carrier AQUAZONE 50PTH - Manual (Page 45)

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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-410A refrigerant, find equivalent saturated con-
densing temperature.
5. Read liquid line temperature on thermometer; then
subtract from saturated condensing temperature. The dif-
ference equals subcooling temperature.
6. Compare the subcooling temperature with the normal
temperature listed in Tables 20-23. If the measured liquid
line temperature does not agree with the required liquid
line temperature, ADD refrigerant to raise the tempera-
ture or REMOVE refrigerant (using standard practices) to
lower the temperature (allow a tolerance of ± 3° F).
Refrigerant Charging
NOTE: Do not vent or depressurize unit refrigerant to atmo-
sphere. Remove and recover 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.
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.
Replacing the WSHP Open Controller’s Bat-
tery —
The WSHP Open controller’s 10-year lithium
CR2032 battery provides a minimum of 10,000 hours of data
retention during power outages.
NOTE: Power must be ON to the WSHP Open controller
when replacing the battery, or the date, time and trend data will
be lost.
1. Remove the battery from the controller, making note of
the battery's polarity.
2. Insert the new battery, matching the battery's polarity
with the polarity indicated on the WSHP Open controller.
TROUBLESHOOTING
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. 37 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. 38.
Fig. 35 — Gravity Flow Method
FILL CONDENSER WITH
CLEANING SOLUTION. DO
NOT ADD SOLUTION
MORE RAPIDLY THAN
VENT CAN EXHAUST
GASES CAUSED BY
CHEMICAL ACTION.
PAIL
FUNNEL
CONDENSER
PAIL
3’ TO 4’
VENT
PIPE
5’ APPROX
1”
PIPE
SUCTION
PUMP
SUPPORT
TANK
FINE MESH
SCREEN RETURN
GAS VENT PUMP PRIMING
CONN.
GLOBE
VALVES
SUPPLY
1” PIPE
CONDENSER
REMOVE WATER
REGULATING VALVE
Fig. 36 — Forced Circulation Method
WARNING
To prevent personal injury, wear safety glasses and gloves
when handling refrigerant. Do not overcharge system —
this can cause compressor flooding.
CAUTION
Before attempting to remove fan motors or motor mounts,
place a piece of plywood over evaporator coils to prevent
coil damage.