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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.
Priming
Pump
Conn.
Suction
Pump
Support
Tank
Fine Mesh
Screen
Fig. 42 — Forced Circulation Method
For average scale deposit, allow solution to remain in condenser
overnight. For heavy scale deposit, allow 24 hours. Drain
condenser and flush with clean water. Follow acid
manufacturer's instructions.
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
dialtype thermometer.
2.
Connect pressure gauge to discharge line near compressor.
3.
After unit conditions have stabilized, read head pressure on
discharge line gauge.
NOTE: Operate unit a minimum of 15 minutes before checking
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 difference
equals subcooling temperature.
6.
Compare the subcooling temperature with the normal
temperature listed in Tables 19-31. If the measured liquid line
Gas Vent
Globe
Va lves
Supply
1" Pipe
Condenser
Remove Wa ter
Regulating Va lve
Return
temperature does not agree with the required liquid line
temperature, ADD refrigerant to raise the temperature or
REMOVE refrigerant (using standard practices) to lower the
temperature (allow a tolerance of ± 3°F).
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 atmosphere.
Remove and recover 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.
Disconnect motor power wires from motor terminals before motor
is removed from unit.
1.
Shut off unit main power supply and apply lock-out/tag-out.
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
following.
UNIT PROTECTION MODULE (UPM)
Each unit is factory provided with a UPM board that controls the
compressor operation and monitors the safeties. The UPM board
should be one of the first areas to start with troubleshooting an
equipment issue. See Fig. 43.
57
WARNING
CAUTION
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