Installation Guidelines for Four-Way Reversing Valves

Installation Guidelines for Four-Way Reversing Valves

(Key Component in Refrigeration/Heat Pump Systems)

1. Pre-Installation Preparations

(1) Valve Model Verification

• Confirm valve model, coil voltage, and pipe dimensions match system specifications to prevent switching failure or leakage .
• Cross-check port labels on valve body: D (High Pressure), E (Low Pressure), S (Compressor Suction), C (Compressor Discharge) 

(2) Pipeline Cleaning

• Purge pipes with nitrogen before welding to remove debris, moisture, and oxide scales. Contaminants may cause valve jamming .
• For old valve replacement: Thoroughly clean residual refrigerating oil and welding slag.

(3) Electromagnetic Coil Protection

• Never energize coils before installation to avoid burnout.
• Remove coils or wrap with wet cloth during welding (coil insulation degrades above 120°C) .

2. Welding & Installation Critical Points

(1) Welding Operations

• Nitrogen Purging Welding: Inject nitrogen (0.02–0.05MPa) during welding to prevent internal oxidation .
• Controlled Heating Time: Use low-melting-point solder (e.g., silver-copper alloy) for rapid completion. Excessive heat deforms seals.
• Natural Cooling: Air-cool valve body to room temperature. Do NOT use water/refrigerant for forced cooling .

(2) Orientation & Positioning

• Vertical Installation Mandatory: Install valve upright (coil upward) to prevent gravity-induced spool misalignment .
• Avoid Vibration Sources: Keep away from compressors/fans to eliminate mechanical interference.
• Maintenance Accessibility: Reserve space for future coil/valve replacement .

3. System Commissioning Procedures

(1) Pre-Energization Checks

• Verify system vacuum ≤500μm to exclude air/moisture affecting spool movement.
• Ensure coil voltage (typically AC220V or DC24V) matches power supply .

(2) Reversing Test

• Manually switch modes post-startup (via controller or signal jumper). Listen for audible "click".
• No-Switch Troubleshooting:
  • Power failure (no voltage/undervoltage to coil).
  • Insufficient pressure differential (low refrigerant charge or blockage).
  • Spool jamming (overheating/contaminants during welding) .

(3) Operational Monitoring

• Observe high/low pressure stability during switching. Abnormal fluctuations indicate internal leakage.
• In heating mode: Check outlet pipe temperature. Cross-leakage between high/low pressure reduces efficiency .