Desert Aire LW, Installation And Operation Manual

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3.2.3 Evaporator Defrost Mode
Under normal conditions, evaporating temperatures may fall below 32°F
causing frost to form on the coil. A timer within the unit’s controller will initiate
the defrost cycle as needed. The defrost cycle is terminated automatically
when the coil is cleared of frost. During a defrost cycle, there is little difference
between the dehumidifier’s entering and leaving air conditions.
3.2.3.1 Defrost Cycle Settings
The LW series dehumidifier is factory set to run a defrost cycle at 15
timed cycles that are initiated with an evaporating temperature below
30°F. The delay between cycles is set at 30 minutes. The cycle
terminated upon temperature rise to 40°F. If your application includes
ambient temperatures above 50°F, you will improve system
performance by resetting the defrost timer. Monitor system
performance to determine an optimal setting for your application.
Do not deviate from factory settings unless you monitor the system closely!
3.2.4 Pump Down Cycle
LW series dehumidifiers are factory wired for “pump down.” This effectively
reduces the likelihood of liquid refrigeration build-up in the low side of the
system during the off cycle. Whenever there is power to the unit, the
compressor will become energized if suction pressure rises above 40 psig and
will run until it drops below 10 psig. Typically, this occurs during the off cycle
with an average compressor run time of about 10 minutes.
3.2.5 Blower Operation
LW series dehumidifiers are designed for commercial use and consequently
are wired for continuous blower operation. This helps prevent the cycling of
the unit due to false loads created by air stagnation and stratification. This is
especially true in ice rink applications. However, if your application includes
cycling the blower, you can accomplish this by changing the blower controller
setup to “Automatic” operation.
Desert Aire - LW Manual