5
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.
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.
FRONT PANEL COMMANDS
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.
AMBIENT
AIR IN
CONDENSER
AIR OUT
SUPPLY
AIR OUT
RETURN
AIR IN
PROGRAMMABLE
THERMOSTAT
NP17L
