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 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 an air-cooled condenser heat exchanger. The warm air inside the enclosure
is drawn through the evaporator coil where it is cooled, dehumidified and returned.
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.
A condenser fan speed controller is standard on this unit. The condenser fan will run at full speed, or will be off, depending on
ambient conditions. The crankcase compressor heater allows the unit to start with an ambient temperature of 0°F. 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 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.
When the Kooltronic Air Conditioner is properly sized it should operate constantly and maintain 75°F to 115°F enclosure
temperature, depending on the ambient temperatures.
ENCLOSURE AIR
OUT
CONDENSER AIR
IN (3 PLACES)
ENCLOSURE AIR
IN
CONDENSER AIR
OUT
AIR IN
AIR OUT
EP62R
5
COOLING A/C MODE
ECONOMIZER MODE
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.
