Refrigerant is any substance used to transfer heat from one area to another. Modern air conditioners use a blend of hydro-fluorocarbons called R-410A, a non-combustible gas that quickly shifts from one state to another. Older air conditioners use Freon, also known as R-22.
In the 1970s, researchers discovered Freon damaged the ozone layer. As a result, the United States banned its manufacture and import. Older units may still use it, but they have to use Freon recycled from other systems. Consequently, most Freon units have been replaced with ones powered by R-410A.
How Refrigerant Helps Your AC
Now that we know what refrigerant is, we can examine how it’s used in your air conditioner. First, it’s important to understand how it absorbs and transfers heat. In science class, we learned there are three states of matter: solid, liquid, and gas. When a substance (e.g. water) moves from one state to another, it gains or loses heat. If we heat ice, it becomes water and then vapors. If we lower the temperature, the vapor reverts back into water and then into ice.
But while it takes water a long time to cycle through these states, compounds like R-410A can move through them quickly. And they boil at an incredibly low temperature, which makes them ideal for transferring energy.
Refrigerant in Action
Once you understand the basics of refrigeration, it’s easy to see how refrigerant helps your air conditioner. Every air conditioner is made up of two halves: an evaporator and a condenser. The evaporator is a low-pressure system, while the condenser is a high-pressure system.
The refrigerant starts as a liquid in the condenser. The high pressure forces it through the condenser coils to the expansion valve. As it passes through the valve into the evaporator, the pressure on the refrigerant decreases, lowering its temperature well below 0°F.
Because energy flows from areas of high concentration to areas of low concentration, the refrigerant rapidly absorbs heat from the surrounding air and vaporizes. (Refrigerants such as R-410A and R-22 have an extremely low boiling point: approximately -55°/-41°F respectively.)
This vapor is drawn back into the condenser, where it is pressurized and converted back into liquid. In the process, its temperature is raised above 100°F and the extra heat is discharged through the condenser coils into the outside air. )Pressurized liquids have a high boiling point, which is why refrigerant doesn’t vaporize inside the condenser.) Then, due to the pressure exerted by the condenser, the refrigerant is forced back through the expansion valve and the cycle repeats.
How to Replace Refrigerant in Your AC
As long as it’s working properly, the refrigerant in your air conditioner never needs replacing. If the unit springs a leak, however, refrigerant levels will gradually fall until the unit can no longer function. Common signs include:
- Vents blowing warm air
- Ice accumulating inside your air conditioner
- Hissing or bubbling sounds inside your air conditioner
- Water pooling beneath the unit
- Rising electricity bills
Inhaling refrigerants can also cause serious medical problems, such as dizziness, nausea, and shortness of breath. Therefore, if you suspect your air conditioner is leaking, call a technician immediately. Once they’ve repaired the leak, it will be safe to replace the refrigerant. (Recharging a leaky air conditioner can damage it.)
Because refrigerant is dangerous if handled improperly, it can only be sold to certified technicians and only homeowners with the proper training are permitted to recharge their units. You will also need to purchase the right refrigerant. While most home air conditioners use R-410A, there are several others besides R-22. Check your owner’s manual to find out which refrigerant your unit requires.
When working with refrigerants, it’s always important to take safety precautions. Wear goggles, rubber gloves, and a respirator to protect your skin and lungs. Check the temperature outside as well. Refrigerants like R-410A are drawn toward cold environments. As a result, if the temperature is less than 55°F, the refrigerant won’t flow into your air conditioner.
Recharging Your Air Conditioner
Once you’ve bought the refrigerant and assembled your safety materials, it’s time to recharge your unit. The first step is to:
- Cut the Power to the Unit. Don’t just shut it off. Disconnect power at the fuse box or circuit breaker.
- Attach the Gauges and Valve Connections. There will be three lines connected to the refrigerant gauges. The blue one connects to the low-pressure side (thick pipe), while the red connects to the high-pressure side (thin pipe). Leave the yellow one for now. It connects to the refrigerant tank.
- Turn Your AC Back On. Restart the power and wait fifteen minutes. The refrigerant needs to stabilize before you can get a good reading.
- Hook the Refrigerant to the Valve Connections. R-410A tanks need to be upside down for the refrigerant to flow properly. Once your tank is properly positioned, open the valve to start adding refrigerant to your system.
- Open the Low-Pressure (Blue) Valve. To avoid overfilling your air conditioner, open the valve intermittently for only a minute or two at a time. Then shut it off and wait for the refrigerant to stabilize. When the gauges have stopped moving, open the valve again.
- Wait for the Gauges to Reach the Optimal Subcooling Temperature. Subcooling is the difference between the temperature of the refrigerant as it leaves the condenser and the temperature when it converts into a gas (i.e. its saturation temperature). If it’s too low, your lines will freeze. Once again, consult your owner’s manual for the optimal subcooling temperature.
- Disconnect the Refrigerant. Close the valves and disconnect the hoses, but leave your air conditioner running so you can perform a leak test. There are several methods, but electronic leak detectors are the most reliable.
Trust Homesential with Your Air Conditioner
Understanding what refrigerant is, how it works, and when to replace it is important for homeowners worried about managing temperatures inside their homes. In order to protect our customers, Homesential works with certified local technicians who can respond quickly when air conditioners malfunction. They’re qualified not only to repair cooling systems but also to replace refrigerants when they run low, without any hassle or headache.
What’s more, by bundling coverage, you lower your costs. Stop paying out of pocket when breakdowns occur. Protect your home and your finances by signing up for Homesential today.