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• Low voltage control connections are made to low voltage pigtails
extending  from  top  of  air  handler  (see  Figure  1).  Connections  for
control wiring are made with wire nuts. Control wiring knockouts (7/8˝)
are also provided on the right and left side of the unit for side connec-
tion.

• See wiring diagrams attached to indoor and outdoor sections to be
connected.

• Make sure, after installation, separation of control wiring and power
wiring has been maintained.

3.8.3 GROUNDING

The unit must be permanently grounded. Failure to do so can 
result in electrical shock causing personal injury or death.    

• Grounding may be accomplished when installed in accordance with 
electrical codes by bonding the metal conduit to the unit cabinet or by 
attaching ground wire(s) to ground lug(s) provided in the unit wiring
compartment.

• Ground lug(s) are located close to wire entrance on left side of unit
(upflow).  Lug(s)  may  be  moved  to  marked  locations  near  wire
entrance on right side of unit (upflow) if alternate location is more
convenient.

• Use of multiple supply circuits require grounding of each circuit to
lug(s) provided in unit.

• If required, install a branch circuit disconnect of adequate size,
located within sight of, and readily accessible to the unit.

IMPORTANT

:  After  the  Electric  Heater  is  installed,  units  are

equipped  with  one  30-60  amp.  circuit  breaker.  These  breaker(s)
protect the internal wiring in the event of a short circuit and serve as
a disconnect. Circuit breakers installed within the unit do not provide
over-current  protection  of  the  supply  wiring  and  therefore  may  be
sized larger than the branch circuit protection.

Supply  circuit  power  wiring  must  be  75°C  minimum  copper

conductors  only.  See  Electrical  Data  in  this  section  for  ampacity,
wire size and circuit protector requirements. Supply circuit protective 
devices may be either fuses or “HACR” type circuit breakers.
• Power wiring may be connected to either the right or left side

.

Two 7/8” dia. concentric knockouts are provided for connection of
power wiring to unit.
• Power  wiring  is  connected  to  the  power  terminal  block  in  unit
electric cabinet.

3.8.2 CONTROL WIRING

IMPORTANT: Class 2 low voltage control wiring should not be run in 
conduit with main power wiring and must be separated from power 
wiring, unless class 1 wire of proper voltage rating is used. 

Select  a  thermostat  that  is  commonly  used  with  HP  or  AC  single 
stage heating/cooling with electric heat. The thermostat will energize 
the fan on a demand for heating or cooling.

Install the thermostat on an inside wall, away from drafts, lights or 
other heat sources in a location that has sufficient air circulation from 
other  rooms  being  controlled  by  the  thermostat.  The  thermostat 
should be mounted 4 to 5 feet above the floor.

• Low  voltage  control  wiring  should  be  18 Awg.  color-coded.  For
lengths longer than 100 ft., 16 Awg. wire should be used.

Field wiring must comply with the National Electric Code (C.E.C. in 
Canada) and any applicable local ordinance.  

Disconnect all power to unit before installing or servicing.  More 
than one disconnect switch may be required to de-energize the 
equipment. Hazardous voltage can cause severe personal injury 
or death.      

3.8.1 POWER WIRING

It is important that proper electrical power is available for connection 
to  the  unit  model  being  installed.  See  the  unit  nameplate,  wiring 
diagram and electrical data in the installation instructions.

WARNING 

WARNING 

3.5 Refrigerant Piping

Refrigerant  pipe  connections  are  located  on  the  top  of  the  unit. 
Refrigerant piping external to the unit shall be sized in accordance 
with  the  instructions  of  the  outdoor  equipment.  When  units  are 
recessed mounted in the wall, make certain that piping connections 
are pressure tested prior to the wall being closed. While brazing, be 
sure to protect the cabinet and grommets from heat damage.

3.6 Metering Device

All  units  are  shipped  and  installed  with  throttle  designed  for  air 
conditioning  operation.  Pressures  equalize  after  shut  down.  Some 
outdoor models may require a start assist kit. See outdoor unit for 
more information.

3.7 Blower

3.8 Wiring

3.10 Thermostat

An air filter must be installed before air enters the evaporator coil in 
order  to  protect  the  coil,  blower,  and  other  internal  parts  from 
excessive dirt and dust  A filter must be installed. Consult the filter 
manufacturer for proper sizing and maximum velocity requirements.

3.9 Air Filter

This  unit  is  supplied  with  a  multi-speed  PSC  motor  with  a  direct 
drive  blower  wheel  which  can  obtain  various  air  flows. The  unit  is 
shipped  with  factory  set  cooling  and  heating  speed  taps.  Airflow 
performance  tables  are  available  for  additional  speed  taps. 
Disconnect all power to the unit before making any adjustments to 
the  motor  speed  taps.  Be  sure  to  check  the  air  flow  and  the 
temperature drop across the evaporator coil to ensure sufficient air 
flow.

Filter Sizes 

18/24 

16Χ20[406Χ508] 

MODEL 

FILTER SIZE IN [mm]  

30/36 

20Χ20[508Χ508] 

6

Summary of Contents for OXBOX JMM4A0A18S21SAA

Page 1: ...single phase 5 7 5 and 10 kW heaters All aluminum coil Factory installed piston style refrigerant control Field installed TXV kits available Blower and coil slide out easily for maintenance Factory sealed cabinet certified to achieve 2 or less air leakage rate at 1 0 inch water column Front or bottom return air Painted finish on galvanized steel Sturdy polycarbonate drain pans Air handler has fact...

Page 2: ... state electrical code on requirements for grounding Failure to follow this warning could result in property damage serious personal injury or death HAZARDOUS VAPORS Do not install an air handler with a non ducted return in the same closet alcove or utility room as a fossil fuel device Hazardous vapors can be distributed throughout the conditioned space and equipment damage can result Section 2 Sa...

Page 3: ...ins adhesives cleaning compounds and cement creates a corrosive condition which may cause rapid deterioration of the cabinet and internal components CAUTION SAFETY HAZARD Sharp Edge Hazard Be careful of sharp edges on equipment or any cuts made on sheet metal while installing or servicing Personal injury may result WARNING Make sure the blower motor support is tight 3 motor mount bolts then check ...

Page 4: ...mounting bracket and attach the unit to the installed bracket Reference Figure 3 1 4 Install the additional bottom plate for extra support for this type mounting see figure 3 1 Note The additional plate is shipped in the bottom of the shipping carton only for 30 36k unit 3 2 1 WALL MOUNT Fig 3 2 FRAME MOUNT The air handler comes with 8 clearance holes 4 on each side These holes are used to mount t...

Page 5: ...idential Winter and Summer Air Conditioning and Equipment Selection Latest editions are available from ACCA Air Conditioning Contractors of America 1513 16th Street N W Washington D C 20036 If duct system incorporates flexible air duct be sure pressure drop information straight length plus all turns shown in ACCA Manual D is accounted for in system Supply plenum is attached to the 3 4 duct flanges...

Page 6: ...HP or AC single stage heating cooling with electric heat The thermostat will energize the fan on a demand for heating or cooling Install the thermostat on an inside wall away from drafts lights or other heat sources in a location that has sufficient air circulation from other rooms being controlled by the thermostat The thermostat should be mounted 4 to 5 feet above the floor Low voltage control w...

Page 7: ...oints are tight 7 Be sure the return air filter is installed 8 Operate complete system in each mode to verify proper performance Verify operation of supplementary electric heater 7 3 13 Maintenance The system air filter s should be inspected cleaned or replaced at least monthly Make certain that the access panels are replaced and secured properly before placing the unit back in operation This prod...

Page 8: ...ctric heaters 8 N E C class2 24volts Factory default fan speed is medium FM red wire connected to FR 4 For HI speed connect FM black wire to FR 4 For LOW speed connect FM blue wire to FR 4 and FM red wire to FR 6 Always connect the unused FM wire to the dummy terminal CN3 connect the plug to electric heaters kit when applied FM T A T S O M R E H T O T PLUG PLATE SEE NOTE 4 SCHEMATIC DIAGRAM COMPON...

Page 9: ... 1290 1263 1196 1116 1051 980 907 Med 1298 1252 1198 1147 1094 1037 976 910 842 Low 1149 1105 1056 1008 960 909 856 791 726 36 EXTERNAL STATIC PRESSURE in w c 24 30 MODEL JMM4A BLOW ER SPEEDS 18 Shaded boxes represent airflow outside the required 300 450 cfm ton NOTES 1 Airflow based upon dry coil at 230V with no electric heat and factory approved filter 2 Airflow is equivalent for front or bottom...

Page 10: ...applications section for more detail Primary drain conncetion 3 4 female pipe thread NPT Auxiliary drain connection 3 4 female pipe thread NPT NOTE Hand tighten only Section 7 Dimensional Data DIMENSIONAL DATA 18 88 101 40 46 MODEL SIZE Dimensions inch mm UNIT HEIGHT H IN mm UNIT WIDTH W IN mm UNIT LENGTH D IN mm 88 101 40 46 24 UNIT WIDTH W1 IN mm UNIT WEIGHT SHIPPING WEIGHT LBS kg UNIT LENGTH D1...

Page 11: ...MENSIONS A B C JMM4A0A18S21SAA 24 9 10 150 10 1 8 61 119 1 20 717 JMM4A0A24S21SAA 24 9 10 150 10 1 8 61 119 1 20 717 JMM4A0B30S21SAA 24 9 10 150 10 1 8 61 132 795 JMM4A0B36S31SAA 24 9 10 150 10 1 8 61 132 795 Model number Dimension inch mm ...

Page 12: ...our local dealer distributor Since the manufacturer has a policy of continuous product and product data improvement it reserves the right to change the design and specification without notice 16123000A19244 V2 0 www oxboxhvac com 2019TwentyThreeC LLC 800 Beaty Street ...

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