nvent SPECTRACOOL G28 User manual

© 2019 nVent 89092263
Rev. I P/N 89092263
SPECTRACOOL™
Air Conditioner
G28 dC Model
INSTRUCTION MANUAL

© 2019 nVent 89092263
- 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
Sequence of Operation................................................................................................................................................................................... 6
Heating .................................................................................................................................................................................................... 6
Cooling..................................................................................................................................................................................................... 6
Standard and Optional Component Operation............................................................................................................................................. 6
Thermostat.............................................................................................................................................................................................. 6
Head Pressure Control........................................................................................................................................................................... 6
Door Switch............................................................................................................................................................................................. 6
Alarm Output........................................................................................................................................................................................... 7
Refrigerant Properties Chart (R134a) ........................................................................................................................................................... 7
Performance Data .......................................................................................................................................................................................... 8
6000/5000 BTU/Hr. Unit Characteristics...................................................................................................................................................... 8
Functional Data............................................................................................................................................................................................... 8
Wire Diagrams................................................................................................................................................................................................. 9
G280648GXXX Generic Wire Diagram (actual unit options may vary) .............................................................................................. 9
G280624GXXX Generic Wire Diagram (actual unit options may vary) ............................................................................................ 10
MAINTENANCE.............................................................................................................................................................................. 11
Compressor................................................................................................................................................................................................... 11
Inlet Air Filter ................................................................................................................................................................................................. 11
How To Remove, Clean or Install a New Inlet Air Filter ............................................................................................................................. 11
Condenser and Evaporator Air Movers....................................................................................................................................................... 11
Refrigerant Loss............................................................................................................................................................................................ 12
Service Data .................................................................................................................................................................................................. 12
G28 Series Components List....................................................................................................................................................................... 12
TROUBLE SHOOTING ....................................................................................................................................................................14
Basic Air Conditioning Trouble Shooting Check List................................................................................................................................. 14
Symptoms and Possible Causes: ............................................................................................................................................................... 15
F-GAS INFORMATION....................................................................................................................................................................15

© 2019 nVent
89092263 - 3 -
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 Sequence of Operation 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, 24 = 24 Volts DC
4. Unique set of numbers for each air conditioner which identies the accessories on a model.

© 2019 nVent 89092263
- 4 -
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.
5. Allow unit to remain upright for a minimum of ve minutes before starting. Caution! Air conditioner
must be in upright position during operation.
6. 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.
7. Set thermostat for required cabinet temperature. Refer to Sequence of Operation on page 6
for thermostat adjustment & operation.
DIMENSIONAL DRAWING
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89091095

© 2019 nVent
89092263 - 5 -
28-1000-13
SURFACE MOUNT
Figure 1
Cutout Dimensions

© 2019 nVent 89092263
- 6 -
TECHNICAL INFORMATION
SEQUENCE OF OPERATION
The air conditioner comes with two internally integrated thermostats. There are two modes of operation; heating
and cooling (heating is not available on all models). The evaporator fan will operate continuously at all times.
HEATING
When the enclosure temperature is below the heating thermostat setpoint, power is applied to the
heaters. When the enclosure temperature reaches 4 C (7 F) above the setpoint, the heater is powered off.
COOLING
When the enclosure temperature is above the cooling thermostat setpoint, power is applied to the
compressor. When the enclosure temperature drops to 6 C (11 F) below the setpoint, the compressor and
condenser impeller will power off.
The condenser impeller will be started and speed controlled based on condenser coil temperature. The
control will start the condenser impeller when the condenser coil temperature reaches 29 C (84 F) and
above. The impeller will increase in speed as the condenser coil temperature rises.
Operating the air conditioner below the minimum ambient temperature or above the maximum ambient
temperatures indicated on the nameplate voids all warranties. DO NOT set the enclosure thermostat
to a temperature lower than 21 C (70 F). Doing so can increase the likelihood of frost buildup on the
evaporator coil.
The moisture that the enclosure air can contain is limited. If moisture ows from the drain tube
continuously, this can only mean that ambient air is entering the enclosure. Be aware that frequent
opening of the enclosure door admits humid air that the air conditioner must then dehumidify.
STANDARD AND OPTIONAL COMPONENT OPERATION
THERMOSTAT
The G28 DC air conditioner uses a digital thermostat. The thermostat setpoint equals the temperature
that the air conditioner turns on. The thermostat has a 6 C (11 F) differential from setpoint until it calls for
cooling or heating. An example of operation is shown below.
For Cooling For Heating
Thermostat setpoint = 90 F Thermostat setpoint = 55 F
Cooling turns on at 90 F Heating turns on at 55 F
Cooling turns off at 80 F Heating turns off at 65 F
HEAD PRESSURE CONTROL
Unit is set at the factory, no adjustment is necessary.
At a condenser temperature below 29 C (84 F) 95 psig, the condenser fans will power off. At a condenser
temperature of 108 C (226 F), the condenser fan will be at full power.
DOOR SWITCH
This unit can be ordered with an optional door switch input. Models equipped with the door switch input
will require a customer supplied switch. The switch must be normally closed and must be rated for 48
VDC and 300mA minimum.

© 2019 nVent
89092263 - 7 -
ALARM OUTPUT
This unit can be ordered with an optional alarm output. The internal control board has a normally open
and normally closed relay output for alarming. The alarm relay has the following ratings:
Load Resistive load (cos =1)
Rated Load 0.3 A at 125 VAC
1 amp at 30 VDC
Contact Material Ag (Au clad)
Maximum Carry Current 1 A
Maximum Operating Voltage 125 VAC, 60 VDC
Maximum Operating Current 1 A
Maximum Switching Capacity 37.5 VA, 30 W
Minimum Permissible Load 10 μA at 10 mVDC
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

© 2019 nVent 89092263
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PERFORMANCE DATA
6000/5000 BTU/HR. UNIT CHARACTERISTICS
Model G280648GXXX G280624GXXX
Dimensional Data
Height (in. / mm) 28.60 / 726
Width (in. / mm) 16.97 / 382
Depth (in. / mm) 11.10 / 282
Unit Weight (lb. / kg) 84 / 38
Unit Protection Rating Type 12/4/4X/3R
Cooling Data
Refrigerant R134A
Refrigerant Charge (oz / grams) 17 / 482
Cooling Capacity at 95 F enclosure 95 F ambient (BTU/
Hr. / W) 6080 / 1781 5290/1550
Cooling Capacity at Max Conditions (BTU/Hr. / W) 6333 / 1855 6120/1793
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
Heating Data
Capacity TBD
Electrical Data
Rated Voltage (VDC) 48 24
Rated Frequency DC
Voltage Range 39-57 18-30
Cooling Amps at Max Conditions 26 54
Heating Amps TBD
Compressor RLA 23 48
Evaporator Fan RLA 1.5 2.4
Condenser Fan RLA 1.5 3.8
FUNCTIONAL DATA
Model Evaporator Air
In (°F) Amps (A) Condenser Delta (°F) Evaporator Delta (°F)
G280648GXXX 65-80 13-18 27-33 14-32
81-100 15-23 34-50 26-37
G280624GXXX 65-80 24-36 27-33 14-32
81-100 30-43 34-50 26-37

© 2019 nVent
89092263 - 9 -
WIRE DIAGRAMS
G280648GXXX GENERIC WIRE DIAGRAM (ACTUAL UNIT OPTIONS MAY VARY)
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© 2019 nVent 89092263
- 10 -
G280624GXXX GENERIC WIRE DIAGRAM (ACTUAL UNIT OPTIONS MAY VARY)
COMPRESSOR CONTROLLER
J3 J4 J5
J2 J1
JP6
JP5
A
B
C
OVER-
LOAD
COMPRESSOR
HEATER (OPT.)
YEL5
ORG4
BLU3
YEL5
BLU3
ORG4
EVAPORATOR
IMPELLER
CONDENSER
IMPELLER
WHT
WHT
RED
BLK
BLU
YEL
YEL15
BLU14
TEMP SENSOR
(COND COIL)
YEL
COMPRESSOR
HEATER
(OPT)
HEATER
LIMIT
SWITCH
(OPT)
TO CUSTOMER
PROVIDED DOOR
SWITCH (OPT)
YEL
YEL
BLU
BLK
RED
BLK
BLK
+ -
BLK
BLK
GROUND
0 VDC
24 VDC
TERMINAL
BLOCK
WHT6
WHT7
WHT7
WHT6
BLK13
BLK19
RED18
RED12
RED2
BLK1
RED30
BLK31
SPEED CONTROL
RESISTOR
137K OHM - 6K BTU
240K OHM - 5K BTU
YEL21
BLU20
BLK11
RED10
A/C
CONTROLLER
CMP HTR
-
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-
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+
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PWR
J16
J17
J8
J14
J13
J9 J11
J10
BLK
BLK
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BLK8
1
1
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1
1
1
1
1
11
1
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1
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BLK40
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89100025

© 2019 nVent
89092263 - 11 -
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 access cover. To access lter, loosen screw on access cover. Swing
top edge of access cover forward. Slide air lter up and out of retaining tabs. The lter may now be cleaned or
new lter installed.
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.

© 2019 nVent 89092263
- 12 -
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 G280624GXXX
Coil, Condenser 89051206
Coil, Evaporator 28-6010-00
Compressor 89090985 89099534
Compressor Controller 89085708 89099535
Control Board 89085851 89085851
Filter, Air, Reusable 10-1000-107
Filter/Dryer 52-6028-00
Heater, Compressor or Condenser Pan (optional) 10-1030-08
Thermistor, Evaporator / Condenser Coils 10-1106-118
Impeller, Condenser 10-1091-148 10-1091-149
Impeller, Evaporator 10-1091-144 10-1091-145

© 2019 nVent
89092263 - 13 -
NOTES

© 2019 nVent 89092263
- 14 -
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

© 2019 nVent
89092263 - 15 -
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
G280624GXXX
Refrigerant
Kühlmittel
Chłodziwo R134a
GWP 1430
Factory Charge
Füllmenge durch Hersteller
Opłata Fabryczna
482 Grams
482 Gramm
482 Gramów
CO2Equivalent
CO2Equivalent
CO2Ekwilalent
0.69 Tons
0,69 Tonnen
0,69 Tony

© 2019 nVent 89092263
- 16 -
NOTES

© 2019 nVent
89092263 - 17 -
NOTES

© 2019 nVent 89092263
- 18 -
NOTES

© 2019 nVent
89092263 - 19 -
NOTES

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