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 75oF to 86oF. The
standard set point of the Low Temperature Thermostat is 75oF. The set point can be changed to 70oF or to 79oF 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.
The heater kit consists of a heater, a heat control thermostat and a heater limiter. The heater control thermostat is a bimetal disk
with a fixed set point of 60oF. When the entering evaporator air temperature rises above 60oF the heater shuts off, and when the
evaporator air temperature falls below 40oF the heater will engage. The contact points of the alarm thermostat are normally
closed. If the entering evaporator air temperature exceeds 130oF the alarm thermostat contacts open, and when the temperature
drops below 130oF the contacts close.
A condenser fan speed controller is standard on this unit. The speed controller temperature sensor is installed in the airstream
of the condenser. When the ambient temperature is above 95oF the condenser fan will run at full speed. When the ambient
temperature is between 85oF and 95oF the condenser fan will run between maximum and minimum speed. When the ambient
temperature is lower than 85oF the condenser fan will cycle. In applications having frequent voluntary heat load fluctuations, an
optional Short Cycle Protector is recommended.
When the Kooltronic Air Conditioner is properly sized it should operate constantly and maintain 75oF to 115oF enclosure
temperature, depending on the ambient temperatures.
N.O.
