Heat Pump Leaking Refrigerant QuestionHeat Pump Leaking Refrigerant Question - I get this question a lot from both my customers and my site visitors. They tell me every year a technician comes out and pump a few pounds of refrigerant into their unit and its good again for another year. A refrigerant leak for an air source heat pump is not uncommon. Or is it? Let us explore the question a bit further and see what really happens when you refill the unit over and over again, year after year.

Heat Pump Leaking Refrigerant Question

For a heat pump it can mean it is costing you a ton of money in the winter time because your system will run off the back-up heat most of the time. Back-up heat is more expensive than running the condenser to provide heat provided the temperature outside is not extremely cold. The colder it gets outside the less efficient a hump pump is at providing heat for your home. If you have electric backup heat the cost is exorbitant. If you have a dual fuel heat pump system then you have a gas furnace for backup heating and the efficiency of that depends on the AFUE or efficiency rating. The AFUE rating only applies to the efficiency of the gas furnace and not the heat pump.

Either way, its more expensive to heat with the backup heat than it is for the condenser to provide the heat for most of the heating season…………again as long as the temperature is not too cold ~35°F. This does not apply to geothermal heat pumps. All the geothermal heat pumps I worked on or serviced did not have backup heat. I am not aware of any geothermal heat pump system that has backup heat. There may be some out there but not to my knowledge.

The Cycle | Heat Pump Leaking Refrigerant Question

Most of the time the homeowner will recognize a problem with their heat pump in the Spring. This is the time when they turn it to the cooling mode. It is then they see the heat pump is not cooling as it should. This also means they were running it in heating mode with only the backup heat providing heat. They did not know there was a problem because the heat was coming from the alternate source. This alternate source, the backup heat, was costing them more money. So this cycle goes on year after year until the heat pump suffers a catastrophic failure or refrigerant leak. Then it is time to either repair or replace.

Where’s the Leak? Replace or Repair? | Heat Pump Leaking Refrigerant Question

A vast majority of the refrigerant leaks I’ve repaired happened to be the accumulator was rusted out.  However, a refrigerant leak can be anywhere in the system from a leaking shraeder core to an evaporator coil to any other refrigeration component in the system. The problem with accumulator is they are made out of steal and are installed in the condenser. Accumulators are subject to all weather conditions and eventually rust out and start leaking refrigerant.  Its not a cheap repair but its not very expensive either. All the refrigerant needs to be recovered and then the old accumulator cut out and new one piped in. Fixing a refrigerant leak requires a HVAC technician knowledgeable in refrigeration and proper practices.

If the heat pump is very old, say over 12 years old then I would consider replacing for two reasons. First is the cost of the repair versus what you could put into a new system that will be far more efficient. Any refrigerant leak also means the oil has been leaking out of the system. Most residential systems have hermetically sealed compressors. This makes it nearly impossible to add oil to the system to replace what was lost. Eventually, that loss of oil will take its toll on the mechanical parts of the compressor and they will fail. A compressor is a very expensive repair. This is why serious consideration should be made for replacing rather than repairing. Why spend a lot of money on the old system when it is likely it will fail soon after the repair?

Replacement Considerations | Heat Pump Leaking Refrigerant Question

Heat Pump Refrigerant Leaks

The accumulator is the component bottom right.

If you decide to replace then there are some considerations that need to be addressed. If the system is the old R-22 refrigerant system then the line set needs to be replaced. The old line set can be flushed, however it much better if the line set is replaced. The oil from the old system will not mix with the oil from the new system. The old system (R-22) uses mineral oil while the new R-410A systems use synthetic oil. If the old oil mixes with the new oil it can create a big problem this will cause the new system to fail. This is why I recommend replacing the old line set. That and pipe size will likely be different for the new system. The new system will likely require larger piping over the old.

Next is efficiency level of the new system. Choosing a system that is far more efficient is always better than a system that is not so efficient. For help in choosing the right system and contractor see our HVAC Consumer Buyers Guide.

Repairing the Leak Considerations | Heat Pump Leaking Refrigerant Question

If the leak is found in the accumulator that does not mean you don’t have another leak elsewhere. Or even if the leak is found in another component. The technician should do a high pressure nitrogen leak test before finally declaring the system leak free. Another way to test this is using a micron gauge when they are pulling a vacuum on the system. A vacuum is necessary on all refrigeration systems to remove air and other impurities from the refrigeration system. This is done before the heat pump is recharged with new refrigerant. i use both methods before recharging any refrigeration system. It is a part of the triple evacuation process that should be done before any refrigerant is reintroduced into the refrigeration system. It is a part being very thorough and the results are very good if done properly.

Conclusion | Heat Pump Leaking Refrigerant Question

Finally, we hope this helps answer your questions about heat pump refrigerant leaks. Hopefully it enlightened you to a small problem before it becomes a big problem. Happy heating and cooling!

High Performance HVAC Heating Cooling

Heat Pump Leaking Refrigerant Question

 

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