That is why when brasing you should be using nitrogen gas to purge the lines. If you do not you could end up withmajor problems.
A numer of years ago I had to repair a lot of lines on a system that had soft sodder used on them. The building was a grocery store that went out of business. A department store purchased the building and was using it as a clearance store. Additional AC was added to the building. Someone came up with the bright idea of using the old condencers for the cold storage units. They were R12. The AC units that were put in were R22. Temperatures and pressures on R22 are higher than R12. On a really hot day the soft soddered joints began to leak and come loose. So al low temperatures soft sodder may be stronger but I would question anyone who would use it on a AC system.
Soft solder melts at temperatures around 350F or higher, iirc.
An R22 system will run maybe 300psi on a very hot day. That corresponds to 130F. (and, in fact, pretty inefficiently at that. Most R22 systems will run 250-300 psi on hot days)
At 350 psi it will be at 145F.
At 500 psi--------which no R22 compressor will run at for more than a couple seconds------it will be at around 210F.
Have you ever seen a R22 with a liquid line temp anywhere near 350F?
I haven’t. I haven’t even seen it in a heat pump where the suction line becomes the discharge line!
I am not going to dig out my PT chatrs but 145 degres at 350 sounds about right for saturated temperature. But the discharge from a compressor is superheated. Last time I shot the heads of a compressor with a rey teck the temp on the compressors with an water cooled tower was in the 190 to 230 degree range.
I would like to note that the OP has a hole in the evaporator, which is on the low side of the system, and while in operation probably will never see the high side of 100PSI.
Ok, so here is an update. My father in law works with an A/C guy - they live in W Mass - about 60 miles from me.
He is going to take a look at it to see if he can fix it. I dont know the guy personally, but as I mentioned in a previous post, apparently this guy knows a thing or two about fixing this kind of thing (according to FIL).
Having him take a look at it required that he be able to have the unit on his bench - which meant removal and disconnection of the A coil from the refrigerant supply and return lines. So last night I disconnected everything, figuring that if he can’t fix it - it’ll need replacement anyway, so no harm done. Today when we were visiting the in laws, I dropped the A coil off, and FIL is going to bring it in to work tomorrow. I"ll have an idea as to the repairability by EOD tomorrow.
If it can be repaired, he’ll do so, and at some point I’ll pick the unit up and put it back in. Then in the spring this guy can come out, braze the supply and return connections, and recharge.
This appeared to be the best option on the table at the moment. Even though I dont know the guy, going on the word of my FIL is better than randomly shooting darts at names in the yellow pages. It might be a little more effort having to remove the unit as opposed to an in place fix, but again - seemed to be the best and most known-quantity option on the table.
If it works out, I can use the coil I already have, and be down the cost of supplies and whatever payment this guy will accept (he recharged my wifes vehicle A/C in the past for a batch of home made cookies - so there is the chance he’ll ask for very little, if anything). If it doesn’t work - then its likely the coil would need replacement anyway.
In my opinion - the original guy saw an ancient furnace, and an A/C unit that uses R-22 which has a bit of an EOL to it (since R22 cannot be obtained after 2020) - and tried to take the opportunity to suggest replacement of the coil at a minimum, and heavily suggesting to replace the entire A/C unit.
I think that personally, because he’s not an independant guy (works for a larger corp), that their mode of operation is to replace with a warrantable unit, rather then patch.
Another update - FIL coworker was able to patch the hole pretty easily. It was put on his desk @ 7:05 in the morning and by 7:45, it was patched, the in/out tubes plugged and the unit filled w/nitrogen to protect it until it can be installed in the spring.
The guy asked ‘what the hell was the other guy thinking, saying that it couldn’t be fixed?’
It it was the discharge line I would always braze. (even though it would still be unlikely to melt, though certainly not impossible) However the discharge is a foot long and only from the compressor and condenser coil.
But he’s got an A/C system and Rick points out that this patch is in the evaporator will likely never ever see even 100 psi---- a P/T relationship much less than 130F.
Still, the patch must be done with brazing. But the system itself, in my view, can be soldered. (and if it’s already brazed, theres nothing wrong with rebrazing.)
He would be better off. Just tappiing up the lines will not keep out moisture. Moisture and most refer oil = acid=a lot of problems. The moisture can be removed in the spring time but is extra work and expense.
I am going to have the same guy who patched it also rebraze the connections and recharge the unit. At this point, I think that going with someone who I know to be capable is the best option.
The only issue is that due to a new baby in his household, he wont be able to make it until around spring. Plus, from what I gather, that is the best time to recharge a unit with refrigerant. This is based on what the original repair guy said, so I take it with a grain of salt. I dont quite understand why it would make that much of a difference - seems to me an experienced person would be able to look at the original charge in the condensor, take into account line length from the condensor and evaporator, and get the proper amount of refrigerant in there.
OTOH, the guy who repaired it originally said himself that someone would have to fill it in the spring. So perhaps there is something going on there that I’m not aware of.
So a long winded way of asking - since its not going to be reconnected until spring - what would be the best option for preserving the two open lines now coming from the condensor? Right now I just have tape to keep some dust, etc out - but moisture can still get in. Is there anything else I should do to maximize protection, short to a full reconnection?
Close off the valves on the condencing unit. There should be a valve on the return line and another valve on the liquid feed line. I would talk to the man that repaired the coil he will have suggestions.
The propere way to lay up the unit would to be to cap the lines, evacuate, and put on a N2 charge. Some what like what was done with the coil.