Trouble Shooting

Air Conditioning Trouble Shooting

If you have trouble with your air conditioning system try some of these troubleshooting ideas.

Still got issues?  Give Aeromac a call on 1800 333 503 or Book a Fault Call

Unit Fails To Start

First step is to always check the circuit breaker in the switch board is on and also there may be an isolator adjacent to the outdoor unit (condenser) that must also be switched on.
Are the batteries in the remote controller still charged? Test with fresh batteries.
The Daikin systems have protection devices built in that will prevent the unit from operating if the system goes out of its operation parameters. If this happens, the system may shut down and not restart. If this happens, go to the outside condensing unit and turn off the electrical isolator that is adjacent to the condenser or at the switchboard circuit breaker marked “Air Conditioner” or “AC”

Leave the switch in the ‘OFF’ position for 5 minutes, then turn it back to ‘ON’. In most cases this will resolve the issue.
However, if the unit does not start, a code may come up on the screen such as ‘U4’. Please take note of this code and ring our office on 1800 333 503 and we will get a technician to attend site.

Water Issues

During winter, the outdoor unit produces water, this is perfectly normal operation.
There is a small pipe around 20mm in diameter that protrudes through your facia. This is from a safety tray that is located under the air conditioning unit in the ceiling space. This pipe should NEVER flow. If you ever see water dripping from this safety drain, please turn your machine off and contact the office immediately on 1800 333 503.

If you notice a water stain on the ceiling, please turn your machine off immediately and contact the office on 1800 333 503.

Have you cleaned the filters?

Have you got the temperature set too low? (Below 21 degrees)

Is the Drain pipe blocked?


If the return air grille is noisy, it is usually an indication that the filter is dirty and needs to be cleaned. You can do this be vacuuming it or by rinsing it under water and letting it dry. We recommend you clean your filter(s) at least once a month.
If the registers are noisy, please refer to the ZONING section below.

Unit Runs But Won’t Heat / Cool

The system is a reverse cycle unit, meaning it heats and cools. However, you need to be sure that you have it set to the correct MODE.
If it is the warmer months, ensure the MODE is selected to “COOL”, and set the desired temperature.
In the cooler months select the MODE to “HEAT”, and set the desired temperature.

If, for example, it is July and you want to heat your home, and the MODE is set to “COOL”, it doesn’t matter if the temperature is set to 30 degrees, it will not heat while in “COOL” MODE. You need to the change the setting to “HEAT”. The reverse of this applies for the summer months, i.e., the system needs to be in “COOL” MODE.


Your home is divided up into zones, usually you will have a constant and a number of selectable zones. The number of zones that can be selected on vary depending on the home and the size of the system installed.
A good way to tell if the right number of zones are selected on is if there is a noise coming from the air ‘rushing’ through the supply vents, then you need to increase the number of zones selected. Alternatively, if the home is taking a long time to cool down or heat up, then reduce the number of zones selected on.