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13ACX SERIES

STEP 4 -- ELECTRICAL -- Circuit Sizing and Wire Routing

In the U.S.A., wiring must conform with current local codes and
the current National Electric Code (NEC). In Canada, wiring
must conform with current local codes and the current
Canadian Electrical Code (CEC).
Refer to the furnace or air handler installation instructions for
additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.

24VAC TRANSFORMER

Use the transformer provided with the furnace or air handler
for low‐voltage control power (24VAC - 40 VA minimum)

WARNING

Electric Shock Hazard. Can cause injury or
death. Unit must be grounded in
accordance with national and local codes.
Line voltage is present at all components
when unit is not in operation on units with
single‐pole contactors. Disconnect all
remote electric power supplies before
opening access panel. Unit may have
multiple power supplies.

IMPORTANT !

If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start-up to prevent
compressor damage as a result of slugging.

CAUTION

ELECTROSTATIC

DISCHARGE

(ESD)

Precautions and

Procedures

Electrostatic discharge can affect
electronic components. Take care during
unit installation and service to protect the
unit's electronic controls. Precautions will
help to avoid control exposure to
electrostatic discharge by putting the unit,
the control and the technician at the same
electrostatic potential. Touch hand and all
tools on an unpainted unit surface before
performing any service procedure to
neutralize electrostatic charge.

Refer to the unit nameplate for minimum circuit ampacity,
and maximum fuse or circuit breaker (HACR per NEC).
Install power wiring and properly sized disconnect switch.

NOTE — Units are approved for use only with copper
conductors. Ground unit at disconnect switch or
connect to an earth ground.

SIZE CIRCUIT AND INSTALL SERVICE

DISCONNECT SWITCH

NOTE — 24VAC, Class II circuit connections are made
in the control panel.

Install room thermostat (ordered separately) on an inside
wall approximately in the center of the conditioned area
and 5 feet (1.5m) from the floor. It should not be installed
on an outside wall or where it can be affected by sunlight
or drafts.

THERMOSTAT

5 FEET

(1.5M)

INSTALL THERMOSTAT

SERVICE

DISCONNECT

SWITCH

MAIN FUSE BOX/

BREAKER PANEL

FIGURE 13

Summary of Contents for Merit 13ACX-018-230

Page 1: ... Units AIR CONDITIONER 506945 01 5 2013 Supersedes 7 2012 WARNING Improper installation adjustment alteration service or maintenance can cause personal injury loss of life or damage to property Installation and service must be performed by a licensed professional installer or equivalent or a service agency CAUTION Before attempting to perform any service or maintenance turn the electrical power to...

Page 2: ...ICE Roof Damage This system contains both refrigerant and oil Some rubber roofing material may absorb oil causing the rubber to degrade Failure to follow this notice could result in damage to roof surface IMPORTANT This model is designed for use in check expansion valve systems only An indoor expansion valve ap proved for use with HFC 410A refrigerant must be or dered separately and installed prio...

Page 3: ...THE LIQUID LINE TO THE VAPOR LINE FLOOR JOIST OR ROOF RAFTER REFRIGERANT LINE SET INSTALLING HORIZONTAL RUNS NOTE Similar installation practices should be used if line set is to be installed on exterior of outside wall PVC PIPE FIBERGLASS INSULATION CAULK OUTSIDE WALL VAPOR LINE WRAPPED WITH ARMAFLEX LIQUID LINE OUTSIDE WALL LIQUID LINE VAPOR LINE WOOD BLOCK BETWEEN STUDS STRAP WOOD BLOCK STRAP SL...

Page 4: ...t that the refrigerant system be kept closed as much as possible DO NOT remove line set caps or service valve stub caps until you are ready to make connections IMPORTANT Some scroll compressors have an internal vacuum protector that will unload scrolls when suction pres sure goes below 20 psig A hissing sound will be heard when the compressor is running unloaded Protector will reset when low press...

Page 5: ... Teflon rings H Use a field provided fitting to temporarily reconnect the liquid line to the indoor unit s liquid line orifice housing LOW HIGH EXISTING INDOOR UNIT GAUGE MANIFOLD CYLINDER CONTAINING CLEAN HCFC 22 TO BE USED FOR FLUSHING Positioned to deliver liquid refrigerant LIQUID LINE SERVICE VALVE INLET DISCHARGE TANK RETURN CLOSED OPENED RECOVERY CYLINDER RECOVERY MACHINE NEW OUTDOOR UNIT V...

Page 6: ...nts and debur the ends The pipe must remain round Do not crimp end of the line Remove service cap and core from both the suction vapor and liquid line service ports 1 2 ANGLE TYPE SERVICE VALVE SERVICE PORT CORE SERVICE PORT CAP SERVICE PORT CORE SERVICE PORT CAP CUT AND DEBUR LINE SET SIZE MATCHES SERVICE VALVE CONNECTION COPPER TUBE STUB SERVICE VALVE CONNECTION REFRIGERANT LINE DO NOT CRIMP SER...

Page 7: ...ed cloths WHEN BRAZING LINE SET TO SERVICE VALVES POINT FLAME AWAY FROM SERVICE VALVE PREPARATION FOR NEXT STEP 7 WRAP SERVICE VALVES To help protect service valve seals during brazing wrap water saturated cloths around service valve bodies and copper tube stubs Use additionalwater saturated cloths underneath the valve body to protect the base paint 4 FLOW NITROGEN Flow regulated nitrogen at 1 to ...

Page 8: ...6 7 8 9 10 11 12 1 2 Turn SENSING BULB INSTALLATION EQUALIZER LINE INSTALLATION 1 2 3 4 5 6 7 8 9 10 11 12 1 8 Turn A Remove and discard either the flare seal cap or flare nut with copper flare seal bonnet from the equalizer line port on the vapor line as illustrated in the figure below B Remove the field provided fitting that temporarily reconnected the liquid line to the indoor unit s distributo...

Page 9: ... indoor unit E After a few minutes open one of the service valve ports and verify that the refrigerant added to the system earlier is measurable with a leak detector F After leak testing disconnect gauges from service ports After the line set has been connected to the indoor and outdoor units check the line set connections and indoor unit for leaks Use the following procedure to test for leaks A C...

Page 10: ...utting off the vacuum pump and closing the manifold gauge valves F When the absolute pressure requirement above has been met disconnect the manifold hose from the vacuum pump and connect it to a cylinder of HFC 410A positioned to deliver liquid refrigerant Open the manifold gauge valve 1 to 2 psig in order to release the vacuum in the line set and indoor unit G Perform the following A Connect low ...

Page 11: ... damage as a result of slugging CAUTION ELECTROSTATIC DISCHARGE ESD Precautions and Procedures Electrostatic discharge can affect electronic components Take care during unit installation and service to protect the unit s electroniccontrols Precautionswill help to avoid control exposure to electrostatic dischargebyputtingthe unit the control and the technician at the same electrostatic potential To...

Page 12: ...binding 2 Inspect all factory and field installed wiring for loose connections 3 After evacuation is complete open the liquid line and suction line service valve stems to release the refrigerant charge contained in outdoor unit into the system 4 Replace the stem caps and tighten to the value listed in table 3 5 Check voltage supply at the disconnect switch The voltage must be within the range list...

Page 13: ...nsion 3 16 for liquid line valve sizes and 5 16 for vapor line valve sizes to back the stem out counterclockwise as far as it will go Operating Ball Type Service Valve 1 Remove stem cap with an appropriately sized wrench 2 Use an appropriately sized wrenched to open To open valve rotate stem counterclockwise 90 To close rotate stem clockwise 90 1 2 3 4 5 6 7 8 9 10 11 12 1 12 TURN To Access Servic...

Page 14: ...nged exposure of the unit to treated water i e sprinkler systems soak ers waste water etc will corrode the surface of steel and aluminum parts diminish performance and af fect longevity of the unit Routine Maintenance In order to ensure peak performance your system must be properly maintained Clogged filters and blocked airflow prevent your unit from operating at its most efficient level NOTE The ...

Page 15: ...ure Supply Air Temperature Ambient Temperature Return Air Temperature System Refrigerant Charge Refer to manufacturer s information on unit or installation instructions for required subcooling and approach temperatures Subcooling A B SUBCOOLING Saturated Condensing Temperature A minus Liquid Line Temperature B Approach A B APPROACH Liquid Line Temperature A minus Outdoor Air Temperature B Indoor C...

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