Table of Contents
- This article will instruct you on the top reasons and places in the HVAC system for refrigerant leaks. Some people say Freon® leaks.
- What happens when an air conditioner or heat pump has a low refrigerant charge as a result of a refrigerant leak. How a refrigerant leak affects your AC system.
- What you will see or experience with your heating and air conditioning HVAC system if you have a refrigerant leak.
- Why HVAC Contractors do not provide warranties for refrigerant leaks for heating and air systems.
- Making the decision to repair the leak or replace the system.
- Basic air conditioning repair and heat pump repair. How repairing a leak will take your system from low efficiency to high efficiency. This can also apply to a mini-split or ductless system.
- Differences between new refrigerants and old refrigerants.
- Plenty of in-depth related links that will allow you to understand the subject better.
HVAC Refrigerant Leaks | Air Conditioner Leaking Freon® - R410A - R22
Top Reasons for AC Freon® Refrigerant Leaks – Air Conditioner Refrigerant Gas Leaks – Air Conditioning Refrigerant Leaks –
HVAC Refrigerant Leaks
There comes a day when the air conditioner stops cooling and you call your local HVAC contractor or air conditioning contractor for air conditioner service and repair. Your air conditioner is blowing hot air. Do you have an Air Conditioner Refrigerant Leak? The HVAC service technician arrives and checks the filter and some other things. You see him go to his truck and get some tools and a set of gauges while you hope for the best. Ten minutes later he comes back to report to you that your air conditioning unit is low on refrigerant.
Now comes the time when you need to understand why the air conditioner needs refrigerant and what to do next? Will this involve repairing a leak or getting a new heating and cooling system? You need air conditioner repair to fix the leak. The HVAC contractor specializes in repairing freon leaks so your AC won’t blow warm air.
Air Conditioners and Heat Pumps | HVAC Refrigerant Leaks
First of all the air conditioner or heat pump (if you have a heat pump) does not consume Freon or refrigerant. The system is a sealed system and the air conditioner does not burn or use up refrigerant to make your house cool. Cool and heat your home if you have a heat pump. Therefore, it should never have to be filled up unless a leak occurs in the system. Heating and air conditioning systems are supposed to be sealed but leaks do happen.
How, Why, and Where? HVAC Refrigerant Leaks
From time to time a leak occurs in the air conditioning system and the unit needs to be charged. A correct and precise charge is important so that it can continue doing its job of cooling the home. As the refrigerant leaks out, the system still cools. It cools too much. The indoor evaporator coil begins to freeze up because the temperature of the evaporator coil drops below the dew point.
That is humidity or moisture in your home or business, which passes through the air conditioning (or heat pump) indoor coil (evaporator) for conditioning. The refrigerant in your air conditioner is supposed to be locked in a hermetic system and sealed tight.
Signs of a Leak in an Air Conditioner or Heat Pump | HVAC Refrigerant Leaks
A leak causes ice to form on the coil and other parts of the air conditioner. Ice buildup on your AC stops it from cooling. The air conditioning system experiences a reduced amount of airflow because of the coil ice buildup. You may notice ice on the copper refrigeration lines, which run to the outside condenser.
If you see this, it is important to shut the system off immediately and call your HVAC service company. If the system is left running, the indoor evaporator coil will turn into a block of ice, and no airflow will come out of the vents. Reduced airflow is a symptom of a refrigerant leak.
Related Link: On a refrigerant temperature-pressure relationship chart or PT chart the less refrigerant in the system the colder the system. When the temperature of the coil drops below freezing, the moisture in the air freezes to the coil. (link opens in a new window)
Your vehicle typically uses R-134A, which is different than what is in-home air conditioners and heat pumps. Technically, it is inaccurate to refer to refrigerant as Freon®. Freon® is a name used to describe R-22 made by Chemours (Dupont spin-off). R-22 is currently being phased out with the final phase-out date set for 2020.
Air Conditioner Leaking Freon® - Causes of Refrigerant Leaks - HVAC Refrigerant Leaks
The most likely leaks for a central air conditioner system can be anywhere and caused by various things. Air conditioning units, as well as heat pumps, are mechanical systems with moving parts. Here are the reasons why your air conditioner has a Freon or refrigerant leak:
- Leaking Shrader Valve
- Heat Pump Accumulator Leak
- Capillary Tube Leak
- Flare Connections
- Evaporator or Condenser Coils
- Filter Dryers
- Line Set
Leaking Shrader Valve | HVAC Refrigerant Leaks
A Shrader valve is leaking Freon and needs to be replaced. There is a tool that can be used to change this Shrader valve without having to recover the entire amount of refrigerant from the system.
These Shrader valves look like the little valves in your car tire. They hold the refrigerant in the system and allow the technician to access the system to test the pressures or to charge the system if necessary. These Shrader valves are necessary, and sometimes the rubber seals deteriorate, or the Shrader valve gets stuck and allows Freon or refrigerant to leak out of the air conditioner system.
Shrader valves are located in or near the condenser unit but can also be in the indoor unit, the air handler. Consider yourself lucky because this problem repaired easily.
Heat Pump Accumulator Leak | HVAC Refrigerant Leaks
If you have a heat pump heat pumps have accumulators. Accumulators are necessary for the heat pump system to provide heat in the winter and protect the compressor from liquid slugging. Accumulators are steel, and after a few years, they begin to rust.
These rust holes allow Freon or refrigerant to leak out of the heat pump system. The heat pump accumulator replacement is possible, but the recovery of the refrigerant is necessary, and a new accumulator installed.
The new accumulators sold on the market today are also made of steel and will eventually leak after rusting occurs in the future. It is hard to say what the average life expectancy of an accumulator is and depends on the quality of steel used to make the accumulator, so the time varies on when the accumulator will leak.
To prevent this from occurring in the future with a new accumulator or new heat pump it is not a bad idea to spray the accumulator with some rust preventing paint upon discovery of a rusty accumulator on an air conditioning preventive maintenance check.
Capillary Tube Leak
A capillary tube is leaking on the inside evaporator coil or if you have a heat pump on the outside heat pump condensing unit. These capillary tubes are tiny copper tubes, and over time and through the vibration of the system, they rub together or rub against another piece of metal.
A hole appears on the capillary tube, and Freon or refrigerant leaks from the air conditioning or heat pump system. These leaks can be difficult to find because disassembly of the system is necessary to find the leaking capillary tube.
Upon discovery of a leak, a cut is made in the capillary tube, the hole for the capillary tube reamed, and another larger piece of copper tubing soldered over the capillary tube.
This does not apply to capillary tubes which connect metering devices to thermostatic expansion valve (TXV) bulbs. These damaged TXVs need to be replaced and do not contribute to leaking Freon from the system.
If the air conditioning or heat pump system has any flare connections, leaks generally occur at these connections. Sometimes these flare connections can easily be repaired while other times the flare fitting and connection have to be replaced and remade completely to prevent future leaks in your AC unit.
Evaporator or Condenser Coils | HVAC Refrigerant Leaks
The indoor or outdoor air conditioning or heat pump coil is leaking and needs repair or replacement. Most of the time, the leaks in the coils (whether they be outside or inside coils for an air conditioning or heat pump system) occur at the u-tubes. These are bends in copper at the end of the coil.
There is a tube sheet made of sheet metal that holds the coils together, and over time, and through vibration, the u-tube part of the coil rubs against the tube sheet, and a refrigerant leak occurs. Sometimes this can be easily repaired, but other times, replacing the coil is necessary. Depending on the age of the unit, indoor and outdoor coils are available for replacement.
The problem with leaks near the tube sheet is when the technician uses heat to repair the leak in the coil, the heat loosens other parts of the coils, and another leak could occur. It will take a very good technician who knows how to braze very well in order to repair this type of refrigerant leak.
Filter dryers are installed in all refrigeration systems. They are necessary for absorbing minute amounts of moisture in the system and for filtering trash before it gets to key components, which could be damaged or plugged if the trash was allowed to get to the components. These filter dryers have screens and desiccant inside them and the steel outer shell.
The same problem that occurs with a heat pump accumulator will eventually occur with a filter dryer, and a refrigerant leak occurs. Replacing the filter dryers is easy but only after recovering the entire amount of refrigerant or pumping the entire amount of refrigerant contained in the air conditioner or heat pump system into the condenser using the pump down method.
The line set which carries refrigerant back and forth from the condenser to the evaporator coil has been pierced or damaged. Damage can occur from a lawnmower or someone tripping over the line set. Additionally, line sets generally run in voids inside walls and ceilings just below the roof.
I once had a line set that was pierced by a nail on a roof repair. The refrigerant took a year to leak out before the air conditioner was no longer functional and the customer required an HVAC professional to troubleshoot and repair the air conditioner system.
Refrigerant Leaks Final Advice - Air Conditioner Leaking Refrigerant
That covers the major types of HVAC refrigerant leaks which occur with air conditioner and heat pump systems.
Depending on the age of the air conditioner or heat pump system and the type of refrigerant leak which occurs may determine whether or not you decide to replace the air conditioner or heat pump system.
Many air conditioning and heating service and repair companies will not provide a warranty for refrigerant leak repairs.
Because it is possible to repair one refrigerant leak and have another refrigerant leak occur in a different location.
It is a decision you must make by weighing the cost of the repairs versus the age of the equipment versus the cost of installing a new coil or air conditioning or heat pump system.
If the unit is old and has caused many problems, the decision may be easy, but it is a big decision, so take time and weigh it carefully.
Related Links | HVAC Refrigerant Leaks
Heat Pump Low on Refrigerant - Heat pumps are not immune to refrigerant leaks. Find out how to tell if your heat pump needs refrigerant.
(links open in a new window)
Refrigerant Leak Advisory | Health and Refrigerant Smell
Additionally, caution advised when around refrigerant chemicals, including the oil in the refrigerant, that lubricates the system. Newer refrigerant oils such as the POE’s or Polyol Ester Oil used in HFC refrigerants will absorb moisture, including the moisture in your skin, causing a burn. Furthermore, if your system is leaking refrigerant, it is almost assured that there is oil near the leak area.
The smell of refrigerant is nearly odorless. There is a slight chemical smell to most refrigerants. If you are a technician, be aware when brazing. When refrigerant burns, it turns green. That is phosgene gas, and it is very severe for your health. Avoid breathing it. The refrigerant in HVAC and automotive systems are asphyxiants. Too much will in a small area will take your oxygen away.
Most homeowners do not have to worry about this problem. If you are a technician and working on larger systems in a small mechanical room, a large volume of refrigerant can overcome you.
Make sure whether you have an older central air conditioning system or even a new air conditioning system, an air conditioning service provider for air conditioning maintenance. Heating and cooling systems, as noted above, are mechanical systems with lots of moving parts. It’s a good idea to have an expert check out your air conditioning equipment to make sure it is running optimally.
They can give your system a tune-up and find any problems that can result in a potential catastrophe in the future. Leak repair will increase your SEER rating, which will decrease your utility bills. Air conditioner repair of a leaky system will also give you better home comfort.
Conclusion | Refrigerant Leaks | Leaking Freon
Additionally, preventive maintenance can spot potential problems. Preventive maintenance can prevent expensive air conditioning repair bills. AC units have lots of moving parts and electrical and mechanical processes and need regular maintenance. AC maintenance can prevent AC freon leaks. It can also reduce your electric bills and keep your central AC running reliably.
HVAC Refrigerant Leaks – Leaking Freon
Technical Resource: Refrigeration and Air Conditioning Technology