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508133G01 / 31-5000715

Page 7 of 25

Issue 2140

5.  Disconnect the liquid line from the expansion valve at 

the liquid line assembly.

6.  Disconnect the expansion valve from the liquid line 

orifice  housing.  Take  care  not  to  twist  or  damage 

distributor tubes during this process.

7.  Remove and discard expansion valve and the two 

Teflon

®

 rings.

8. 

Use a field-provided fitting to temporarily reconnect the 

liquid line to the indoor unit’s liquid line orifice housing.

Connect Gauges and Equipment for Flushing 

Procedure

LOW

HIGH

EXISTING

INDOOR

UNIT

GAUGE

MANIFOLD

CYLINDER CONTAINING

CLEAN R-410A 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

VAPOR LINE

SERVICE VALVE

VAPOR

LIQUID

1

1

2

3

4

Figure 5. Connecting Gauges

1.  Cylinder with clean R-410A (positioned to deliver liquid 

refrigerant) to the vapor service valve.

2.  Refrigerant gauge set (low side) to the liquid line valve.
3.  Refrigerant gauge set center port to inlet on the 

recovery machine with an empty recovery tank 

connected to the gauge set.

4.  Connect recovery tank to recovery machine per 

machine instructions.

Flushing Line Sets

If the unit will be installed in an existing system that uses 

an indoor unit or line sets charged with R-22 refrigerant, 

installer must perform the following flushing procedure.

NOTE: 

Existing  system  components  (including  line  set 

and indoor coil) must be an AHRI match with the unit in 

order to fulfill unit warranty requirements.

Fire, Explosion and Personal Safety 

hazard. Failure to follow this warning 

could result in damage, personal injury or 

death.

Never use oxygen to pressurize or 

purge refrigeration lines. Oxygen, when 

exposed  to  a  spark  or  open  flame,  can 

cause fire and/or an explosion, that could 

result in property damage, personal injury 

or death.

 WARNING

When using a high pressure gas such as 

nitrogen to pressurize a refrigeration or air 

conditioning system, use a regulator that can 

control the pressure down to 1 or 2 psig (6.9 

to 13.8 kPa).

 WARNING

Refrigerant must be reclaimed in accordance with 

national and local codes.

 WARNING

1.  Set the recovery machine for liquid recovery and start 

the recovery machine. Open the gauge set valves to 

allow the recovery machine to pull a vacuum on the 

existing system line set and indoor unit coil.

2.  Position the cylinder of clean R-410A for delivery of 

liquid refrigerant and open its valve to allow liquid 

refrigerant to flow into the system through the vapor 

line valve. Allow the refrigerant to pass from the 

cylinder and through the line set and the indoor unit 

coil before it enters the recovery machine.

3.  After all of the liquid refrigerant has been recovered, 

switch the recovery machine to vapor recovery so 

that all of the R-410A vapor is recovered. Allow the 

recovery machine to pull the system down to 0.

4.  Close the valve on the inverted R-410A drum and the 

gauge set valves. Pump the remaining refrigerant out 

of the recovery machine and turn the machine off.

Summary of Contents for NS18HMA

Page 1: ...ion and service performed by unqualified persons can result in property damage personal injury or death WARNING Sharp metal edges can cause injury When installing the unit use care to avoid sharp edge...

Page 2: ...ll safety codes Wear safety glasses and work gloves Use quenching cloth for brazing operations Have fire extinguisher available Read these instructions thoroughly and follow all warning or cautions at...

Page 3: ...m building not to exceed 1 4 per foot Figure 1 Slab Mounting Install on a Solid Level Mounting Pad The outdoor section is to be installed on a solid foundation This foundation should extend a minimum...

Page 4: ...warranty will be void if the drier is not installed Installation of Line Sets DO NOT fasten liquid or suction lines in direct contact with the floor or ceiling joist Use an insulated or suspension typ...

Page 5: ...listed in Table 3 Between 51 and 150 Linear Feet Crankcase heater and nonbleed port TXV factory installed No additional components required Vertical vapor riser must be sized to the vapor riser liste...

Page 6: ...iquid line size shaded row on the outdoor tonnage C Select the actual Total Linear Length of your system shown at the top of the table D The elevation listed in the table is the maximum allowed for th...

Page 7: ...ponents including line set and indoor coil must be an AHRI match with the unit in order to fulfill unit warranty requirements Fire Explosion and Personal Safety hazard Failure to follow this warning c...

Page 8: ...around the stubbed end of the check expansion valve and lightly lubricate the connector threads and expose surface of the Teflon ring with refrigerant oil 4 Attach the stubbed end of the check expans...

Page 9: ...ain round Do not crimp end of the line Remove service cap and core from both the vapor and liquid line service ports 1 2 LIQUID LINE SERVICE VALVE SERVICE PORT CORE SERVICE PORT CAP SERVICE PORT CORE...

Page 10: ...all water saturated 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 brazin...

Page 11: ...sig 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...

Page 12: ...r 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 Close manifold gauge valves Shut off HFC 410A cyli...

Page 13: ...1 is jumpered to Y2 in the outdoor unit Note that the published performance data is based upon the use of a two stage thermostat Refer to the NS18HMA field wiring diagram for a conventional 24VAC sing...

Page 14: ...hermostat Control Options Size Circuit and Install Service Disconnect Switch Refer to the unit nameplate for minimum circuit ampacity and maximum fuse or circuit breaker HACR per NEC Install power wir...

Page 15: ...100 30m 18 Temperature Rating 35 C Minimum More than 100 30m 16 Table 7 Conventional 24VAC Thermostat Wiring Route High Voltage and Ground Wires Any excess high voltage field wiring should be trimmed...

Page 16: ...RMOSTAT W L Y2 Y1 O DS C I I R DF TST Y1 O C W1 R G TC TO ACC2 ACC1 Y1 O DH C W2 W1 R G DS W2 FOR SINGLE STAGE OPERATION INSTALL A JUMPER BETWEEN Y1 TO Y2 ON THE OUTDOOR UNIT TERMINAL STRIP Figure 9 C...

Page 17: ...If the intended capacity for the application is 3 or 5 Ton skip this section The units are field convertible to 2 Ton or 4 Ton to efficiently perform for the required application If the intended capa...

Page 18: ...itiate the Charge Mode A heating blower demand must also be provided to initiate high speed blower operation on the indoor unit The compressor and outdoor fan motor will begin to ramp up and reach 100...

Page 19: ...ooling indoor blower operation In single stage thermostat applications a jumper must be installed between Y1 and Y2 on the NS18HMA outdoor control The compressor will be controlled in the variable cap...

Page 20: ...late to list the actual field charge Table 11 Refrigerant Charge Adjustment Liquid Line Set Diameter Oz Per 5 ft adjust from 15 ft line set 3 8 in 3 oz per 5 ft or 0 6 oz per 1 ft If line length is gr...

Page 21: ...testing is completed replace service port cap Tighten finger tight then an additional 1 6 turn To Open Liquid or Suction Line Service Valve 1 Remove stem cap with an adjustable wrench 2 Use service wr...

Page 22: ...in mild detergent and rinsing with cold water Allow filter to dry before reinstalling Replace filters with the arrows pointing in the direction of airflow Dirty filters are the most common cause of p...

Page 23: ...heat pump to automatically switch from heating mode to cooling mode to maintain predetermined comfort settings Many heat pump thermostats are also equipped with an emergency heat mode which locks out...

Page 24: ...Page 24 of 25 508133G01 31 5000715 Issue 2140 Figure 15 Wiring Diagram...

Page 25: ...____________ Actual Amps ______ Rated Volts _______ Actual Volts ________ Condenser Fan Full Load Amps _________ Actual Amps ______ Cooling Mode Suction Pressure ____________________ Liquid Pressure _...

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