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Page 9

14ACX SERIES

STEP 3 -- LEAK TEST AND EVACUATION

A -

With both manifold valves closed, connect the cylinder of HFC-410A refrigerant to the center port of the
manifold gauge set. Open the valve on the HFC-410A cylinder (vapor only).

B -

Open the high pressure side of the manifold to allow HFC-410A into the line set and indoor unit. Weigh in
a trace amount of HFC-410A.

 [A trace amount is a maximum of two ounces (57 g) refrigerant or three

pounds (31 kPa) pressure.] 

Close the valve on the HFC-410A cylinder and the valve on the high

pressure side of the manifold gauge set. Disconnect the HFC-410A cylinder.

C -

Connect a cylinder of nitrogen with a pressure regulating valve to the center port of the manifold gauge
set.

D -

Adjust nitrogen pressure to 150 psig (1034 kPa). Open the valve on the high side of the manifold gauge
set in order to pressurize the line set and the 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 -

Connect the high pressure hose of an HFC-410A manifold gauge set to the suction valve service
port.

NOTE 

- Normally, the high pressure hose is connected to the liquid line port. However, connecting it

to the suction port better protects the manifold gauge set from high pressure damage.

B -

With both manifold valves closed, connect the cylinder of HFC-410A refrigerant to the center port of
the manifold gauge set.

1

CONNECT GAUGE SET

2

TEST FOR LEAKS

NOTE

 - Later in the procedure, the HFC-410A container will be replaced by the nitrogen container.

LEAK TEST

TO SUCTION

SERVICE VALVE

(ANGLE OR BALL

TYPE)

HFC-410A

MANIFOLD GAUGE SET

OUTDOOR UNIT

HIGH

LOW

NITROGEN

A

B

FIGURE 10

Summary of Contents for Merit 14ACX-018-230

Page 1: ...tdoor air conditioner is designed for use with HFC 410A refrigerant only This unit must be installed with an approved indoor air handler or coil See the Lennox 14ACX Product Specifications bulletin EH...

Page 2: ...ing or stowing the panels consider any weather conditions especially wind that may cause panels to be blown around and damaged NOTICE Roof Damage This system contains both refrigerantand oil Some rubb...

Page 3: ...e rises above 40 psig DO NOT REPLACE COMPRESSOR LIQUID LINE FILTER DRIER INSTALLATION The provided filter drier must be field installed in the liquid line between the outdoor unit s liquid line servic...

Page 4: ...THE LIQUID LINE TO THE SUCTION 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 ext...

Page 5: ...ndoor 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 SER...

Page 6: ...d debur the ends The pipe must remain round Do not crimp end of the line Remove service cap and core from both the suction and liquid line service ports 1 2 ANGLE TYPE SERVICE VALVE SERVICE PORT CORE...

Page 7: ...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 clo...

Page 8: ...TION EQUALIZER LINE INSTALLATION A Remove and discard either the flare seal cap or flare nut with copper flare seal bonnet from the equalizer line port on the suc tion line as illustrated in the figur...

Page 9: ...door 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 gauge...

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 cylin...

Page 11: ...re only with this product CAUTION Failure to use properly sized wiring and circuit breaker may result in property damage Size wiring and circuit breaker s per Product Specifications bulletin EHB and u...

Page 12: ...t 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 Yellow to Y1 Black to C common R...

Page 13: ...ped with a service port which has a factory installed valve stem Figures 15 and 16 provide information on how to access and operate both angle and ball type service valves Torque Requirements When ser...

Page 14: ...he tables provided on the charging procedure sticker located on the unit access panel Detailed information is provided in the 14ACX Installation and Service Procedures manual Corp0638 L10 which is ava...

Page 15: ...as necessary 6 Inspect contactor contacts for pitting or burn marks Replace as necessary 7 Check outdoor fan motor for worn bearings bushings Replace as necessary 8 Inspect and clean outdoor coils if...

Page 16: ...re 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 appr...

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