Event electronic K_NA4C3P21R - Manual (Page 5)

V. Principles of Operation
Kooltronic Air Conditioners are required when the equipment operating temperature must be kept near or
lower than the ambient room temperature, and/or the cabinet must be sealed from dust, fumes, oil,
corrosives and other contaminants. These Air Conditioners utilize a "Closed-Loop Cooling System" to ensure
optimum performance of the installed components.
Closed-Loop cooling seals the electronic enclosure from hostile elements in the
environment. Two separate circulation systems are employed. The internal
system cools and dehumidifies the air inside the cabinet, totally isolating the
sensitive electronics and other components from the environment. The external
system uses circulating ambient air or water to discharge the heat removed from
the electronics. The heat is dissipated from the enclosure by means of the vapor
compression refrigeration cycle. This takes place in a hermetically-sealed
refrigeration system, utilizing either an air-cooled or water-cooled condenser
heat exchanger. The warm air inside the enclosure is drawn through the
evaporator coil where it is cooled, dehumidified and returned.
Any enclosure moisture accumulated on the evaporator coil is collected in the
condensate tray and removed through the drain tube to the condensate
evaporator. Condensate evaporates in the condensate evaporator and is
released to the ambient air by the condenser impeller.
The heat removed through the evaporator coil is transferred by the compressed
refrigerant to the condenser coil. Ambient air is then passed through the
condenser coil, where it absorbs the heat and is then discharged to the
environment.
Kooltronic Air Conditioners are designed to operate continuously in order to
eliminate compressor cycling, which shortens compressor life and causes line
transients. This unit is also equipped with a Low Temperature Thermostat to
prevent the evaporator coil from freezing. In conditions of low ambient
temperature and low enclosure load, the thermostat regulates the return air
temperature from 75°F to 86°F. The standard set point of the Low Temperature
Thermostat is 75°F. The set point can be changed to 70°F or to 79°F by
changing the location of the thermostat jumper (See illustration at right).
The Low Temperature Thermostat has a test start relay. When the air conditioner is turned on it will run
constantly for the first 15 minutes regardless of external temperatures. Afterwards, if the entering evaporator
air temperature is lower than the thermostat set point, the compressor and condenser blower will stop, and
the thermostat will begin to control the air conditioner.
CONDENSER
HEAT EXCHANGER
EVAPORATOR
HEAT EXCHANGER
HEATED AIR
FROM ENCLOSURE
COOL AIR
TO ENCLOSURE
CONDENSER OUTLET
(Heated Ambient Air Out)
(2 Places)
CONDENSER AIR
INLET
(Ambient Air In)
COMPRESSOR
5
3
2 1 4
70ºF - Connect 1 and 2
75ºF - Connect 1 and 3
79ºF - Connect 1 and 4
Thermostat Jumper
P21