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 released to the
ambient air through the drain tube or the condensate evaporator.
The heat removed through the evaporator coil is transferred by the compressed refrigerant to the condenser coil.
Ambient air or water is then passed through the condenser coil, where it absorbs the heat and is then discharged to
the environment.
The EPR (Evaporator Pressure Regulator) valve prevents the evaporator coil from freezing by reducing the cooling
capacity of the air conditioner. The unit is also equipped with a Low Temperature Thermostat to prevent the evaporator
coil from freezing. 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).
REFRIGERANT
FILTER DRYER
CONTROL
BYPASS VALVE
METERING
DEVICE
(Capillary Tube Shown)
COMPRESSOR
EVAPORATOR
HEAT EXCHANGER
CONDENSER
AIR INLET
(Ambient Air In)
CONDENSER
HEAT EXCHANGER
CONDENSER OUTLET
(Heated Ambient Air Out)
HEATED AIR
FROM ENCLOSURE
CONDENSER
AIR INLET
(Ambient Air In)
ACCUMULATOR
COOL AIR
TO ENCLOSURE
13NP47
5
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.
