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.
This unit is 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 illustrations below).
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
P21
2.06
[52.3]
.17
[4.3]
2.60
[66.0]
2
1
1
2
4
3
J2
3
4
5
10
9
8
7
6
1
2
3
J1
CG
RELAY
CONTACTS
N.O.
240 VAC
120 VAC
TEMPERATURE
SENSOR
Mounting Holes (4)
.156 [3.9] DIA.
ADJUSTING
PINS
3
2
1
4
70ºF - Connect 1 and 2
75ºF - Connect 1 and 3
79ºF - Connect 1 and 4
Thermostat Jumper
ELECTRONIC
THERMOSTAT
CONTROL
Electronic Thermostat Control
Dimensions, inches [mm], are for reference only
and are subject to change.
