How to Recognize and Charge An Air Conditioner That is Low On Freon

~~~~~~~~~~~~~~~ Danger High Voltage!~~~~~~~~~~~~~~~~~~~~~~

~~~~You must be EPA certified to perform these repairs.~~~~~~~~~

~~~~~~~~~~~~Always wear gloves when handling~~~~~~~~~~~~~~~
~~~~~~~~~~~~~refrigerants to prevent frostbite.~~~~~~~~~~~~~~~~

~~~~~~~~~~~~Always use quick connect fittings.~~~~~~~~~~~~~~~~

High and Low Side Hook Up at Service Ports

High and Low Side Quick Connected

If you have a unit that is not cooling, first verify that the compressor is running. Feel the suction (also called the liquid or low) side line coming from the compressor. If it is not cold to the touch, this would indicate that the system is low on Freon.
To charge the unit, first calibrate your gauges. (To be safer you can pull the disconnect, and discharge the capacitor before hooking up gauges. To check the system pressures and add Freon you will need to turn the system back on.) Verify that the gauges hand valves are in the off position. Next remove the low side cap for the low side Schrader valve and hook up your blue suction line to the port with your quick connect. Next crack the service valve at your gauges to purge any air from the hose line. This is called a “deminimus release” it uses the Freon to push out the air from the line and is necessary to purge the air from the line. Air contains moisture and if it gets into the system it will mix with the refrigerant and turn into an acid. That would cause leaks and all other sorts of madness.

Low Side Deminimus Release

Cracking the Low Side Service Valve

Follow the same procedure for the high side. Hook up the red high side line to the high side port and purge the air from the line by cracking the line at the service valve again using a tiny bit of the refrigerant to push the air out of the line.
Next hook up the yellow service valve line to your can of refrigerant with the service line quick connect. Keep the can right side up with valve on top for vapor charging (except for very specialized applications) thereby avoiding adding liquid to the system to prevent liquid slugging of the compressor and premature compressor death i.e. A.C. heart failure. Open your valve on the can of refrigerant and purge the service line by cracking the yellow lines service valve for a quick second.

Deminimus Release

Deminimus Release

Your gauges (If in good working order and calibrated) will now give you an accurate reading of what is in the system. The outer ring on the gauges show psi( pounds per square inch) and the inner colored rings show the pressures for accordingly colored types of refrigerants. (Each type of refrigerant has a different temperature pressure relationship but I will save getting into that for some other time.) For example, green is for R-22(At present, perhaps the most widely used refrigerant(Soon to be changed according to the Montreal Protocol, (check my articles on Isceon).

Now you are ready to charge the system. Open the blue  side service handle and you will hear the refrigerant being sucked into the system.I f you are charging R-22 what you want is ambient temperature plus thirty degrees on the high side. If the temperature is eighty five degrees outside then you will be looking for one hundred fifteen on the green r22 high side dial. Each system is a little different so this is only a very general example.

One method of verifying proper pressures is checking the temperature at the evaporator. The ideal temperature for the evaporator for most refrigerants is forty degrees. Another method is to check the temperatures with thermometers for a fifteen to twenty degree split between the air going into the intake vent and the air coming out of a distribution register.

Each system is a little different. This is only a very general guide, with a few methods for checking for appropriate refrigerant charge, not so much hard and fast rules. You must digest the information mixed with the ingredients of your particular setups, area requirements, and always follow manufacturer specs.

~~~ Keep it Real ~ Nice and Chilly ~~~

~~~~~~~Kung Fu Maintenance ~~

~~~~~~~~~~ P.S. ~ Stay Cool ~

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