Some folks are worried that the new air conditioners and heat pumps containing flammable gases could be ignited by technicians soldering their system when they are installing or repairing them. We have all heard about horrific building or house fires started by welding sparks and the like.
Available now are push-to-connect and hydraulic press-fit tools that do not require an open flame to attach copper piping together. Which is better and safer?
As far as repairs or installations goes, push-to-connect and press-fit connections are, without doubt, fantastically less time consuming than soldering by far. There is no need to lug heavy tools, nitrogen, and soldering tanks to the job location, be it just to the back of the house and/or the roof. That is great, plus the technician does not have to be trained in proper soldering techniques, he just needs two hands to push the lines together or turn on the hydraulic tools while holding it.
So why would you even consider soldering copper together? Quick connect fittings have been used since the 1950’s for connecting refrigerant lines especially on mobile home ac installations. The problem has been, they start to leak refrigerant after some time, sometimes after a few years, sometimes within months of use.
Why? I believe the “O” rings cannot take the associated vibration of the air conditioner for very long. In fact, when they were most commonly used, if I saw them while walking up to the condenser, I knew that I would almost always have to go get a drum of refrigerant so I could top off the charge if the customer didn’t want to eliminate the quick-connect fittings. Most of the time, they would not since they usually only leaked out two or three pounds and Freon was not considered an environmental hazard plus it was only two dollars a pound.
Fast forward to the present, the push-to-connect guys, and the hydraulic press-fit guys swear that this will no longer happen. I hope that is true, but in more than fifty years of field work, I have yet to see a properly soldered joint leak due to vibration on a residential system.
Our company will continue to solder all joints even though we will get an occasional burn (ouch) for doing so. At least, we can assure our customers that we will always strive to do our best for them and not cut corners just to save them a few bucks immediately but ending up costing them more in the future.
Back to the flammable gas part, there is no danger from soldering with a torch if proper procedures are employed such as system purging and soldering a system only if filled with inert nitrogen. Inexperience in servicing any type of system can be hazardous to you and your property.
I hate to bring the subject up, but the reason for the space shuttle Challenger disaster in 1986 in which seven astronauts were killed was because of “O” ring failure. A pressurized refrigerant system containing a flammable gas sealed with “O” rings sounds like another disaster waiting to happen.