What is the name of your state (only U.S. law)? Texas
My AC is 11 months old. The capacitor went out. While the tech was fixing it the line between the outside and inside unit started leaking freon. The tech said it was from a bad solder on a joint. The line was installed with the unit. The AC company told me freon is not covered by their warranty. Their invoice says "1 year warranty on parts/equipment." They also said that it doesn't cover it since I have a home warranty policy. They are going to charge me $429 to put freon in the system since my home warranty only pays $10 a lb. for freon. I feel that I shouldn't have to pay anything.
you have multiple possibilities in resolving this depending information not disclosed.
First, I would love to see how a claimed bad solder joint withstood 11 months of vibration but when the tech was working on the equipment, it suddenly failed/
second, I hope it is being repaired before refrigerant is installed. While that seems like a no brainer, given what you are going through now and you made no mention of it, I just wanted to be sure the repair is made first.
so then what you have to do is read the manufacturers warranty on the unit and any warranty the installer may have provided independently as well. There may very well be a limit on the inclusion of the refrigerant. That is something you need to research before getting all set to fight this either way.
on top of all of that, a bad solder joint on a line is the blamed culprit. Were the lines also supplied by the manufacturer of the unit? If not, the only possible source for warranty coverage would be the supplier of the line and it is very likely they have included a limit on what they cover.
I don't see your home warranty being any sort of issue unless the liable manufacturer's warranty includes such a limit. I wouldn't expect to see such a limitation.
so a bit more:
what was soldered on the line that failed? AC lines are quite simple with the line being a single piece of tubing and either a fitting on the end made to engage a fitting on the AC unit on one end and the evaporator coil on the other or it is nothing more than a piece of tubing the tech solders to the mechanics at each end. If the line was soldered in place (unlikely given today's plug and play world), the bad joint would be the installer's fault. As such, it is not even a part warranty matter but workmanship which allows you to make a claim for the cost of the refrigerant regardless of anything else. It would simply be defective workmanship or in other words; negligence.
if it was a manufactures soldered joint you are back to checking warranties of the supplier of the parts involved and the installers warranty/