Multi-Zone Ductless Heat Pump Piping — How It Works

Published: July 20, 2026 — BC Wide Home Services Ltd, doing business as BC Wide Heating & Air Conditioning — Greater Vancouver, BC

How Multi-Zone Works

A multi-zone system uses one outdoor unit connected to 2-8 indoor units. Refrigerant and power run through a line set to each indoor unit. The outdoor unit has a variable-speed compressor that modulates to match the total demand of all active indoor units.

Branch Box Systems

Some brands (Mitsubishi, Daikin) use a branch box — a central distribution point that directs refrigerant flow to each indoor unit. Branch box systems allow longer total line set runs and more flexible indoor unit placement. The branch box must be accessible for service.

Line Set Restrictions

Each manufacturer specifies maximum line set lengths. Typical limits: total system length 150-300 feet, maximum per indoor unit 50-100 feet, minimum per indoor unit 10 feet, and maximum elevation difference between indoor units 50 feet. Exceeding limits reduces performance.

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Safety Reminder

If you smell gas, suspect carbon monoxide or believe there is an immediate danger, leave the property and contact emergency services or the appropriate gas emergency authority. Do not remain inside — exit the building immediately and call for help from outside.