Edit ArticleHow to Charge a Home Air Conditioner Four Methods:Understand the Laws Regarding Working on an Air ConditionerCheck the SystemDetermine What You NeedRecharge Your ACCommunity Q&A One of the most expensive items on your electric utility bill in areas with hot summers is the cost of operating a central air conditioner. If your unit doesn't have the correct amount of refrigerant, this cost can be even higher. Here are some steps to help you charge your home central air conditioner. Know what it is legal for an unlicensed homeowner to do to their own equipment. Understand that a refrigeration supply company will not sell refrigerants or other regulated supplies to unlicensed individuals. Do not work on other individuals' air conditioning units for pay if you are unlicensed, you may be fined or face other legal actions for doing so. Perform routine maintenance first. Before you recharge your AC, it is very important that you perform standard maintenance on it.

Replace the air filter Clean the evaporator and condenser coils—if any of the above are dirty, it can cause symptoms similar to a unit that is low on refrigerant. If refrigerant is added under these conditions, the unit may be damaged. Check for any obstructions, including buildup of debris on the air handler blower fan and make sure the condenser fan is operating correctly. Conduct a thorough inspection of the rest of the components of your system. Determine the type of refrigerant you need for the AC system. Determine what type of charging connections your system is equipped with.quick connect Turn your air conditioner off at the thermostat.on/off Turn the power off on your air conditioning system. The outside unit should be equipped with a fused disconnect or circuit breaker located near the unit. Remove the fuses or turn the breaker off before continuing. With the AC unit off, hook up the gauges according to instructions. This will be with the low pressure side (the small hose/blue hose) on the gauges and the high pressure side of the system (the red hose).

Older manifold gauges may not have color coded hoses, usually, the low pressure gauge and connector is on the left facing the gauge, the high pressure is on the right, and the supply hose, which is connected to your refrigerant tank, evacuation pump, or other attachment, is in the middle.goodman 3 ton package unit price With the gauges hooked up, turn on the AC and wait 15 minutes for the system to stabilize.lowes ac units with heat Take a reading on the gauges. home air conditioner compressor runs intermittentlyThe blue gauge should have dropped if the system needs to be recharged. To verify this, use a temperature gauge with a probe attached to the low pressure side - or return line—which is the larger of the two lines.

Recharge if the temperatures on the blue gauge do not correspond to the number recommended in the equipment manufacturer's specifications. Use the site glass. Another way to determine if your system needs recharging is using the site glass on the unit. Many residential units are not equipped with site glasses, but if your unit has one, it will be on the outside of the unit on the return line between the inline dryer and the compressor. Once you have located the sight glass and cleaned the view port, look into it while the unit is running. See if there are bubbles mixed with the liquid refrigerant. A properly charged AC unit will be free of bubbles. You need to recharge the unit if there are bubbles mixed with the liquid coolant. Note that on a unit that has been improperly charged, bubbles may result from air or moisture trapped in the hermetically sealed refrigerant system. Take the following steps. Attach the hoses from the gauge manifold to your system's pressure ports.

The low pressure hose is normally blue and is connected to the suction line—the larger of the two pipes. The high pressure hose is generally red and is connected to the liquid line, which is the smaller of the two pipes. Turn on the AC.This will give you a comparative analysis of how the system is performing, with the following measurements: The outdoor air temperature The return air temperature at the furnace/air handler The suction line temperature The liquid line temperature Newer units will usually have a label inside the electrical cover with specific instructions for your unit. It will typically tell you to measure superheat or sub-cooling. It will also give you a chart that has values for superheat or sub-cooling for a given outdoor temperature. Determine your metering device. Check the charging procedure chart in your unit to determine what type of metering device your system uses. It will either be a thermostatic expansion valve or a restrictor orifice.

If your system uses a thermostatic expansion valve (TXV), use the following values: System superheat: 18°F (-7°C) System sub-cooling: 25°F (-4°C) If your system uses a restrictor, you can use the table below as a guide. It contains recommended superheat values for given indoor and outdoor air temps: To find the required superheat value, draw a line from the outside air temperature down to the return air temperature. The value in that row/column is the required superheat temperature.If the tests show that refrigerant is required, check for evidence of leaks and repair them. Leaks can typically be found around any joints or connections: Welded or brazed joints Any place where refrigerant lines may vibrate or rub against the unit chassis or other components. Connect the charging or supply hose from your manifold to the refrigerant container with the container in an upright position.Slowly, and in small amounts, introduce refrigerant into the suction line of the system, and allow 5 to 10 minutes for the system to stabilize between addition of refrigerant.

When charging a new system, or recharging an evacuated system, the refrigerant is added by weight, according to the system specifications, but trimming a unit, or adding to an existing refrigerant charge, is less precise. Check pressure and temperature readings, and determine if more refrigerant is needed. Repeat until everything looks normal. Observe a complete cooling cycle. Superheat is heat added to the refrigerant, causing the temperature of the refrigerant to rise above its saturation temperature. To find it, subtract the low pressure gauge temperature reading from suction line temperature. Add coolant to decrease superheat, or remove coolant to increase superheat. Sub-cooling is heat removed from the refrigerant, causing the temperature of the refrigerant to go below its saturation temperature. To find it, subtract the liquid line temperature from the high pressure gauge temperature. To increase sub-cooling, add refrigerant, and to decrease sub-cooling, remove refrigerant.