Photograph of client using tissue to look for air conditioning air flow Basic Approach to Solving
A/C or Heat Pump Refrigerant Problems
Fix an A/C or Heat Pump refrigerant problems: leaks, wrong charge, overcharging, undercharged

  • REFRIGERANT PROBLEMS - CONTENTS: Basic HVACR refrigerant problem diagnosis & repair procedures. HVAC equipment does not "consume" refrigerant. You should not normally have to add or replace refrigerant gas. If the charge is too low or high surprising things happen and costly damage an ensue.
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Air conditioner or heat pump refrigerant problem diagnosis & repair procedures: here we explain what happens if the refrigerant charge in an A/C or heat pump system is leaking, under-charged, over-charged, or if the technician used the wrong type of refrigerant. Understanding what's wrong with the refrigerant in the system can explain temperatures that are too low, too high, or it may explain refrigerant line and cooling / evaporator coil icing - too-cold, too-warm or too-weak air flow in the system.

This article forms part of our series on how to diagnose an air conditioner or heat pump that is not cooling: this article explains how to diagnose and correct air conditioning problems like lost or reduced air conditioner cooling capacity, reduced or no cool air flow, reduced or no actual lowering of the air temperature, or an air conditioner that won't start

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Air Conditioner Refrigerant Problems - Refrigerant Leaks, Low Refrigerant, Wrong Temperatures

Air conditioning refrigerant gauge set (C) Daniel Friedman

Refrigerant problems: Improper air conditioner refrigerant charge - too little, too much, too leaky: an air conditioner system which has lost some (but not most) of its refrigerant will sometimes run too cold at the evaporator coil, leading to coil icing and loss of cool air delivery in the home.

If the filters are clean and the coil ices-up this condition may be present. A service technician will need to evaluate and test the system and if needed, adjust the refrigerant charge.

  • Low refrigerant level in the air conditioning system: Watch out for refrigerant leaks that lead to a repeat of this problem. An air conditioner or refrigerator is a sealed system that should not normally "use up" refrigerant.

    If the cooling system is low on refrigerant because it has a leak, it is much smarter to find and fix the leak than to simply keep adding refrigerant. If you keep adding refrigerant to a cooling system you're leaking possible contaminants into the environment as well as wasting money.

    Abnormally low output air temperature: A refrigerant leak in an air conditioning system may show up first as abnormally low system output air temperature, followed by rising air temperatures, followed by just plain old warm air coming out of the system, as the amount of refrigerant that has been lost increases.

  • Loss of most refrigerant from an air conditioning system means that the cooling coil will not get cool at all.

    Abnormally high output air temperature: A service technician will need to evaluate and test the system and if needed, find and fix the refrigerant leak, evacuate the system, and install the proper refrigerant charge.

    Don't keep adding refrigerant. Refrigerant leaks should be found and repaired. It may be easier to keep adding refrigerant, and sometimes a refrigerant leak can be hard to find, and of course it's convenient and profitable for the HVAC repair company to keep delivering refrigerant,

    but the proper repair for low refrigerant is to find an fix the refrigerant leak, not to just keep adding refrigerant.


  • Improper refrigerant charge - overcharging: too much refrigerant can also lead to improper air conditioning system operation and in some cases can damage the compressor (called liquid-slugging the air conditioner compressor).

    A service technician will need to evaluate and test the system and if needed, adjust the refrigerant charge. In this case the cooling coil is probably not going to ice-over, it just won't get cool.



See these additional refrigerant diagnostic & repair detail articles

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