Fix / Split System AC — Outdoor Unit / Ice forming on pipes

AC (outdoor) ice forming on pipes?

An expansion valve stuck open allows too much refrigerant flow, causing excessive pressure drop and freezing of the suction line.

• Expansion Valve

  Call a Pro Part: $40–$120

• Condenser Coil

  Moderate DIY Part: $200–$500

  In heating mode, a dirty condenser coil acting as evaporator cannot absorb enough heat and freezes over prematurely.

• Four-Way Valve

  Call a Pro Part: $60–$180

  A leaking four-way valve bypasses hot discharge gas during defrost, preventing the coil from properly clearing ice.

• Control Board

  Moderate DIY Part: $100–$280

  A faulty control PCB may fail to initiate defrost cycles at the correct intervals, allowing ice to accumulate unchecked.

• Propeller Fan

  Moderate DIY Part: $50–$130

  A failed outdoor fan motor reduces airflow over the coil, causing surface temperatures to drop below freezing during operation.