Chapter 6 Maintenance 49
DataMate 3000 Series Air Conditioner User Manual
6.2.3 Drain Line
Inspect the humidifier tray periodically for proper function of the drain line. Ensure
that there is no foreign matter or leak in the drain line.
6.2.4 Heater
If the optional heater is used, maintain it periodically to ensure that no dust or
foreign matter collects on its surface, the heater is fixed solidly and its cable
connection is reliable.
The heater generates heat continuously in normal situation. Inspect the heater
every six months for its normal operation.
6.2.5 Thermal Expansion Valve
The thermal expansion valve keeps the evaporator supplied with enough refrigerant
to satisfy load conditions. Measure the superheat level to determine if the valve
operation is proper. The correct superheat setting is 5.6°C to 8.3°C (10°F to 15°F).
6.2.6 High/Low Pressure Switch
The discharge pressure and suction pressure will vary greatly with load and
ambient conditions (refer to Table 6-1) during normal operation. The high-pressure
switch will be activated and send an alarm signal to the controller when the
discharge pressure reaches to the high-pressure setpoint. Then the controller will
shut down the compressor.
If the suction pressure is lower than the low-pressure setpoint, the low-pressure
switch will activate and then the controller will shut down the cooling system.
Table 6-1 Typical discharge pressure/suction pressure
PSIG
MPa
Low pressure
57.5~99.8
0.397~0.67
Low-pressure setting
15.7
0.1
Low-pressure recovery point
57.5
0.4
High pressure
180~275
1.242~1.895
High-pressure setting
400
2.76
High-pressure recovery point 307
2.1
