This document is a service manual for Willis Air Conditioning units, specifically models WST18MC16S, WST18MH16S, and WST24MH16S. It provides comprehensive information for installation, operation, troubleshooting, and maintenance.
Function Description
The Willis Air Conditioning units are designed for both cooling-only and cooling & heating operations, depending on the model. They function by circulating refrigerant through an indoor evaporator and an outdoor condenser (or heat exchanger), facilitating heat exchange between the indoor and outdoor environments. The units employ a compressor, fan motors (for both indoor and outdoor units), and an expansion valve (electron expansion valve for 18K and 24K models) to manage the refrigerant cycle. The indoor unit features an air filter, swing motor for louver control, and a display for operational status and temperature settings. The outdoor unit is equipped with an axial-flow fan and a rotary compressor.
Important Technical Specifications
The manual details specifications for 18K (WST18MC16S, WST18MH16S) and 24K (WST24MH16S) models.
18K Models (WST18MC16S, WST18MH16S):
- Power Supply: 208/230V~, 60Hz, 1 Phase.
- Cooling Capacity: 18000 Btu/h (Min~Max: 4500~21000 Btu/h).
- Heating Capacity (WST18MH16S only): 23500 Btu/h (Min~Max: 4000~23500 Btu/h).
- Cooling Power Input: 1600W (Min~Max: 200~2600W).
- Heating Power Input (WST18MH16S only): 2400W (Min~Max: 300~2400W).
- Rated Input: 2600W.
- EER: 11.25 Btu/w.h (WST18MC16S), 11.11 Btu/w.h (WST18MH16S).
- COP (WST18MH16S only): 10.70 Btu/w.h.
- SEER: 16.00.
- HSPF (WST18MH16S only): 8.50.
- Application Area: 23-34 m².
- Indoor Fan Motor: Cross-flow type, Φ98X650mm, 20W output, 1.5µF capacitor.
- Outdoor Compressor: China Resources Sanyo (Shenyang), C-6RZ146H1A, Rotary type, FV50S oil.
- Outdoor Fan Motor: Axial-flow type, Φ520mm, 60W output, 3.5µF capacitor.
- Refrigerant: R410A.
- Refrigerant Charge: 1.20 kg (WST18MC16S), 1.25 kg (WST18MH16S).
- Piping: Liquid Pipe Φ6mm, Gas Pipe Φ12mm.
- Max Distance Height: 10m.
- Max Distance Length: 25m.
24K Model (WST24MH16S):
- Power Supply: 208/230V~, 60Hz, 1 Phase.
- Cooling Capacity: 22000 Btu/h (Min~Max: 6400~24000 Btu/h).
- Heating Capacity: 26600 Btu/h (Min~Max: 4100~26600 Btu/h).
- Cooling Power Input: 2200W (Min~Max: 300~2550W).
- Heating Power Input: 2800W (Min~Max: 320~2800W).
- Rated Input: 2800W.
- EER: 16.00 Btu/w.h.
- COP: 9.50 Btu/w.h.
- SEER: 27-42.
- Application Area: Not specified, but generally larger than 18K.
- Indoor Fan Motor: Cross-flow type, Φ98X765mm, 35W output, 2.5µF capacitor.
- Outdoor Compressor: China Resources Sanyo (Shenyang), C-6RZ146H1A, Rotary type, FV50S oil.
- Outdoor Fan Motor: Axial-flow type, Φ520mm, 60W output, 3.5µF capacitor.
- Refrigerant: R410A.
- Refrigerant Charge: 1.55 kg.
- Piping: Liquid Pipe Φ6mm, Gas Pipe Φ12mm.
- Max Distance Height: 10m.
- Max Distance Length: 25m.
All models feature Aluminum Fin-copper Tube evaporators and condensers. The outdoor units have an IP24 moisture protection rating.
Usage Features
The air conditioning units offer various operational modes and controls via a remote controller (YB1F2 model) and a manual ON/OFF button on the indoor unit.
- Operation Modes: AUTO, COOL, DRY, FAN, and HEAT (for heating models).
- Temperature Setting: Adjustable within 16~30°C (61~86°F).
- Fan Speed: Multiple settings including AUTO, Low, Medium, High, and Super High.
- Swing Function: Up & down swing and left & right swing for optimal air distribution. The remote controller allows switching between simple swing and static swing.
- X-FAN Function (Blow): Dries the indoor unit after cooling or dry mode operation to prevent mold.
- TIMER Function: Allows setting auto-on and auto-off timers.
- TURBO Function: Activates super high fan speed for rapid cooling or heating.
- SLEEP Mode: Adjusts temperature and fan speed for comfortable sleep.
- LIGHT Function: Controls the display light on the indoor unit.
- HEALTH Function: Selectable mode for enhanced air quality.
- Lock Function: Keypad lock on the remote controller.
- Temperature Display: Can display set temperature or ambient temperature in Celsius or Fahrenheit.
- Memory Function: Retains settings (mode, swing, light, temperature, fan speed, general timer) after power failure.
- Protection Functions: Includes current protection, drop-off voltage protection, IPM module protection, compressor overload protection, and various temperature sensor malfunction protections.
- Defrosting Control: Automatic defrosting in heating mode.
- Anti-cold Function: Prevents cold air blow in heating mode.
Maintenance Features
The manual provides detailed instructions for installation, troubleshooting, and removal procedures, emphasizing safety precautions.
- Safety Precautions: Strict adherence to local codes, proper grounding, tight wire connections, and use of specified refrigerant are highlighted to prevent injury, fire, electric shock, and property damage. Warnings are given against touching heat exchanger fins, compressor, or refrigerant piping without gloves due to extreme temperatures.
- Installation: Detailed steps for mounting indoor and outdoor units, boring wall holes, flaring pipes, connecting piping, and electrical wiring. Specific torque values for flare nuts and valve stem caps are provided.
- Test Operation: Procedures to check for normal operation, lamp functionality, louver movement, drain function, abnormal noise/vibration, and gas leakage after installation.
- Troubleshooting: A comprehensive section with diagnostic flowcharts and tables for various malfunctions, including:
- Temperature sensor malfunctions (indoor and outdoor).
- PG motor (indoor fan) malfunctions.
- Jumper cap malfunctions.
- Capacity charging malfunctions (outdoor unit).
- IPM protection, desynchronizing, and compressor overcurrent malfunctions.
- Anti-high temperature and overload protection.
- PFC (power factor correction) malfunctions.
- Communication malfunctions between indoor and outdoor units.
- Failure startup malfunctions.
- Voltage issues (DC bus-bar high/low).
- EEPROM malfunction.
- Charging malfunction of capacitor.
- Four-way valve abnormalities.
- Zero-crossing malfunctions.
- Resistance tables for ambient, indoor tube, and outdoor discharge temperature sensors are provided for diagnostic purposes.
- Discharging Method: Instructions for safely discharging large-capacity electrolytic capacitors in the outdoor unit controller to prevent electrical shock during maintenance.
- Refrigerant System Diagram: Detailed diagrams for cooling-only and cooling & heating models (18K and 24K) to aid in understanding the refrigerant flow and component layout.
- Exploded Views and Parts List: Detailed diagrams and lists of parts for both indoor and outdoor units, facilitating identification and replacement of components.
- Removal Procedure: Step-by-step guides for disassembling both indoor and outdoor units, including removal of panels, filters, electrical boxes, piping, fan motors, compressors, and other components. Emphasis is placed on waiting 10 minutes or more after turning off power before disassembly.
- Refrigerant Handling: Procedures for air purging, pumping down, re-air purging, evacuation, and gas charging, with specific instructions for connecting manifold gauges, vacuum pumps, and refrigerant cylinders. Cautions are given regarding gas leakage and proper refrigerant charging to avoid system damage.
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