What happens if subcooling is too high?

If the subcooling is too high, the system will be overcharged, reducing performance, efficiency, and ultimately damaging compressor valves and start components.

What does high subcooling indicate?

High Subcooling is an indication that more than the designed amount of refrigerant is “backing up” or “packed” into the condenser. This can be caused by overcharge, restriction (such as a contaminated line drier or kinked liquid line), or an undersized or failing closed metering device.

What effect does overcharging have on subcooling?

High condenser subcooling: Because of the overcharge of refrigerant in the system, the condenser will have too much liquid backed up at its bottom, causing high subcooling. Remember, any liquid in the condenser lower than the condensing temperature is considered subcooling.

How do you lower subcooling?

The temperature that you read with the thermometer should be lower than the saturated condensing temperature. The difference between the measured liquid line temperature and the saturated condensing temperature is the liquid subcooling. Add refrigerant to increase subcooling. Recover refrigerant to reduce subcooling.

What is the best subcooling for 410A?

Most heating and cooling systems should operate at a superheat of 10F at the evaporator and between 20F to 25F at the compressor. if your HVAC system has a thermostatic expansion valve (TXV), the subcooling should be between 10F and 18F.

Troubleshooting with Superheat and Subcooling (TXV)

Will a dirty condenser coil cause high subcooling?

Even the subcooled liquid temperature coming out of the condenser will be at a higher temperature when the condenser is damaged, fouled, or dirty.

What are the symptoms of an overcharged AC system?

The likely symptoms of an overcharged AC are poor cooling, no air coming out of the wents, weird noises from the engine bay, and check engine light turning on. Because the AC coolant is toxic, fixing an overcharged AC is a job for a professional AC mechanic.

What happens if you overcharged refrigerant?

Having too much refrigerant in your AC can damage the compressor. This can happen because the excess refrigerant will likely collect inside the compressor and cause subcooling, wherein temperatures are below normal. Furthermore, the extra refrigerant can flood the compressor and damage its mechanical parts.

What causes low superheat and high subcooling?

If superheat is high and sub-cooling is high: Could have blockage in coil, orifice or line set. If superheat is low and sub-cooling is low: Orifice could be too big, there is no orifice in the unit of the orifice is stuck and refrigerant is by-passing it. Superheat is telling you what is going on in the evaporator.

Is it worse to overcharge or undercharge?

Overcharging

While you certainly don't want to keep your battery in an undercharged state, overcharging is just as bad. Continuous charging can: cause corrosion of the positive battery plates.

How do you tell if your AC is undercharged?

How do I know if my 410a is overcharged?

What causes high superheat and high subcooling?

If you notice a high superheat and an excessively high subcooling, this is likely a system with a liquid line restriction that is overcharged. A previous technician has likely added pounds of refrigerant into the system in an attempt to raise the low side saturated temperature to a level above freezing.

What is the ideal superheat and subcooling?

“Typically” on TXV systems the Superheat will range between 8 to 28 degrees with a target of about 10 to 15 degrees. The Subcool range on TXV systems will range from about 8 to 20. Although this is not enough information to charge a system, it does give a technician a better understanding of the systems operation.

What is normal subcooling for r22?

Subcooling on systems that use a thermostatic expansion valve (TXV) should be approximately 10°F to 18°F. Higher subcooling indicates excess refrigerant backing up in the condenser.

Can too much refrigerant cause short cycling?

Watch out: an air conditioner or heat pump system that has been over-charged with refrigerant can also show up the problem as short cycling, rapid on-off cycling of the compressor motor.

What causes flooding and slugging?

As mentioned earlier, this is referred to as flooding. This causes oil foaming and excessively high crankcase pressures. Refrigerant and oil droplets will soon reach the compressor's cylinder and slugging will soon occur. Slugging in hermetic compressors can also occur from a migration problem.

Can you add too much refrigerant?

The Compressor: Excess refrigerant creates a danger called slugging. This is when extra refrigerant floods into the piston cylinders of the compressor when in a liquid state. Slugging can create many different problems such as broken valves, broken connecting rods, and significant damage to the compressor.

Will an AC freeze up if overcharged?

An over charged Txv system, will not directly cause an evaporator freeze up. At most it will result in excessive high head pressure, and reduce the compressors efficiency.

What are the signs of a dirty condenser coil?

What are the symptoms of a clogged condenser coil?

What are the symptoms of a dirty condenser?

What are normal operating pressures for 410A?

A normally operating R-410A system with the same condensing temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig.