Carrier 48TC 04 Series Service And Maintenance Instructions page 19

For Pressure Transducer wiring. Replace and secure the
controller cover. Check for clearances around the blower
and belt. Restore power to the unit.
Charge check and adjustment
Accurate pressure gauge and temperature sensing meter
are required. Connect the pressure gauge to the service
port on the discharge line. Mount the temperature sensing
device on the liquid line leaving the outdoor coil and
insulate it so that outdoor ambient temperature does not
affect the reading.
Adjust the humidistat setting to highest setpoint possible
(no demand). Start/run the unit in base Cooling mode.
Check and adjust unit charge for each circuit.
When the test operating conditions for suction line
temperature and suction pressure coincide with the current
ambient temperature line, switch the unit to Reheat1 mode
by adjusting the humidistat setting to a low setpoint.
Check that each circuit's CLV is energized and valves are
closed. After five minutes of operation in Reheat1 mode,
return to Cooling mode by readjusting the humidistat
setting to high. Recheck each circuit's charge condition;
re- - adjust charge if necessary.
When charging procedure is completed, remove the
bypass wiring on the Motormaster control. Readjust the
cooling thermostat setting and the humidistat setting to
appropriate design setpoints.
Size E16
Unit size E16 (two circuit design with TXVs) uses the
liquid temperature/discharge pressure charging method.
See Fig. 36 to determine the proper leaving condenser
liquid temperature at the test condition compressor
discharge pressure. During the charge adjustment step, the
unit will be run in the Cooling mode; thermostat will be in
Cool demand, humidistat will be open for no demand. The
standard Motormaster head pressure control device will be
bypassed to operate outdoor fan motors OFM1 and OFM2
at full speed. If outdoor temperature is low (causing Low
Ambient Staging switch LAS to open), a jumper will be
required to energize OFM3.
Accurate pressure gauge and temperature sensing meter
are required for each circuit. Connect the pressure gauge
to the service port on the discharge line. Mount the
temperature sensing device on the liquid line leaving the
outdoor coil and insulate it so that outdoor ambient
temperature does not affect the reading. Confirm the
location of Circuit 1 and Circuit 2 tube locations.
Example (Fig. 36):
Unit E16 Circuit 1
Compressor Discharge Pressure . . 350 psig (2415 kPA)
Leaving Condenser Liquid Temperature . . 95F (34.4C)
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