background image

Page 12

STEP 4 -- ELECTRICAL (CONTINUED) -- High Voltage and Field Control Wiring

The following illustration provide an example of control wiring connections when using standard thermostat.

Any excess high voltage field wiring should be
trimmed and secured away from any low voltage field
wiring. To facilitate a conduit, a cutout is located in the
bottom of the control panel. Connect conduit to the
control panel using a proper conduit fitting.

NOTE — Wire tie provides low voltage control wire strain
relief and maintains separation of field-installed low and
high voltage circuits.
NOTE — For proper voltages, select thermostat wire
(control wires) gauge per table above

.

NOTE — Do not bundle any excess 24VAC control
wires inside control panel.

Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit as illustrated.

A

Run 24VAC control wires through hole with grommet
and secure with provided wire tie.

B

Make 24VAC thermostat wire connections. Locate
the two wires from the contactor and make
connection using field-provided wire nuts:

S

Yellow to Y1

S

Black to C (common)

ROUTING HIGH VOLTAGE, GROUND AND CONTROL WIRING

WIRE RUN LENGTH

AWG#   INSULATION TYPE

LESS THAN 100' (30 METERS)

18      TEMPERATURE RATING

MORE THAN 100' (30 METERS) 16       35ºC MINIMUM.

HIGH VOLTAGE / GROUND WIRES

FIELD CONTROL WIRING

W1

Y

G

C

R

Y

G

C

THERMOSTAT

INDOOR UNIT

POWER

HEAT

COOLING

INDOOR BLOWER

COMMON

OUTDOOR UNIT

Y1

C

W

R

YELLOW

BLACK

FIGURE 14

STEP 5 -- UNIT START-UP

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.

1. Rotate fan to check for 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 listed on the unit's
nameplate. If not, do not start the equipment until you
have consulted with the power company and the voltage
condition has been corrected.

6. Connect manifold gauge set for testing and charging

using figure NO TAG as a guideline.

7. Set the thermostat for a cooling demand. Turn on power

to the indoor indoor unit and close the outdoor unit
disconnect switch to start the unit.

8. Recheck voltage while the unit is running. Power must

be within range shown on the unit nameplate.

9. Check system for sufficient refrigerate using the

procedures outlined in under

 System Refrigerant

.

OPERATING MANIFOLD GAUGE SET AND SERVICE
VALVES

The liquid and vapor line service valves are used for
removing refrigerant, flushing, leak testing, evacuating,
checking charge and charging.
Each valve is equipped with a service port which has a
factory-installed valve stem. Figure 15 provides information
on how to access and operating both angle and ball service
valves.

Torque Requirements

When servicing or repairing heating, ventilating, and air
conditioning components, ensure the fasteners are
appropriately tightened. Table 3 lists torque values for
fasteners.

IMPORTANT

To prevent stripping of the various caps used, the
appropriately sized wrench should be used and fitted
snugly over the cap before tightening.

When servicing or repairing HVAC components, ensure the
fasteners are appropriately tightened. Table 3 provides
torque values for fasteners.

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...

Reviews: