Fraser-Johnston Loss of Cooling / Reversing Valve or Charge Issue

The indoor unit blows warm air in cooling mode.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Reversing valve stuck in heat position (heat pump models), Low refrigerant charge, Failed compressor, Thermostat miswired (O/B signal incorrect)

Safety: Turn off power before accessing outdoor unit wiring.

Check mode: Confirm the thermostat is set to COOL and not HEAT or EMERGENCY HEAT.
Reversing valve signal: At the condenser, verify 24 VAC is present on the O/B terminal when in cooling (depending on system design). Correct thermostat wiring if misconfigured.
Observe outdoor unit: Ensure the compressor and fan are running. If only the fan runs, see compressor start failure steps.
Professional diagnosis: If the reversing valve is suspected of being stuck or the refrigerant charge is low, a technician must service the refrigerant circuit.

Hard 4/5

Reversing Valve

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