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508133G01 / 31-5000715

Issue 2140

General

Read this entire instruction manual, as well as the 

instructions supplied in separate equipment, before 

starting the installation. Observe and follow all warnings, 

cautions, instructional labels, and tags. Failure to comply 

with these instructions could result in an unsafe condition 

and/or premature component failure.

These instructions are intended as a general guide only 

for use by qualified personnel and do not supersede any 

national or local codes in any way. The installation must 

comply with all provincial, state, and local codes as well as 

the National Electrical Code (U.S.) or Canadian Electrical 

Code (Canada). Compliance should be determined prior 

to installation.

This unit uses R-410A, which is an ozone-friendly HFC 

refrigerant. The unit must be installed with a matching 

indoor coil and line set. A filter drier approved for use with 

R-410A is installed in the unit.

IMPORTANT

This product has been designed and 

manufactured to meet ENERGY STAR criteria for energy 

efficiency when matched with appropriate coil components. 

However,  proper  refrigerant  charge  and  proper  air  flow 

are  critical  to  achieve  rated  capacity  and  efficiency. 

Installation of this product should follow the manufacturer’s 

refrigerant  charging  and  air  flow  instructions. 

Failure to 

confirm proper charge and airflow may reduce energy 

efficiency and shorten equipment life.

Inspection of Shipment

Upon receipt of equipment, carefully inspect it for possible 

shipping damage. If damage is found, it should be noted 

on the carrier’s freight bill. Take special care to examine 

the unit inside the carton if the carton is damaged. Any 

concealed damage discovered should be reported to the 

last carrier immediately, preferably in writing, and should 

include a request for inspection by the carrier’s agent.

If any damages are discovered and reported to the carrier 

DO NOT INSTALL THE UNIT

, as claim may be denied.

Check the unit rating plate to confirm specifications are as 

ordered.

Safety Precautions

Follow all 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 attached to 

the unit.
1.  Always wear proper personal protection equipment.
2.  Always disconnect electrical power before removing 

panel or servicing equipment.

3.  Keep hands and clothing away from moving parts.

4.  Handle refrigerant with caution; refer to proper MSDS 

from refrigerant supplier.

5.  Use care when lifting, avoid contact with sharp edges.

Installation

NOTE: 

In some cases, noise in the living area has been 

traced  to  gas  pulsations  from  improper  installation  of 

equipment.

•  Locate unit away from windows, patios, decks, etc. 

where unit operation sounds may disturb customer.

•  Leave some slack between structure and unit to 

absorb vibration.

•  Place a sound-absorbing material, such as Isomode, 

under the unit if it will be installed in a location or 

position that will transmit sound or vibration to the 

living area or adjacent buildings.

•  Install the unit high enough above the ground or roof to 

allow adequate drainage of defrost water and prevent 

ice buildup.

•  In heavy snow areas, do not locate the unit where 

drifting snow will occur. The unit base should be 

elevated above the depth of average snows.

NOTE: 

Elevation  of  the  unit  may  be  accomplished 

by constructing a frame using suitable materials. If a 

support frame is constructed, it must not block drain 

holes in unit base.

•  When installed in areas where low ambient 

temperatures exist, locate unit so winter prevailing 

winds do not blow directly into outdoor coil.

•  Locate unit away from overhanging roof lines which 

would allow water or ice to drop on, or in front of, coil 

or into unit.

To prevent personal injury, as well as damage to panels, 

unit or structure, observe the following: 

While installing or servicing this unit, carefully stow all 

removed panels so that the panels will not cause injury 

to personnel, objects or nearby structures. Also, take 

care to store panels where they will not be subject to 

damage (e.g., being bent or scratched).
While handling or stowing the panels, consider any 

weather conditions (especially wind) that may cause 

panels to be blown around and damaged.

 WARNING

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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