Why does the ac give off cold air and then warm for some time and then again cold

If your car AC blows cold then warm, the cause can be a low system charge, moisture in the system, a malfunctioning expansion valve, clogged evaporator fins or an overcharge condition.

Frozen Evaporator Coils

When moisture collects on the evaporator coils, they may freeze. Frozen coils prevent heat transfer, so you’ll feel warm air blowing from your AC system if this problem is present. … Frozen evaporator coils can be caused by poor airflow, refrigerant leaks, system damage, or other issues.

Leaking or Low Refrigerant

If your central AC is not blowing cold air, the refrigerant may be the problem. The unit could be running low and need additional refrigerant added. The most likely cause of this is a leak. … If you suspect a refrigerant leak, you should contact an HVAC professional right away.

Your AC system is low on refrigerant. Since the AC compressor is driven by the engine, it doesn’t pump as much refrigerant when you’re at a stop or driving slowly. If the system is low on refrigerant, it will show up as AC blows warm at idle and blows colder when the engine is running at higher RPMs.

Low Refrigerant Levels and Other Possible Culprits

A central air conditioning system that is leaking refrigerant will make it more likely to notice intermittent cold air. … Other possible reasons for fluctuating cold air include: A damaged or sluggish blower motor. Dirty coils.

Try cleaning your air conditioner’s filter and the coils to see if improving the airflow fixes the problem. If there is ice buildup, you’ll need to run the unit with just the fan in order to melt it off. If that doesn’t get the unit blowing cold air again, it could be refrigerant levels are low (see below).

Your Air Filter Is Dirty

Clogged air filters could be causing cold air to blow out of your vents. A dirty air filter can block airflow over your furnace’s heat exchanger, which can cause it to overheat.

An AC’s reset button is typically red and visible, so it should be easy to spot. If you don’t see a reset button on the outside, it could be located inside the unit behind the service panel. Before poking around inside the machinery, be sure to cut power to the system by flipping off your circuit breaker.

Top Reasons Your AC Compressor Stopped Working

Dirty condenser coils. Blocked suction lines. Low refrigerant charge. … Too much refrigerant.

Anytime you suspect an issue with your HVAC system, resetting the thermostat should be your first course of action. Like personal electronics such as tablets and phones, sometimes these devices need a reset.

Test the load: If you saw a voltage reading during the previous step, run the same test on the “load” side of the fuses. You should again see a reading between 220 and 240. If you see a voltage reading on the “line” side but not the “load” side, it means you have a blown fuse.

The function of the AC compressor

An air conditioning unit can still appear to run with a malfunctioning HVAC compressor. AC unit is equipped with a pair of fans, which still can run even in case of a malfunctioned compressor.

But perhaps the simplest method is the “odor test.” The smell that comes when a hose is connected to the system is both pungent and revealing. Once sniffed, it’s never forgotten and is one of the best indicators of a compressor burn-out.

When the ac compressor not working but the fan is running, chances are the outer unit housing the compressor isn’t receiving power. The fan keeps running because the central unit has no such problem. … Other potential causes may include a faulty thermostat, mismatched indoor and outdoor units, or the AC may just be old.

It means that the coolant isnt getting to the right temperature. Usually caused by the coil aging and not enough air going over it…or the compressor not compressing enough. Both are expensive repairs and usually mean the need for a new AC unit.

The short answer is that your AC compressor and refrigerant should last about 12-15 years. Learning what crucial components, and how to maintain the compressor, can keep your AC running efficiently for its entire lifespan.

Some common causes of compressor overheating are lack of external cooling, poor ventilation, short cycling, low suction pressure, high head pressure, lack of lubrication, excessive wear and tear, and electrical problems.