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It seems ridiculous that refrigerator leaks are not "an uncommon occurrence". Does anyone have any insight into why this would be?

by nl 4y ago

abakker 4y ago
Because flare fittings are a concession to make install cheaper, not better. R410a and other similar refrigerants are very high pressure, and the fittings undergo significant thermal cycles. Flared copper tube is a bad design choice. IMO, going back to brazed tubing connections is the most rational choice.
- lordswork 4y ago
  FWIW, I just had a heat pump installed, and the installer brazed all copper fittings. Are flared fittings often used for these installs?
  - abakker 4y ago
    Most mini splits use flairs, and in the context of heat pumps in the US, I see Minisplits most commonly discussed. The whole house condensers still use brazed connections.
- bluGill 4y ago
  brazed tubes can leak as well. I had that happen in my last house. Little leaks are hard to find, the first time I had the system refilled the tech couldn't find anything and put some sealer in. The next time the tech did the same and was disconnecting the fill lines when he saw a dark spot, then he emptied the lines and did the proper fix.
  - abakker 4y ago
    Sure, anything can leak. Brazed fittings when executed properly and tested are much less likely to _start leaking_. the issue is that the flares have a tendency to work harden during the constant vibration and thermal cycling and eventually give up.
lordswork 4y ago
This is a great question. Data from this website[0] suggests heat pumps leak at 6%/year vs. traditional condensing units which leak on average at 10%/year, so it seems they are still an improvement over traditional ACs. One technician's experience[1] points to the steel accumulator rusting being the primary cause of heat pump leakage. There was a big 2014 study in the UK[2] on heat pump leakage, but no causes were identified, due to poor data collection. [0] https://support.accuvio.com/support/solutions/articles/4000040366-annual-leakage-rate-for-the-refrigeration-air-con-hvac- https://support.accuvio.com/support/solutions/articles/40000... [1] https://highperformancehvac.com/heat-pump-leaking-refrigerant-question/ https://highperformancehvac.com/heat-pump-leaking-refrigeran... [2] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/303689/Eunomia_-_DECC_Refrigerants_in_Heat_Pumps_Final_Report.pdf https://assets.publishing.service.gov.uk/government/uploads/...
bluGill 4y ago
If you have a badly soldered (brazed, welded, or other way to join pipes) joint it will still hold pressure for a month or two. Then mechanical vibration will slowly degrade the joint and eventually metallic fatigue will cause a small break and then you get a leak. Note that most of these leaks are caused by installation. In the factory they have things they can do for quality control to make such things not an issue, but the refrigerant needs to get from inside each house to the outside and that means custom install which makes quality control harder. Worse, it is hard to find leaks. Often the pipes are buried in walls and so all the tech can do is put some sealer in and hope that fixes the issue. There is the ability to put some leak detector in the lines, but then you need to spend a lot of labor and still not guarantee. I don't know what can be done about it, but I know it is a real problem.
c4mpute 4y ago
Leaks are common with quick-install couplings and shoddy soldering. They seem to be more prevalent in the US, because qualification requirements for the installation of A/C and heatpumps are low to nonexistent, and anyone can just visit the DIY store and get refrigerant refills. So a leak isn't much of a problem beyond getting a cheap refill for most people, so craftsmen don't prioritize leakproofness.

It seems ridiculous that refrigerator leaks are not "an uncommon occurrence". Does anyone have any insight into why this would be?

by nl 4y ago

It seems ridiculous that refrigerator leaks are not "an uncommon occurrence". Does anyone have any insight into why this would be?

abakker 4y ago

Because flare fittings are a concession to make install cheaper, not better. R410a and other similar refrigerants are very high pressure, and the fittings undergo significant thermal cycles. Flared copper tube is a bad design choice. IMO, going back to brazed tubing connections is the most rational choice.

lordswork 4y ago
FWIW, I just had a heat pump installed, and the installer brazed all copper fittings. Are flared fittings often used for these installs?
- abakker 4y ago
  Most mini splits use flairs, and in the context of heat pumps in the US, I see Minisplits most commonly discussed. The whole house condensers still use brazed connections.
bluGill 4y ago
brazed tubes can leak as well. I had that happen in my last house. Little leaks are hard to find, the first time I had the system refilled the tech couldn't find anything and put some sealer in. The next time the tech did the same and was disconnecting the fill lines when he saw a dark spot, then he emptied the lines and did the proper fix.
- abakker 4y ago
  Sure, anything can leak. Brazed fittings when executed properly and tested are much less likely to _start leaking_. the issue is that the flares have a tendency to work harden during the constant vibration and thermal cycling and eventually give up.

lordswork 4y ago

This is a great question. Data from this website[0] suggests heat pumps leak at 6%/year vs. traditional condensing units which leak on average at 10%/year, so it seems they are still an improvement over traditional ACs. One technician's experience[1] points to the steel accumulator rusting being the primary cause of heat pump leakage. There was a big 2014 study in the UK[2] on heat pump leakage, but no causes were identified, due to poor data collection. [0] https://support.accuvio.com/support/solutions/articles/4000040366-annual-leakage-rate-for-the-refrigeration-air-con-hvac- https://support.accuvio.com/support/solutions/articles/40000... [1] https://highperformancehvac.com/heat-pump-leaking-refrigerant-question/ https://highperformancehvac.com/heat-pump-leaking-refrigeran... [2] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/303689/Eunomia_-_DECC_Refrigerants_in_Heat_Pumps_Final_Report.pdf https://assets.publishing.service.gov.uk/government/uploads/...

bluGill 4y ago

If you have a badly soldered (brazed, welded, or other way to join pipes) joint it will still hold pressure for a month or two. Then mechanical vibration will slowly degrade the joint and eventually metallic fatigue will cause a small break and then you get a leak. Note that most of these leaks are caused by installation. In the factory they have things they can do for quality control to make such things not an issue, but the refrigerant needs to get from inside each house to the outside and that means custom install which makes quality control harder. Worse, it is hard to find leaks. Often the pipes are buried in walls and so all the tech can do is put some sealer in and hope that fixes the issue. There is the ability to put some leak detector in the lines, but then you need to spend a lot of labor and still not guarantee. I don't know what can be done about it, but I know it is a real problem.

c4mpute 4y ago

Leaks are common with quick-install couplings and shoddy soldering. They seem to be more prevalent in the US, because qualification requirements for the installation of A/C and heatpumps are low to nonexistent, and anyone can just visit the DIY store and get refrigerant refills. So a leak isn't much of a problem beyond getting a cheap refill for most people, so craftsmen don't prioritize leakproofness.