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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.

UNITS EQUIPPED WITH PROGRAMMABLE THERMOSTAT 

For units equipped with Low Temperature Thermostat, see page 8.

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.

CONDENSER
AIR OUT 

 SUPPLY
 AIR OUT

 RETURN
 AIR IN

CONDENSER 
AIR INLET

PROGRAMMABLE
THERMOSTAT

NEMA DP24L

Summary of Contents for Guardian K3NA4C3DP24L

Page 1: ...IS MANUAL BE READ AND UNDERSTOOD THOROUGHLY KOOLTRONIC INC 30 Pennington Hopewell Road Pennington NJ 08534 609 466 3400 FAX 609 466 1114 www kooltronic com 900 039 73 10 21 CDR 20368 GUARDIAN SERIES K3NA4C3DP24L 480 Volt 1 PHASE Find additional information on this model at kooltronic com or use the Technical Documents QR code below Technical Documents ...

Page 2: ...ic model page of the Kooltronic website I Introduction Kooltronic Air Conditioners are designed to provide a cool dehumidified environment for your electronic components There are models to fit virtually all sizes and shapes of electronics enclosures in capacities ranging from 1 000 to 30 000 BTU H Our closed loop design also ensures that your components will not be exposed to hot dirty operating ...

Page 3: ...s prior to operating in order to allow the compressor oil to drain to the compressor sump area CAUTION 3 Before operating this unit all electrical wiring must be checked to assure the proper connection to the correct power source Minimum circuit ampacity should be at least 125 of the amperage found on the nameplate for the corresponding voltage Do not exceed the maximum fuse size found on the name...

Page 4: ... incorrect type or amount of refrigerant will adversely affect performance and may damage the unit r Make sure that these parameters are met Failure to do so may result in permanent damage to the unit ALL MOTORS ARE THERMALLY PROTECTED VIOLATES WARRANTY UNAUTHORIZED SERVICE OR MODIFICATION OUTDOOR USE COMPARTMENT ONLY NEMA EEMAC UL50 BY UNDERWRITERS LABORATORIES INC TYPE 1 SPECIAL PURPOSE AIR COND...

Page 5: ...n 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 UNITS EQUIPPED WITH PROGRAMMABLE THERMOSTAT For units equipped with Low Temperature Thermostat see page 8 CONTROL ACTION The evaporator blower operates continuously The compressor is cycled on and off by the action from the factory p...

Page 6: ...e the new set point value push the SET key again or wait 10 seconds HOW TO CHANGE A PARAMETER VALUE To change a parameter s value operate as follows 1 Enter the Programming mode by pressing the SET plus down arrow keys for 3 seconds the C or F LED starts blinking 6 2 Select the required parameter Press the SET key to display its value 3 Use up or down arrow keys to change its value 4 Press SET to ...

Page 7: ...ap code 7 0 65535 rEL Software release 0 rSE Real set point 0 onF on off key enabling ES PbC Kind of probe ntc Adr Serial address 1 1 247 HES Differential for energy saving 0 F 54 54 rrd Regulation restart with door open alarm y odc Compress status when open door no nPS Number of activation of pressure switch 15 0 15 did Digital input alarm delay 5 min 0 255 i1F Digital input configuration EAL i1P...

Page 8: ... 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 c...

Page 9: ...te the air conditioner for approximately ten 10 minutes During this period the evaporator fan should operate continuously and no unusual noise or vibration should be evident The condenser blower is controlled by a pressure switch and may not start for several minutes Depending on ambient conditions the condenser blower may cycle during the test The cool air discharged should be less than 70 F when...

Page 10: ...to page 11 for the location of all mounting holes and cutouts Make sure the cutouts don t interfere with components inside your cabinet Proper alignment of all air inlets and outlets is essential for optimum performance of the air conditioner All externally mounted air conditioners are fully gasketed to ensure proper sealing This seal is necessary to maintain the integrity of the closed loop syste...

Page 11: ...ct to change 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 LOW TEMPERATURE THERMOSTAT CONTROL Electronic Thermostat Control Dimensions inches mm are for reference only and are subject to c...

Page 12: ...04 26 4 12 00 304 8 1 55 39 4 4 26 108 2 HIGH VOLTAGE FIELD CONNECTION BOX 68 17 0 PROGRAMMABLE THERMOSTAT TEMPERATURE ALARM TERMINAL BLOCK Drawings and Dimensions con t Dimensions inches mm are for reference only and are subject to change K3NA4C3DP24L LV FILTERED CONDENSER AIR INLET Ambient Air In CONDENSER OUTLET Warm Ambient Air Out WARM AIR RETURN FROM ENCLOSURE COOL AIR OUTLET TO ENCLOSURE 1 ...

Page 13: ...rammable Thermostat N A 0750 136 Standard Features 480 Volt 1 Phase Baked Powder Finish NEMA 4 models Built in Condensate Evaporator CFC Free Refrigerant Closed Loop Cooling Compressor Short Cycle Protector Compressor Short Cycle Protector Condenser Blower Controller Epoxy Coated Condenser and Evaporator Coils Filter Heavy duty Steel Shell NEMA 4 models Internal Corrosion Protection NEMA 4X models...

Page 14: ...operation under these conditions will cause damage shorten compressor life and void the warranty A Filter and condenser coil service The filter holder must be removed in order to clean the filters After removal the filters should be flushed under warm running water with clean side up If the accumulated dirt is oily washing in a detergent bath is recommended followed by a warm water wash as above T...

Page 15: ...Line Voltage Check Nameplate Voltage against supply Voltage Compressor and Condenser Blower do not run Return temperature is Failed Compressor Check Compressor wire connections above set point plus differential 90 F Check Compressor overload Check Compressor Capacitor Replace Compressor D Refrigerant Loss Kooltronic Air Conditioners are subjected to a series of tests to detect refrigerant leaks du...

Page 16: ...Clean Coil difference between return and Coil clogged supply air is less than 10 F Evaporator Blower Condenser Loss of Refrigerant Locate and repair leak Blower and Compressor are running Ice on Evaporator Coil Clean Evaporator Coil Check discharge and suction pressure for Refrigerant leak Check for any obstruction of Evaporator airflow Check and seal all openings Excessive condensate Eliminate th...

Page 17: ...received by customer Number of parts to be returned Product description model and serial number Reason for return Action requested Contact name telephone FAX numbers and e mail address Pack unit in a suitable container for shipment preferably the original packaging if available All Air Conditioners must be returned in an upright position properly secured to a pallet Improper packaging may void war...

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