Ducted Air Conditioning Problems: Zones, Airflow and Temperature Explained

The safe checks first

1. Controller settings. Mode, set temperature and which zones are open. It is common for a zone to have been closed on the controller and forgotten.
2. Return air filter. The large return grille has a filter behind it. If it is clogged, airflow drops everywhere. Clean or replace it as the manual describes if you can reach it safely.
3. Outlets. Are the ceiling or floor outlets open and not covered by furniture or rugs?
4. Power. Isolator at the outdoor unit and the circuit breaker.

Do not enter the roof space to inspect ductwork or open the indoor unit.

One zone not working

A zone motor or damper that has failed or stuck, a controller setting, or a wiring fault between the controller and the zone. If the zone was fine and has stopped, a zone motor is the usual suspect.

Weak airflow everywhere

A blocked return air filter, a dirty indoor coil, a fan problem, or ductwork that has collapsed, disconnected or been crushed in the roof. On systems that were connected to old ductwork, undersized or leaking ducts are a design fault rather than a breakdown, and no repair fixes that; see why new ductwork matters.

Not reaching temperature

Restricted airflow, a dirty outdoor coil, a refrigerant leak, a sensor reading the wrong place, or a system that was undersized for the house in the first place. We tell you which it is; an undersized system is a conversation about design, not a part.

Controller faults and error codes

Most ducted controllers show a code when they detect a fault. Note it down before you call; it tells our technician where to start.

What we do

A local technician diagnoses the actual fault and repairs it where practical on the day. We service and repair all major ducted brands, and we are factory-trained dealers for ActronAir and Rinnai. If the underlying problem is design rather than a component, we explain what a properly designed system involves: the MRGA Standard.