American Standard HVAC Mitsubishi Electric NAXSKS09A112A Series Manual

The American Standard HVAC Mitsubishi Electric NAXSKS09A112A Series is a high-efficiency split-system heat pump designed for residential and light commercial applications. This system features advanced inverter technology, multi-stage operation, compatibility with communicating thermostats, and meets ENERGY STAR® requirements. Below are key sections covering safety, features, installation, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. First-Time Setup & Commissioning 4. Technical Specifications 5. System Controls & Settings 6. Connecting Thermostat & Accessories 7. Operating Modes & Sequences 8. Maintenance & Service 10. Regulatory & Compliance Information 11. Troubleshooting Guide

Features at a Glance

Key components: Outdoor condensing unit with inverter-driven compressor, Indoor air handler or furnace coil, communicating control system, refrigerant lines, and electrical connections.

FeatureDescription
Inverter TechnologyVariable-speed compressor for precise temperature control and energy efficiency
Multi-Stage OperationProvides multiple levels of heating and cooling capacity
Communicating SystemFully compatible with American Standard AccuLink® communicating thermostats
High SEER/HSPF RatingsExceeds minimum efficiency standards for energy savings
Quiet OperationSound-dampening technology for reduced outdoor noise
Wide Operating RangeProvides heating performance in low outdoor temperatures
RefrigerantUses R-410A environmentally friendly refrigerant
Diagnostic CapabilitiesLED status lights and fault code reporting for service
Durability FeaturesCorrosion-resistant coating on coils and cabinet
WarrantyLimited warranty on compressor and parts

Installation Requirements

This equipment must be installed by a qualified HVAC technician in accordance with all applicable codes and the manufacturer's instructions.

  1. Site Selection: Choose a level, stable location for outdoor unit with adequate clearance for airflow and service access.
  2. Electrical Requirements: Connect to proper voltage and amperage circuit with dedicated disconnect. Follow National Electrical Code.
  3. Refrigerant Lines: Install correctly sized and insulated copper linesets. Ensure proper brazing and evacuation procedures.
  4. Condensate Drain: Install drain line from indoor unit with proper trap and slope away from structure.
  5. Indoor Unit Compatibility: Match with approved American Standard indoor coil or air handler.

WARNING! Installation by unqualified personnel or improper installation can result in equipment damage, personal injury, or death. Always follow safety procedures when handling refrigerant and electrical components.

First-Time Setup & Commissioning

After installation, the system must be properly commissioned for optimal performance.

  1. Power Up: Turn on power to indoor and outdoor units.
  2. Thermostat Configuration: Install and configure communicating thermostat per manual instructions.
  3. System Check: Verify proper refrigerant charge using subcooling/superheat method.
  4. Airflow Verification: Check indoor airflow and adjust blower speed if necessary.
  5. Test Operation: Run system in cooling and heating modes to verify proper operation.
  6. Customer Orientation: Explain basic operation, filter maintenance, and warranty registration.

CAUTION! Never operate system without proper refrigerant charge or with restricted airflow. This can cause compressor damage.

Technical Specifications

System Controls & Settings

Primary control is through the compatible communicating thermostat. The outdoor unit has diagnostic LEDs and DIP switches for configuration.

Thermostat Functions: Mode selection (Heat/Cool/Auto/Off), Temperature setpoint, Fan control (Auto/On), System status, Alerts, Scheduling, Advanced settings (if enabled).

Outdoor Unit DIP Switches: May be used to configure options such as thermistor type, defrost parameters, or communication addresses (consult installation manual).

Diagnostic LEDs: Flash patterns indicate normal operation, standby mode, or fault conditions. Refer to service manual for code interpretation.

Connecting Thermostat & Accessories

For full functionality, use an American Standard AccuLink® communicating thermostat.

  1. Turn off power to indoor unit at disconnect or circuit breaker.
  2. Remove old thermostat if present.
  3. Connect communicating wires between indoor unit and thermostat terminal block as per wiring diagram.
  4. Mount thermostat on wall and restore power.
  5. Follow thermostat setup wizard to configure for your system.

Tip: For non-communicating thermostats, conventional wiring can be used, but advanced features will not be available. Refer to the installation manual for conventional wiring diagrams.

Operating Modes & Sequences

The system automatically adjusts capacity based on indoor and outdoor conditions.

  1. Cooling Mode: Thermostat calls for cooling. Outdoor fan and inverter compressor ramp up to meet demand. Indoor blower circulates cool air.
  2. Heating Mode: Thermostat calls for heating. System reverses refrigerant cycle. Compressor and fans adjust to provide efficient heat.
  3. Auto Mode: Thermostat automatically selects between heating and cooling based on room temperature and setpoint.
  4. Defrost Cycle: In heating mode, the unit will periodically reverse to melting ice on outdoor coil. Fan may stop during this brief cycle.
  5. Fan Only: Circulates indoor air without heating or cooling.

WARNING! Do not switch between heating and cooling modes rapidly. Allow several minutes between mode changes to protect the compressor.

Maintenance & Service

Regular maintenance is essential for efficiency, performance, and longevity.

CAUTION! Always turn off electrical power before performing any maintenance. Do not attempt to service refrigerant circuit; this must be done by a certified technician.

Regulatory & Compliance Information

This product complies with applicable U.S. safety and performance standards. It is designed for use in the United States and Canada. The refrigerant used (R-410A) has zero ozone depletion potential (ODP). Installation must comply with local building codes, the National Electrical Code (NEC), and EPA regulations regarding refrigerant handling. This equipment may be covered by one or more patents. For warranty details, refer to the warranty certificate included with the product or contact American Standard. For technical support or to locate a dealer, visit www.americanstandardair.com or contact American Standard Heating & Air Conditioning.

Troubleshooting Guide

SymptomPossible CauseCorrective Action
System not turning onPower loss, tripped breaker, thermostat issueCheck circuit breaker/disconnect. Ensure thermostat has power and is set correctly.
Inadequate cooling/heatingDirty filter, blocked coils, low refrigerantReplace air filter. Clear debris from outdoor unit. Contact technician for refrigerant check.
Outdoor unit fan not runningObstruction, faulty motor, capacitorTurn off power and clear any obstruction. Contact technician.
Ice on outdoor coil (heating mode)Normal defrost cycle or faulty defrost controlIf ice persists for more than 1 hour, system may need service.
Unusual noisesLoose parts, debris in fan, compressor issueTurn off system and inspect for loose panels or debris. Contact technician if noise continues.
Water leakage indoorsClogged condensate drainClear drain line and ensure proper trap.
LED fault code flashingSystem error detectedNote flash pattern and consult service manual or contact technician.

Reset: Turning power off for 5 minutes may clear temporary faults. For persistent issues, contact a qualified service technician.

Service: For warranty service or technical assistance, contact an authorized American Standard dealer or visit www.americanstandardair.com.

American Standard HVAC Mitsubishi Electric NAXSKS09A112A Series Manual © - All Rights Reserved 2025