UncategorizedMarch 18, 2023by Alex

Why does the air conditioner hum and what to do about it?

It is much easier, more convenient, and more profitable to prevent the breakdown, having taken the necessary measures in time, than to eliminate the consequences afterward. The first sign that your climatic equipment needs an inspection and operative troubleshooting is the uncharacteristic noise. Modern split systems, more often used in life, in offices and small stores, consisting of 2 blocks:


– Indoor.

– Outdoor (located outside the room on the street).


When installing a new air conditioner service staff checks the normal functioning of the equipment. But in some time after the natural wearing of details, the influence of unfavorable factors, untimely or low-quality service, in different parts of the air-conditioner appears defects. Exactly about them the hum signals.


Causes of hum in the internal unit


Noise and loud, disturbing humming noise in the split-system indoor unit, as a rule, is the first thing that draws your attention. The humming noise can be both in switched on and switched off state.


If there is an abnormal humming noise coming from the working conditioner, the matter can be in the following:


– The fan assembly is defective. Loud noise from the fan can come from the bearing wear (it is necessary to lubricate or replace it), deformation of plastic parts (with time it is possible in cheap Chinese models), presence of freeze or big accumulation of dirt and debris inside the unit.

– The electric motor is defective. The most common cause of the noise is an inter-turn short circuit in the winding. It is necessary either to replace only the winding or the complete motor (depending on the specifics of the model).


The humming of the air conditioner when it is switched off is evidence of problems with the transformer, which feeds the control board. The way out is – replacement, the good thing is that it is inexpensive.


Causes of humming in the outside unit


The outside unit of the conditioner, placed outdoors, lets out a certain noise, which is naturally drowned by the noise from the street. There is no discomfort at this. But, sometimes, the humming noise can become so strong that it is impossible not to pay attention to it. The most common cause of increased noise is a malfunction in the compressor:


– A drop in resistance on the windings.

– Natural wear and tear and failure of vibration isolation mounts.

– Rapidly reduced oil level in compressor crankcase.


For exact detection and elimination of troubles, as for installation of air conditioner, it is better to call for service masters, because even adding oil is done according to a certain technology with a special tool, as well as depending on the model of air conditioner and brand of freon used.


Besides problems with the compressor unit, the reason for the high humming of the split-systems external block can become a fan and its bearing. As in the case of the indoor unit, troubleshooting, as a rule, consists of the replacement of the damaged part.


Don’t delay your air conditioner repair. Do not forget that repairing is much easier and cheaper immediately after a breakdown occurs. If your air conditioner is working, but making strange noises or not cooling the room enough, it means it’s time to contact the technicians.


Don’t wait until the air conditioner is completely out of order. In the case of untimely repairs, there is a very high possibility that a long complex repair will be required. Even a few days without air conditioning in the summer heat in San Diego County, CA will bring great discomfort to the whole family. But by calling the masters from SDAC Heating & Air Conditioning you can avoid this problem.


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(858) 788-1-777


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