Principles of Operation (con’t)
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.
Temperature on the thermostat display is 5°F higher than the return temperature from the enclosure. The low
temperature thermostat set point is 80°F. The set point can be adjusted. Consult with Kooltronic if the set point
needs to be adjusted below 80°F.
The optional heater 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 heater limiter features a manual reset. This unit is
equipped with a Temperature Alarm, which has normally-closed and normally open contacts, and a set point of 115°F. This unit
is equipped with a high pressure switch. When abnormal conditions are detected, the switch shuts off the compressor. 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.
CONTROL ACTION
The evaporator blower operates continuously. The compressor is cycled on and off by the action from the factory preset
programmable thermostat. A pressure switch controls the on/off action of the condenser blower.
The regulation is performed according to the temperature measured by the thermostat probe with a positive differential from the
set point: if the temperature increases and reaches set point plus differential the compressor is started and then turned off when
the temperature reaches the set point value again.
In case of fault in the thermostat probe the start and stop of the compressor are
timed through preset parameters.
The programmable thermostat is located as shown in the upper right ISO
illustration. WARNING: the programmable device is preprogrammed and set at the
factory. In the event changes are needed the following instructions can be used.
PROGRAMMABLE
THERMOSTAT
CONDENSER
AIR OUT
(TWO PLACES)
CONDENSER
AIR IN
RETURN
AIR IN
SUPPLY
AIR OUT
7
HL48LV
FRONT PANEL LED INDICATORS
- To display target set point; in programming mode it selects a parameter or confirms an operation.
(UP)
- To see the max. stored temperature; in programming mode it browses the parameter codes or increases the displayed value.
(DOWN)
- To see the min. stored temperature; in programming mode it browses the parameter codes or decreases the displayed value.
- To switch the instrument off, if onF = oFF.
- Not enabled.
(DEF)
- To start a manual defrost.
KEY COMBINATIONS
To lock and unlock the keyboard.
To return to the room temperature display.
To enter programming mode.
FRONT PANEL COMMANDS
