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.
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 60°F. When the entering evaporator air temperature rises above 60°F the heater shuts off, and
when the evaporator air temperature falls below 40°F the heater will engage. The contact points of the alarm thermostat are
normally closed. If the entering evaporator air temperature exceeds 130°F the alarm thermostat contacts open, and when the
temperature drops below 130°F 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 95°F the condenser fan will run at full speed. When the ambient
temperature is between 85°F and 95°F the condenser fan will run between maximum and minimum speed. When the ambient
temperature is lower than 85°F 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 75°F to 115°F enclosure
temperature, depending on the ambient temperatures.
N.O.
