Carrier Aquazone 50HQP Series Installation, Start-Up And Service Instructions Manual page 44

FORCED CIRCULATION METHOD
Fully open vent pipe when filling condenser. The vent may be
closed when condenser is full and pump is operating. See Fig. 34.
Regulate flow to condenser with a supply line valve. If pump is a
non-overloading type, the valve may be fully closed while pump
is running.
For average scale deposit, allow solution to remain in condenser
overnight. For heavy scale deposit, allow 24 hours. Drain con-
denser and flush with clean water. Follow acid manufacturer's
instructions.
PUMP
PRIMING
CONN.
SUCTION
PUMP
SUPPORT
TANK
FINE MESH
SCREEN
Fig. 34 — 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 liq-
uid 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 check-
ing charge.
4. From standard field-supplied Pressure-Temperature chart
for R-410A, find equivalent saturated condensing
temperature.
5. Read liquid line temperature on thermometer; then
subtract from saturated condensing temperature. The dif-
ference equals subcooling temperature.
Refrigerant Charging
WARNING
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 atmosphere.
Remove and recover refrigerant following accepted practices.
GAS VENT
GLOBE
VALVES
SUPPLY
1" PIPE
CONDENSER
REMOVE WATER
REGULATING VALVE
RETURN
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 termi-
nals 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
When troubleshooting problems with a WSHP, consider the fol-
lowing and see Table 9:
Thermistor
A thermistor may be required for single-phase units where starting
the unit is a problem due to low voltage. See Fig. 35 for thermistor
nominal resistance.
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
0.0 20.0 40.0
Fig. 35 — Thermistor Nominal Resistance
44
CAUTION
60.0 80.0 100.0 120.0
Temperature (degF)
140.0