The air conditioning does not cool. What can I do?

The indoor climate depends on the quality of the air conditioning system. A good indoor climate has an impact on a person’s ability to work or on the level of comfort during relaxation.

The cooling function is the most important function of any air-conditioner. Unfortunately, there are many factors that reduce the quality of air-conditioning cooling. They often result in the equipment ceasing to cool the air at all. In such cases, a conditioner is no use at all. So what to do in such situations?

HVAC All Seasons Service Company in San Francisco Bay Area will make sure that your air conditioner will cool the air perfectly after a little air conditioning service. Our technicians will check your air conditioner for malfunctions. If your air conditioner is clogged, we’ll clean it, and if it’s broken, we’ll repair it. Give us a call and you’re guaranteed to get quality service at affordable prices in the San Francisco Bay Area. You can even apply from the comfort of your own home through our website or by calling +1 510 342 80 96

Is your air conditioner not cooling?

Diagnose an air conditioner in a flat in San Francisco

An air conditioner seldom malfunctions under ideal operating conditions. But ideal conditions are very rare nowadays – the equipment is always affected by negative factors, which even a man cannot always influence. In most cases they can be only minimized, but nobody is insured from failure of an air conditioner. Therefore, when the equipment malfunctions, it is necessary to check all causes, which can disturb the normal functioning, step by step by yourself.

Before looking for a fault in the air conditioner itself, check all the external factors that could disturb the operation of the equipment yourself. One of the following causes may be affecting the air conditioner’s normal cooling generation:

  • The start-up time of the air conditioning unit.
    The equipment does not start cooling immediately when it is switched on – you must wait 10-20 minutes, depending on the model, room size, air temperature and capacity of the equipment.
  • Ratio of air conditioner capacity to room parameters. Low-capacity air-conditioner is not able to cool rapidly a big premise, all the more so when the weather is very hot. When choosing air-conditioner, choose the model with reserve capacity, which would overcome the peak loads.
  • Block free air movement.
    Curtains and blinds, large furniture and various partitions prevent normal air circulation and its cooling.
  • Airtightness of the room.
    Air conditioning is less effective if the room is less airtight. Open windows, open doors and air intake and exhaust ventilation contribute to this. This is one of the main external factors that reduce the cooling capacity of the air conditioner.

If all of the above causes of cooling problems are eliminated but the room is not getting cooler, the cause is a faulty air conditioning unit. 

Cooling temperature diagnosis

For diagnosis, the temperature at the air conditioner’s inlet and outlet is measured. The temperature at the inlet is measured near the air inlet. To do so, place the thermometer on the housing or hold it in your hand near the air intake grilles. The outlet temperature is measured in the air stream coming out of the air conditioner. You can also slip the thermometer slightly in through the louvers. Be careful that the fan blades do not catch and break the thermometer.

Good conditioner has a difference of inlet and outlet temperatures in the range of 7-15 degrees. If you start air conditioner on a maximum cooling, and temperature difference is too low, it means that the reason is in internal malfunction. The outlet air temperature should be checked against the values, set by the manufacturer. This value is 6-14° for non-inverter air conditioners, the same for inverter air conditioners, but it rises to 12-17° a little later. If the air temperature is higher than the nameplate value, it indicates that the problem lies inside the air conditioner.

Possible faults, causes and remedies

1.The air conditioner works but does not cool

Cause: The fan mode is selected. The air conditioner just blows air without cooling it.

Solution: Switch on the cooling mode on the air conditioner.

2.The air conditioner cools the air weakly. The indoor unit is leaking or freezing.

Cause: Coarse and fine filters are clogged. Dust, hair, insects have built up a thick layer on the evaporator radiator, causing the cold air to escape poorly. The evaporator pipes frost up when heavily soiled. Dirt clogs the drain pipe, causing condensate to flow into the drip tray and then drip from the indoor unit.

Solution: Clean the air conditioning unit’s filters. To do this, open the cover of the unit. Wash the filters under cold running water. The filters must not be washed with hot water as they may become deformed due to the high temperature. For information on how to open the lid of the indoor unit, see the instructions for use of the air conditioning unit. If in doubt, consult a specialist.

3.The air conditioner does not cool well, the compressor in the outdoor unit is silent.

Cause: The radiator of the outdoor unit is dirty. Dust, leaves, insects, fluff accumulate on the heat exchanger and fan blades, causing the condenser heat exchange to deteriorate. Due to overheating, the automation is triggered and shuts down the compressor.

Solution: Clean the outdoor unit. Use a steam generator, a Kercher-type washing machine, a brush or a sponge. In a high-rise flat, the services of an industrial climber may be required.

4. Warm air comes out of the air conditioner. 

The compressor in the outdoor unit does not show any sign of life or switches on for 2 to 3 minutes, then switches off again.

Cause: The mains voltage is low. This causes the rotor winding to overheat and the motor is switched off by the thermal relay.

Solution: Install a voltage equalisation relay. This can either be fitted separately or in conjunction with a voltage regulator.

If the problems described above persist despite all efforts, the problem is deeper – the problem lies in the components and parts of the air conditioning system. If this is the case, a full system diagnosis and service will be necessary.

The air conditioner is not cooling in the room. Causes.


The problem: Often the air conditioner does not cool the air due to breakdowns, wear and tear or factory defects of parts and components. From experience, we have compiled a list of the most common faults and how professionals can rectify them.

Reason: The air conditioner blows well, but does not cool.

The air conditioner is low on freon. Even from a sealed circuit, up to 7 % freon may escape per year.

How to fix it: Partial or complete charging of the air conditioner with freon.


The problem: The air conditioner blows, but weakly or not at all. The compressor in the outdoor unit runs continuously, after which it switches off. On display models, a light comes on to indicate low pressure.

Reason: The system is depressurised, the freon has evaporated. As the refrigerant evaporates, the air conditioner shuts down less and less at rest. After a while, the air conditioner starts blowing room temperature air and the motor starts to run continuously. The pipe joints between the units are loose or the installation joints are leaking.

How to fix it: The point of leakage is established. Then the air tightness of the system is restored, moisture and air is removed from it. The air conditioning system is then charged with freon.


The problem: The air conditioner blows well, the compressor in the outdoor unit hardly ever shuts off. However, the air conditioner does not cool or cools very little. The pipe to the evaporator sometimes freezes.

Reason: The capillary pipe is clogged. This increases the pressure difference between inlet and outlet. As a consequence, part of the freon boils and gives up the cold without reaching the evaporator of the air conditioner. The system tries to compensate for the lack of cold generation by continuous operation of the compressor. If the pipe becomes completely clogged, the refrigerant stops circulating, the compressor runs idle and the air conditioner simply pumps warm air.

How to fix it: The blockage is eliminated by blowing out under pressure. Heavy blockages are eliminated by hydraulic cleaning and solvents. In particularly severe cases, the evaporation tube is removed and replaced with a new one.


The problem: The air conditioner blows, but hardly ever cools. The compressor in the outdoor unit switches off very rarely.

Reason:  The external air conditioning unit is clogged. Dust, soot, dry leaves and insects have settled on the heat exchanger. Dirt causes the fan speed to drop. Accumulated debris makes the outdoor unit lose excess heat to outside air, making it cooler. The air conditioner compensates for insufficient heat transfer by keeping the outdoor unit compressor running continuously.

How to fix it: The radiator of the outdoor unit is washed and cleaned. If the outdoor unit is difficult to reach, the services of an industrial climber may be required.


The problem: In cooling mode, the air conditioner blows hot air (on models that can operate in heating mode).

Reason:   The four-way valve responsible for changing between heating and cooling mode is broken. If it breaks, the valve is blocked in heating mode.

How to fix it:  The valve is repaired or replaced. Sometimes, if the customer does not need the heating mode, the faulty valve is simply removed. This procedure reduces the functionality of the air conditioning unit, but the repair is much cheaper and quicker.


The problem: The air conditioner cools the air, but poorly. The unit switches off almost immediately after being switched on, even when it is slightly cooler and the room is hot 

Reason:  Modern models have an error message

Thermistor or temperature sensor is defective. This is located in the indoor unit and monitors the temperature. If it malfunctions, it gives a low reading, which causes the air conditioner to shut down prematurely.

How to fix it:   Faulty evaporator or condenser temperature sensor. It is used to set the system pressure in accordance with the set cooling mode. Incorrect temperature causes the air conditioner to switch off prematurely.

Faulty temperature sensor is replaced with a new one.


The problem: The air conditioner blows, but cools weakly. The compressor in the outdoor unit runs non-stop and only switches off when the thermostat trips for overheating.

Reason:   The fan of the outdoor unit is broken. The motor may burn out due to dust ingress. This disturbs the heat exchange in the air conditioner, which causes the compressor to run continuously. The motor overheats and stops when the thermostat trips.

How to fix it:    A faulty fan or a faulty motor is replaced.

These are just the main faults; in fact, there are many more. To accurately determine the breakdown, an expert carries out a comprehensive diagnosis of the air conditioner. Based on its results, the volume and type of work is determined. The cost of the service is determined accordingly.

You can turn to our company for quality air conditioner repair – HVAC All Seasons