nvent SpectraCool G280648G Series User manual

© 2020 nVent 89174770
Rev. C P/N 89174570
SpectraCool
Air Conditioner
G28 48 VdC 2-StAGe Model
INSTRUCTION MANUAL

© 2020 nVent 89174770
- 2 -
NOTE: Some of the information in this manual may not apply if a special unit was ordered. If
additional drawings for a special unit are necessary, they have been inserted. Contact nVent
Equipment Protection if further information is required.
WARRANTY AND RETURN POLICY
https://hoffman.nvent.com/en/hoffman/warranty-information
TABLE OF CONTENTS
Warranty and Return Policy............................................................................................................................................................. 2
HANDLING & TESTING THE AIR CONDITIONER........................................................................................................................... 3
HOW TO READ MODEL NUMBERS................................................................................................................................................. 3
INSTALLATION INSTRUCTIONS..................................................................................................................................................... 4
Dimensional Drawing ..................................................................................................................................................................................... 4
TECHNICAL INFORMATION............................................................................................................................................................ 6
Refrigerant Properties Chart (R134a) ........................................................................................................................................................... 6
Performance Data .......................................................................................................................................................................................... 7
6000 BTU/Hr. Unit Characteristics................................................................................................................................................................ 7
Wire Diagrams................................................................................................................................................................................................. 8
G280648GXXX Generic Wire Diagram (actual unit options may vary) .............................................................................................. 8
MAINTENANCE................................................................................................................................................................................ 9
Compressor..................................................................................................................................................................................................... 9
Inlet Air Filter ................................................................................................................................................................................................... 9
How To Remove, Clean or Install a New Inlet Air Filter ............................................................................................................................... 9
Condenser and Evaporator Air Movers......................................................................................................................................................... 9
Refrigerant Loss............................................................................................................................................................................................ 10
Service Data .................................................................................................................................................................................................. 10
G28 Series Components List....................................................................................................................................................................... 10
REMOTE ACCESS CONTROL ........................................................................................................................................................11
Iintroduction.................................................................................................................................................................................................. 11
Energizing The Controller............................................................................................................................................................................. 11
Control Status Indication ............................................................................................................................................................................. 11
Displaying and Changing Program Variables............................................................................................................................................. 12
OPERATING PARAMETERS ......................................................................................................................................................................... 12
ALARM PARAMETERS ................................................................................................................................................................................. 12
Displaying Temperature Sensor #2............................................................................................................................................................. 12
Compressor Restart Time Delay ................................................................................................................................................................. 12
Alarm Output Contact .................................................................................................................................................................................. 12
Alarm Input Connection ............................................................................................................................................................................... 13
Alarm Condition Display............................................................................................................................................................................... 13
Air Conditioner Unit Communication Features.......................................................................................................................................... 13
USB Communication ............................................................................................................................................................................ 13
Ethernet Communication..................................................................................................................................................................... 13
Using The PC Interface Tool ........................................................................................................................................................................ 14
USB Communication Mode ................................................................................................................................................................. 14
Ethernet Communication Mode .......................................................................................................................................................... 14
Remote Access Control Pin-out .................................................................................................................................................................. 15
TROUBLE SHOOTING ....................................................................................................................................................................16
Basic Air Conditioning Trouble Shooting Check List................................................................................................................................. 16
Symptoms and Possible Causes: ............................................................................................................................................................... 17
F-GAS INFORMATION....................................................................................................................................................................17

© 2020 nVent
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RECEIVING THE AIR CONDITIONER
Inspect the air conditioner and check for concealed damage that may have occurred during shipment. Damage
evident upon receipt should be noted on the freight bill. Save the packing material and request an inspection.
Then le a claim with the delivering carrier within 15 days of delivery.
nVent Equipment Protection cannot accept responsibility for freight damages; however, we will assist you in any
way possible.
HANDLING & TESTING THE AIR CONDITIONER
If the air conditioner has been in a horizontal position, be certain it is placed in an upright, vertical or mounting
position for a minimum of ve (5) minutes before operating.
Do not attempt to operate the air conditioner while it is horizontal
or on its side, back or front. The refrigeration compressor is lled
with lubricating oil. This will cause permanent damage to the air
conditioner and also voids the warranty.
CAUTION
TEST FOR FUNCTIONALITY BEFORE MOUNTING THE AIR CONDITIONER TO THE ENCLOSURE.
Refer to nameplate for proper electrical current requirements, and then connect power cord to a properly
grounded power supply. Minimum circuit ampacity should be at least 125% of the amperage shown in the
design data section for the appropriate model. No other equipment should be connected to this circuit to prevent
overloading.
Immediately after applying power the evaporator blower (enclosure air) should start running. Operate the air
conditioner with the compressor running for ve to ten minutes. You will need to set the cooling thermostat below
the ambient temperature to operate the compressor.
Condenser air temperatures should be warmer than normal room temperatures within a few minutes after the
condenser impellers start.
See on page 6 for specics on how the unit operates when powered up.
HOW TO READ MODEL NUMBERS
G28 06 48 G150
1234
1. Identies the type/family of air conditioner and the approximate height (i.e. G28 = Global family
about 28” high).
2. This is the air conditioner’s listed capacity in BTU/Hr. at rated conditions. (i.e. 06 = 6000 BTU/Hr.
at 131/131 F)
3. 48 = 48 Volts DC
4. Unique set of numbers for each air conditioner which identies the accessories on a model.

© 2020 nVent 89174770
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INSTALLATION INSTRUCTIONS
1. Inspect the air conditioner. Verify proper functionality before mounting the air conditioner, see
HANDLING & TESTING THE AIR CONDITIONER on page 3.
2. Using the mounting gasket kit provided with the unit, install gaskets to the air conditioner.
3. Mount air conditioner on enclosure taking care not to damage the mounting gasket. The
mounting gasket is the seal between the air conditioner and the enclosure. Avoid dragging the air
conditioner on the enclosure with the mounting gasket attached as this could cause rips or tears
in the gasket and risk losing the water tight seal.
4. To avoid cross-threading mounting inserts, start bolts by hand before tightening with a wrench or
ratchet driver. Allow unit to remain upright for a minimum of ve minutes before starting. Caution!
Air conditioner must be in upright position during operation.
5. Refer to the nameplate for electrical requirements. Wire the unit to a properly grounded power
supply. Electrical circuit should be fused with slow blow or HACR circuit breaker.
6. Set thermostat for required cabinet temperature. Refer to on page 6 for thermostat
adjustment & operation.
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© 2020 nVent
89174770 - 5 -
28-1000-13
SURFACE MOUNT
Figure 1
Cutout Dimensions

© 2020 nVent 89174770
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TECHNICAL INFORMATION
REFRIGERANT PROPERTIES CHART (R134A)
°F °C Pressure °F °C Pressure
-40 -40 -14.7 60 15.6 58
-35 -37.2 -12.3 65 18.3 64
-30 -34.4 -9.7 70 21.1 71.5
-25 -31.7 -6.8 75 23.9 78
-20 -28.9 -4 80 26.7 86.7
-15 -26.1 085 29.4 95
-10 -23.3 290 32.2 105
-5 -20.6 495 35 113.3
0-17.8 7.5 100 37.8 125
5-15 9105 40.6 135
10 -12.2 12 110 43.3 146.7
15 -9.4 15 115 46.1 157.5
20 -6.7 18.5 120 48.9 170
25 -3.9 22 125 51.7 185
30 -1.1 26 130 54.4 197.5
35 1.7 30 135 57.2 213.3
40 4.4 35 140 60 230
45 7.2 40 145 62.8 246.7
50 10 45.5 150 65.6 263.8
55 12.8 51.5
N

© 2020 nVent
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PERFORMANCE DATA
6000 BTU/HR. UNIT CHARACTERISTICS
Model G280648GXXX
Dimensional Data
Height (in./mm) 28.60/726
Width (in./mm) 17.01/432
Depth (in./mm) 11.18/284
Unit Weight (lb./kg) 84/38
Unit Protection Rating Type 12/4/4X/3R
Cooling Data
Refrigerant R134A
Refrigerant Charge (oz/grams) 24/680
Stage 1 Cooling Capacity at 95 F enclosure 95 F ambient (BTU/Hr./W) 4650/1360
Stage 1 Cooling Capacity at Max Conditions (BTU/Hr./W) 5800/1700
Stage 2 Cooling Capacity at 95 F enclosure 95 F ambient (BTU/Hr./W) 5250/1540
Stage 2 Cooling Capacity at Max Conditions (BTU/Hr./W) 6500/1900
Maximum Ambient Temp (°F/°C) 131/55
Minimum Ambient Temp (°F/°C) -40/-40
Enclosure Airow (CFM) 220
External Airow (CFM) Variable, 300 max
Condensate Management Hose discharge/Optional
powered C/E
Electrical Data
Rated Voltage (VDC) 48
Rated Frequency DC
Voltage Range 39-57
Cooling Amps at Max Conditions 17.7
Evaporator Fan RLA 0.8
Condenser Fan RLA 2.2

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WIRE DIAGRAMS
G280648GXXX GENERIC WIRE DIAGRAM (ACTUAL UNIT OPTIONS MAY VARY)
*+#)&&#(D7H 6

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MAINTENANCE
COMPRESSOR
The compressor requires no maintenance. It is hermetically sealed, properly lubricated at the factory and should
provide years of satisfactory operating service.
Under no circumstances should the access tting covers be loosened, removed or tampered with.
Breaking of seals on compressor access ttings during warranty period will void warranty on hermetic system.
Recharging ports are provided for the ease and convenience of reputable refrigeration repair service personnel for
recharging the air conditioner.
INLET AIR FILTER
This air conditioner was designed with a dust resistant condenser coil. This allows it to be run lterless in most
applications. The air conditioner is shipped with a lter in place for your convenience. For lterless operation,
simply remove the lter. Should you decide the lter is necessary in your application, regular maintenance to
clean this lter will assure normal operation of the air conditioner. The easily removable inlet air lter is located
behind the front cover. If necessary lter maintenance is delayed or ignored, the maximum ambient temperatures
under which the unit is designed to operate will be decreased.
If the compressor’s operating temperature increases above designed conditions due to a dirty or clogged
lter (or plugged condenser coil), the air conditioner’s compressor will stop operating due to actuation of the
thermal overload cut-out switch located on the compressor housing. As soon as the compressor temperature
has dropped to within the switch’s cut-in setting, the compressor will restart automatically. However the above
condition will continue to take place until the lter or coil has been cleaned. It is recommended that power to
the air conditioner be interrupted intentionally when abnormally high compressor operating temperature causes
automatic shut-down of the unit. The above described shut-down is symptomatic of a clogged or dirty lter, thus
causing a reduction in cooling air ow across the surface of the compressor and condenser coil.
HOW TO REMOVE, CLEAN OR INSTALL A NEW INLET AIR FILTER
RP aluminum washable air lters are designed to provide excellent ltering eciency with a high dust holding
capacity and a minimum amount of resistance to air ow. Because they are constructed entirely of aluminum,
they are lightweight and easy to service. To achieve maximum performance from your air handling equipment, air
lters should be cleaned on a regular basis.
The inlet air lter is located behind the front cover. The lter may be accessed for cleaning or replacement
through the slots in the side panels.
Cleaning Instructions:
1. Clean the lter with warm water from the exhaust side to the intake side. DO NOT USE CAUSTICS.
2. After ushing, allow the lter to drain. Placing a lter corner down will assure complete drainage.
CONDENSER AND EVAPORATOR AIR MOVERS
Impeller motors require no maintenance. All bearings, shafts, etc. are lubricated during manufacturing for the life
of the motor.
If the condenser impeller motor (ambient impeller) should fail, it is not necessary to remove the air conditioner
from the cabinet or enclosure to replace the blower. The condenser blower is mounted on its own bulkhead and is
easily accessible by removing the front cover.
Caution! Operation of the air conditioner in areas containing airborne caustics or chemicals can rapidly
deteriorate lters, condenser coils, blowers and motors, etc. Contact nVent for special recommendations.

© 2020 nVent 89174770
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REFRIGERANT LOSS
Each air conditioner is thoroughly tested prior to leaving the factory to insure against refrigeration leaks. Shipping
damage or microscopic leaks not found with sensitive electronic refrigerant leak detection equipment during
manufacture may require repair or recharging of the system. This work should only be performed by qualied
professionals, generally available through a local, reputable air conditioning repair or service company.
Should the refrigerant charge be lost, access ports on the suction and discharge sides of the compressor are
provided for recharging and/or checking suction and discharge pressures.
Refer to the data on the nameplate which species the type of refrigerant and the charge size in ounces.
Before recharging, make sure there are no leaks and that the system has been properly evacuated into a
deepvacuum.
SERVICE DATA
G28 SERIES COMPONENTS LIST
Part Description G280648GXXX
Coil, Condenser 89051206
Coil, Evaporator 28-6010-00
Compressor 89174109
Compressor Controller 89174133
Controller 89174555
Filter, Air, Reusable 89119662
Filter/Dryer 52-6028-00
Heater, Compressor or Condenser Pan (optional) 10-1030-08
Thermistor 89075654
Impeller, Condenser 89102441
Impeller, Evaporator 89102440
Fuse, Controller 89085114
Condenser Impeller Controller 89122338
Relay, Compressor 10-1005-22

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REMOTE ACCESS CONTROL
IINTRODUCTION
The Remote Access Control is a parametric controller for the complete management of air conditioners. All
settings are pre-programmed at the factory. Cooling/heating set-points, cooling/heating differential and high /low
temperature alarm set-points can be adjusted by the user. Alarms are outputted through a relay contact and also
can be accessed through an Ethernet connection utilizing SNMP, EtherNet/IP and Modbus TCP. A USB connection
is also provided and can be used to interface with the controller utilizing Modbus RTU.
ENERGIZING THE CONTROLLER
The controller is wired and programmed at the factory to be energized when power is supplied to the air
conditioner.
CONTROL STATUS INDICATION
The display has numerous symbols that indicate if the controller is heating, cooling, alarming, if the compressor
is enabled, and if the ambient fan is enabled. The 3 alpha-numeric characters further describe alarms and show
the cabinet temperature by default.
SYMBOL COLOR ICON ON ICON FLASHING
1AMBER Compressor On Stage 1 Start-up Request
2AMBER Compressor On Stage 2 Start-up Request Stage 2
3,4 AMBER Not Used Not Used
AAMBER Compressor On Not Used
BAMBER Evaporator Fan On Start-up Request
CAMBER Not Used Not Used
DAMBER Not Used Not Used
EAMBER Heater Active Not Used
FRED Alarm Active Not Used
GAMBER Controller Active Not Used
HAMBER Not Used Not Used

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DISPLAYING AND CHANGING PROGRAM VARIABLES
Access: To view and/or change parameters, press and hold the Prg and Sel buttons for greater than 5 seconds.
Press the up or down arrow buttons until “22” is displayed, then press Sel button. When “S-P” is displayed,
pressSel.
Navigation: Press up or down arrows to display sub-menus then press Sel to select the desired sub-menu. In the
sub-menu, use up or down arrows to display parameters for viewing or changing and press Sel. Use Prg button to
back out of menu levels as desired.
Adjust: Use the up or down arrows to change the parameter value then push Sel to save that setting. If Sel is not
pressed, the change to the value will not be saved. Navigate to and change other parameters as desired. When
nished, push Prg to back out of the sub-menus to the main menu.
NOTE: The display will revert to normal temperature display mode if no buttons are pressed
for 60 seconds.
OPERATING PARAMETERS
Parameter Default Value Range Description
r01 80 F 72 F to 120 F Cooling set-point
r02 7 F -Cooling differential
r07 3 F -Cooling differential Stage 2
A04 50 F* 32 F to 60 F Heating set-point*
A05 7 F* -Heating differential*
Cooling turns on at r01 + r02, and off at r01
Cooling Stage 2 turns on at r01 + r02 + r07, and off at r01 + r02
Heating turns on at A04, and off at A04 + A05
*Functional only on units with heater option
ALARM PARAMETERS
Parameter Default Value Description
P16 158 F High Temperature Alarm
P19 40 F Low Temperature Alarm
DISPLAYING TEMPERATURE SENSOR #2
Sensor number 2, the air outlet or condenser coil sensor, can be viewed at any time by pressing the up or down
arrow button on the front panel of the controller display. The display will revert to displaying temperature sensor
number 1 (the AC inlet temperature) after 60 seconds. Both sensors can also be read through the Ethernet and
USB connections.
COMPRESSOR RESTART TIME DELAY
A factory set 6 minute (360 second) restart delay exists to reduce residual back pressure before allowing the
compressor to restart. The compressor will stay off for the entire restart duration after the compressor is
disabled. A ashing “1” on the controller display will indicate the unit is in a compressor restart delay while calling
for cooling.
ALARM OUTPUT CONTACT
The Remote Access Control has a normally closed dry contact alarm output with a resistive load rating of
250VAC at 3 amps. Two yellow 18 AWG wires located at the back of the air conditioner provide a connection to
this output.

© 2020 nVent
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ALARM INPUT CONNECTION
The Remote Access Control can accept a dry contact/switch input via the two 18 AWG white wires located at the
back of the air conditioner. This input is associated with the controller display alarm mnemonic TP (door open
and/or smoke detected). [To use this feature, remove the splice connector connecting the two white wires and
connect customer supplied enclosure door switch in its place.]
ALARM CONDITION DISPLAY
There are seven possible non-latching alarm conditions detectable by the controller and are indicated on the
controller display. All alarms can also be accessed through the Ethernet and USB connections.
Alarm Mnemonic Description Cause Result Alarm Relay
TP General Alarm Door open and/or
smoke detected Unit turns off for duration of alarm Relay Contacts Close
LA High Pressure Warning MALF high pressure
switch opens No effect on function N/A
E1 Air Inlet Temperature
Sensor Alarm Sensor Failure Unit turns off for duration of alarm Relay Contacts Close
E2 Air Outlet Temperature
Sensor Alarm Sensor Failure Unit turns off for duration of alarm Relay Contacts Close
Ht High Temperature Alarm
Default = 125 F
Cabinet over
temperature
Alarm clears at default
setting -2 F
No effect on function Relay Contacts Close
Lt Low Temperature Alarm
Default = 40 F
Cabinet under
temperature
Alarm clears at default
setting +27 F
No effect on function N/A
A1 Frost Alarm Evaporator coil frozen
Alarm clears at 59 F
Compressor and
Evaporator fan off for
duration of alarm Relay Contacts Close
AIR CONDITIONER UNIT COMMUNICATION FEATURES
Air conditioner units equipped with communication capabilities provide SNMP, EtherNet/IP and Modbus TCP
protocols through Ethernet and Modbus RTU protocol via USB. Hoffman®Cooling has a PC Interface Tool
available for download that can utilize either mode to communicate with the air conditioner unit.
USB COMMUNICATION
This communication mode allows direct connection of a PC to the air conditioner unit. The protocol
supported is Modbus RTU. Use the PC Interface Tool to communicate with the air conditioner unit. A
MINI-b USB connection is provided.
ETHERNET COMMUNICATION
This communication mode allows remote connection to the air conditioner unit using SNMP, EtherNet/IP
and Modbus TCP protocols. Customers using their own software can download a MIB le for SNMP, EDS
le or EtherNet_IP Object le for EtherNet/IP and Coil_Register le for Modbus TCP.
Note: ACU has a default IP Address of 192.168.1.2
Both Ethernet and USB communication modes allow the ability to:
• Read ACU inlet and outlet air temperatures
• Read and change Cooling Set-point and Cooling Differential
• Read and change Heating Set-point, Heating Differential
• Read and change High and Low Temperature Alarm Settings
• Read and change Gateway IP Address, Device IP Address, Subnet Mask, Trap IP Address and Community
• Read and change Unit Identication
• Read and change the state of IP addressing (static or dynamic)
• Read current Alarm Status
SOFTWARE AND CONFIGURATION FILE DOWNLOADS
The PC Interface Tool, MIB le, EDS le, EtherNet_IP Object le and Coil_Register le can be downloaded
from www.nVent.com/HOFFMAN

© 2020 nVent 89174770
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USING THE PC INTERFACE TOOL
The PC Interface Tool gives the user the ability to communicate with the air conditioner unit to read/write
parameters using either Ethernet or USB connections.
USB COMMUNICATION MODE
NOTE: Before connecting unit to the PC, make note of the comm ports present. After the unit
is connected to the PC, a new comm port will be added to the list. Use this new comm port.
• From Tools menu select Use Ethernet
• When Use Ethernet is unchecked, then Comm Port menu is enabled, Device IP and Community boxes are not
shown, and USB communication can be used
• To set the comm port, choose Comm Port from the Tools menu and then select the comm port from the combo box
VIEWING AIR CONDITIONER UNIT VALUES
To view Air Conditioner Unit values
• Select the ACU Values tab
• Select the Enable Comm button (the PC Interface will now be communicating with unit)
• To stop communication select the Disable Comm button
CHANGING AIR CONDITIONER UNIT VALUES
To change ACU Values
• Select the Settings tab
• Select the value to change
• Make the change to the value
• Select the Change Setting button
• Change can be veried in ACU Values tab
VIEWING AND CHANGING ETHERNET INFORMATION
To view and change Ethernet Information
• Select Ethernet Info tab
To view Ethernet Information
• Click Read Ethernet Info button
To change to dynamically assigning IP Address Mode
• Check Use DHCP Server checkbox
• Enter Trap IP Address and Community
• Click Load Ethernet Info button
To change to statically assigning IP Address Mode
• Uncheck Use DHCP Server checkbox
• Enter Device IP Address, Subnet Mask, Gateway IP Address, Trap IP Address and Community
• Click Load Ethernet Info button
ETHERNET COMMUNICATION MODE
• From Tools menu select Use Ethernet
• When Use Ethernet is checked, Comm Port selection is disabled, Device IP and Community boxes are shown and
Ethernet communication can be used.
• Enter unit’s IP Address and Community string in Device IP and Community boxes at the bottom of the PC Interface Tool.
Each unit has two community strings. One is a Read/Write community string (defaulted to
‘private’) that can be changed by the customer (must be 4 to 8 characters long). The other is a
Read-Only community string (‘public’) and cannot be changed.
VIEWING AIR CONDITIONER UNIT VALUES
To view Air Conditioner Unit values
• Select the ACU Values tab
• Select the Enable Comm button (the PC Interface will now be communicating with unit)
• To stop communication select the Disable Comm button
CHANGING AIR CONDITIONER UNIT VALUES
To change ACU Values
• Select the Settings tab
• Select the value to change
• Make the change to the value
• Select the Change Setting button
• Change can be veried in ACU Values tab

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VIEWING AND CHANGING ETHERNET INFORMATION
To view and change Ethernet Information
• Select Ethernet Info tab
To view Ethernet Information
• Click Read Ethernet Info button
To change to dynamically assigning IP Address Mode
• Check Use DHCP Server checkbox
• Enter Trap IP Address and Community
• Click Load Ethernet Info button
To change to statically assigning IP Address Mode
• Uncheck Use DHCP Server checkbox
• Enter Device IP Address, Subnet Mask, Gateway IP Address, Trap IP Address and Community
• Click Load Ethernet Info button
ALARM LOG ACCESSIBLE WITH SNMP
• Using custom software with the provided MIB le gives the ability to view a log of the last 25 alarms
REMOTE ACCESS CONTROL PIN-OUT
FUNCTION NAME PIN # WIRE #
U1 OUTPUTS
COOL No1 1ORG78
C1/2 2BLK
HEAT No2 7BRN76
C1/2 3BLK
ENCL MI No3 8BLK77
C3/4 4BLK
NA No4 (na) 9BLK
C3/4 10 BLK
ALARM RELAY OUTPUT No5 12 YEL39
C5 6YEL38
NA x5NA
NA x11 NA
U2 INPUTS
ALARM INPUT
CONNECTION ID1 8WHT63
MALFUNCTION NC SWITCH ID2 1BLU88
NA ID3 (na) 9BLU
NA ID4 (na) 2BLU
NA ID5 (na) 10 BLU
DIGITAL INPUT GROUND ID GND 3BLU
NA Y (na) 4NA
NA GND (na) 5NA
T1, EVAP IN THERMISTOR B1 13 RED
T2, EVAP OUT THERMISTOR B2 12 RED
T1, T2 GND GND 6WHT
NA B3 11 NA
CONTROLLER POWER G 7 BLK40
CONTROLLER POWER G0 14 WHT41
U3 DATA
POWER 1RED
GROUND 2BLACK
DIRECTION 3GREEN
DATA 4WHITE

© 2020 nVent 89174770
- 16 -
TROUBLE SHOOTING
BASIC AIR CONDITIONING TROUBLE SHOOTING CHECK LIST
1. Check manufacturer’s nameplate located on the unit for correct power supply.
2. Turn on power to the unit. The evaporator (Enclosure or “COLD” air) impeller should come on. Is
there airow?
YES, proceed to step 3.
NO, possible problem:
• Open motor winding
• Stuck impeller motor
• Obstructed wheel
Repair or Replace
defective part
3. Check thermostat setting and adjust the thermostat to the lowest setting. This should turn on the
compressor. When the condenser coil temperature reaches 29 C (84 F) The condenser impeller
will turn on. Did the compressor come on when the thermostat was turned on? Did the condenser
impeller come on when the condenser reached 29 C (84 F)?
YES, proceed to step 4.
NO, possible problem:
• Tripped customer door switch
• Defective thermostat Replace Part
4. Are all impellers and the compressor running? If not the unit will not cool properly.
5. Check condenser (Ambient or “HOT” air) impellers for airow. Is there airow?
YES, proceed to step 6.
NO, possible problem:
• Defective thermostat
• Open motor winding
• Stuck impeller motor
• Obstructed wheel
• Defective condenser thermistor
Repair or Replace
defective part
6. Carefully check the compressor for operation - motor should cause slight vibration, and the outer
case of the compressor should be warm. Is the compressor showing signs of this?
YES, wait 5 minutes, then proceed to step 7.
NO, possible problem:
• Defective thermostat
• Defective compressor controller
• Defective overload
Repair or Replace
defective part
7. Make sure the coils are clean. Then check evaporator “air in” and “air out” temperatures. If the
temperatures are the same:
• Possible loss of refrigerant
• Possible bad valves in the
compressor
Repair or Replace
defective part

© 2020 nVent
89174770 - 17 -
SYMPTOMS AND POSSIBLE CAUSES:
SYMPTOM POSSIBLE CAUSE
Unit won’t cool
Clogged ns on coil(s)
Dirty lter
Impellers not running
Compressor not running
Compressor runs, but has bad valves
Loss of refrigerant
Compressor tries to start but won’t run
Low line voltage at start. Should be +/-10% rated voltage.
Compressor motor stuck
Bad control
Bad overload switch
Unit blows breakers Undersized breaker/fuse or not time delayed
Short in system
Getting water in enclosure
Drain plugged
Drain tube kinked
Enclosure not sealed (allowing humidity in)
Mounting gasket damaged
For additional technical support, contact nVent Equipment Protection at 800-896-2665.
F-GAS INFORMATION
G280648GXXX
Refrigerant
Kühlmittel
Chłodziwo R134a
GWP 1430
Factory Charge
Füllmenge durch Hersteller
Opłata Fabryczna
680 Grams
680 Gramm
680 Gramów
CO2Equivalent
CO2Equivalent
CO2Ekwilalent
0.97 Tons
0,97 Tonnen
0,97 Tony

© 2020 nVent 89174770
- 18 -
NOTES

© 2020 nVent
89174770 - 19 -
NOTES

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