However, even the most reliable of air conditioners may stop cooling or suffer from problems from time to time. Remember that one of the best ways to prevent unexpected A/C problems is to have regular maintenance performed on your unit. If you cannot perform the maintenance yourself, hire a professional to do so.
Inspect your unit's distribution channels. Make sure that the fan on your unit is kicking air into rooms or into your duct system.
If your unit turns on but doesn't cool, check your thermostat to be sure that it is set at the correct temperature. You should then check the condenser and evaporator for dirt and clogging. If too much dirt builds up, your unit may not turn on at all
Having a Hitachi unit turn on and off repeatedly is extremely frustrating. In general, this problem is caused either by a dirty condenser and fan or a clogged condenser.
If your condenser unit won't turn on at all, you may have a faulty motor or the unit may not be receiving power. Examine all wiring and ensure that the unit is plugged in.
If ice collects of your condenser coils or other portions of your unit, the Hitachi AC may not turn on or may not cool air efficiently. The unit must be dethawed and all ice must be removed before it will operate properly.
In most cases, your Hitachi A/C unit will shut down entirely if its motor is faulty. You will need to decide if your motor can be repaired or if it must be replaced.
Problems with your compressor may cause your Hitachi A/C unit to shut down. Keeping your compressor clean can help to prevent these problems.
If your Hitachi A/C unit doesn't have enough refrigerant, it may not turn on or may not operate correctly. You should always have a professional technician check refrigerant levels and change these fluids.