Symptoms

Blower motor not running

The indoor blower does not operate when it should.

Blower motor continuously running

The indoor blower never shuts off.

Condensate pump not working

The pump does not remove condensate, or the safety switch opens the circuit.

Poor airflow

Low air delivery at registers, or low measured system airflow.

High static pressure

Measured external static pressure exceeds the equipment's rated range.

Water around the equipment

Standing water or drips near the air handler, furnace, or drain.

Rooms are unevenly heated or cooled

Some rooms are noticeably warmer or cooler than others.

Indoor humidity too high

The space feels damp and humidity stays above the target range.

Thermostat blank

The thermostat display is dark or unresponsive.

AC won't turn on

No outdoor unit operation on a cooling call.

AC runs but doesn't cool

Both units operate but the space temperature does not drop as expected.

AC freezes up

Ice forms on the evaporator coil, suction line, or both.

Outdoor fan not running

The compressor runs but the condenser fan does not.

Breaker trips

The equipment repeatedly trips its breaker, fuse, or disconnect.

Excessive noise

Abnormal mechanical, airflow, or electrical noise from the equipment.

Heat pump won't heat

The heat pump runs but provides little or no heating.

Heat pump won't cool

The heat pump runs but provides little or no cooling.

Heat pump won't defrost

Frost or ice builds on the outdoor coil and the defrost cycle does not clear it.

Furnace won't start

No response at all when there is a call for heat: no inducer, no ignition sequence, no blower.

Furnace won't ignite

The sequence begins but the burners never light, or ignition is attempted and fails.

Furnace short cycles

The furnace runs briefly and shuts down before satisfying the thermostat, then restarts.

Furnace blows cold air

The blower runs but supply air is cool or cold.

Furnace blower won't shut off

The indoor blower keeps running after the heat call ends.

Furnace locks out on a safety

A limit, rollout, pressure or flame-proving safety opens and the control locks out.

Boiler won't heat

The boiler does not fire, or fires without delivering heat to the zones.

Compressor won't start

The compressor hums, trips, or does nothing when energised.

High head pressure

Discharge/liquid-side pressure is above the expected range for conditions.

Low suction pressure

Suction pressure is below the expected range for conditions.

High suction pressure

Suction pressure is above the expected range for conditions.

Low superheat

Measured superheat is below the target range, risking liquid return to the compressor.

High superheat

Measured superheat is above the target range.

Low subcooling

Measured subcooling is below the target range.

High subcooling

Measured subcooling is above the target range.

Refrigerant leak

System charge is being lost; performance degrades over time.

Water heater not producing hot water

Little or no hot water at the fixtures.