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Air Conditioning and Heat Pump Refrigerant Leakage – Things You Should Know

Air Conditioning and Heat Pump Refrigerant Leakage – Things You Should Know

Copper Tube EvaporatorTwo of the most important systems in your home are cooling and heating. Do you know that a refrigerant in both these systems plays an important part in proper cooling and heating? When these two or one of these two systems stop working, the cause may be a refrigerant leak which just won’t produce cool (in case of air conditioning) or warm air (in case of a heat pump).

Accurate Diagnosis

So, how do you know that the real cause of the problem is a refrigerant leak?

There can be different causes (than refrigerant leaks) when your air conditioning or heat pump system loses cooling or heating capacity respectively. For example:

  • If the thermostat is ‘not’ set to “cool”, it simply turns your AC off.
  • If all switches and controls are checked, including service switches, including inside at the air handler, outside by the compressor and circuit breakers and fuses in the electric panel, and if condensate is found spilling in an overflow pan using a sensor switch, it’s enough to shut your AC down.
  • Many controls and switches, manual as well as automatic, can leave a heat pump or AC turned ‘off’.


After ruling out other causes, if you find that refrigerant level has come down to low or zero, don’t just re-charge the system, but find and repair the refrigerant leak.

Although it’s quick and inexpensive to just add a refrigerant to a system, experts at High Performance HVAC Heating and Cooling scorn building a refrigerant gas delivery path. The system inside a heat pump or air conditioner is often totally sealed and must never “use” refrigerant. Refrigerant gases are not an object “consumed” by an HVAC system.

In an emergency situation, a refrigerant can be added. But the proper solution to the problem is to detect and repair the refrigerant leak.

If the Leakage is in an Access Port or Valve

If the leakage is taking place in an access port or a valve, such as the service ports to which a gauge set is connected by an HVAC technician, the valve may be cleaned and salvaged or may have to be replaced.

evaluation of HVAC system

If the Leakage is in the Copper Tubing

If the leakage is taking place in the copper tubing of the air conditioner or heat pump, a repair can be easy. The damaged line is to be re-soldered with a high silver content solder and a high temperature torch.

If a part of the refrigerant line is damaged, it may have to be cut out and replaced. Whether the leak is in the smaller diameter high pressure line or the larger diameter suction line, the repair is about the same.

If the Leakage is in the Evaporator Coil or Condensing Coil

In this case, repair is possible. But first the problem should be diagnosed, whether it’s dirt, frost or icing, blockage or improper sizing.

If the leak is at a single point due to some mechanical damage, the hole can be detected and repaired with silver solder. If it’s in the copper tubing not near a condensing coil or evaporator coil, it can be soldered, then cooling system can be evacuated and recharged. If it’s very near the condensing coil, a solder repair may be challenging since the heat of soldering may de-solder other adjacent connections. A very expert technician can achieve it if he can keep the adjacent surfaces cooled (e.g. by using a wet rag).

Refrigeration comp and coil

If the Leakage is in an Aluminum Part

If the air conditioner leaking refrigerant is in an aluminum part, soldering aluminum can be tricky and may not be practical. Regular devices like a torch for example will just melt the metal. Expert welders use methods like inert gas welding.

If the Leakage is Because of Severe Corrosion

If there is a severe corrosion anywhere in the HAVC system, there are fewer chances of a solder repair. The factor that caused corrosion may have weakened other parts too. Thus the cost of repair may be wasted.

Detection of Leakage with Halogen Gas Leak Detector

Halogen leakage detector can be used to find gas leaks and for complete examination and testing of the full refrigeration piping system, including evaporating and condensing coils.

heat pump

Bubbles in the Liquid Refrigerant Line

Clean dirt, dust, debris or grass clippings off the condensing coil (including outdoor condenser/compressor units for heat pumps and air conditioners as well as the condensing coil on a home freezer or refrigerator).

Since a refrigeration system operates by passing heat from hot refrigeration gas/liquid to the air surrounding the condensing coil, if the condensing coil is loaded with dirt and debris, this can stop complete cooling of the high temperature refrigerant gas again to a liquid state. As a result, you’ll see or hear gas bubbles passing through the refrigerant metering valve. On systems that feature a sight glass, the bubbles can actually be seen passing through the system.

Gas bubbles in the liquid refrigerant can lead to problems like running water, burbling, gurgling or similar sounds heard from the piping system.

However, there may be another source of the bubbling sound which is near the compressor due to the refrigerant oil pooling in that spot. This pooling of oil is not typically a substantial problem provided the pooling of oil doesn’t block the passage of refrigerant in the system. If the HVACR design is good, the refrigerant piping slopes back towards the condenser/compressor unit from the evaporator unit so that refrigerant oil finds its way back to the compressor motor.

Evaporator of a vapor compression refrigeration installation

Recharging After Repair

If you haven’t realized, to solder a repair in an air conditioner or heat pump refrigerant leaks it’s first required to remove the entire refrigerant from the system.

The technician will connect a vacuum pump on the system to take out as much gas, air, moisture and debris as possible. The technician may also probably install a refrigerant filter/drier to eliminate any moisture that leaked in the system, while it was exposed to the atmosphere and maybe she’ll fit other filtration equipment.

Then the technician will recharge the system with a gauge set and charging cylinder or scale.

By knowing these steps in the leakage repair problem, you have a better understanding now of your heating and cooling system leakage problems and that will help you diagnose them and take a correct action.

Air conditioner

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