House AC Unit Still Sealed?

Originally Posted by AdmiralAluminum

Is there anyway a household AC unit could still be filled with refrigerant if its at the curb? Copper piping is just clean cut, not bent or sealed off and there was a triangular piece of radiator on top of the unit unattached to anything. Is there a way to tell (besides the obvious and illegal breaking of the lines) if a sealed unit is still "sealed"? No one was home, it was garbage night and I really didn't want to just leave it there knowing what I could get out of it.

There is no freon in it if the copper has been cut. If you picked it up as the guy cut the copper, it would be gasified in minutes.

Originally Posted by AdmiralAluminum

Thanks for the quick reply. I'm not sure I understand "gasified" but I think you mean evacuated? Any way, I hope it was done properly and look forward to taking it apart and cashing in on someone's laziness.

An AC works by compressing the freon gas into a liquid. As it does, There is a tremendous amount of heat that is added to the freon as a result of the compression. The liquified freon is cooled in the condenser coil and the cooled liquified freon is moved to the evaporator coil where the liquified freon is allowed to return to a gaseous state. When it does, it is sucking up energy that is required to cause the liquid to gassify. An AC contains far more freon in the form of a liquid than it does as a gas. When the sealed freon loop is breached, the liquid freon returns to its' gaseous state, because it is no longer held under sufficient pressure to maintain a liquid state.

It most likely was not done "properly".

Originally Posted by KzScrapper

Sorry dude but you are wrong...Using a recovery machine you can suck all of the freon back into the A/C unit and close the valve. The line can be cut and if the unit is still good it can be transported with the charge still inside and used elsewhere. You would also do this if you are changing out a leaking coil in the furnace...once the coil is changed you can let the gas loose again.

The only way to tell if a unit is charged safely is to hook up some gauges IMHO.

Interesting. While I did misread his post and thought he was talking about a wall unit AC, I was not aware that the freon could remain in the unit once the copper line had been cut. I guess if the valve isolated the freon, it would remain with the unit.. I find it unlikely that a compressor coil was thrown to the curb with its' freon still in it, though.... Relatively few people get rid of an AC compressor because it was working too well.

KZ I wanna say one thing-the ac unit in a split system application can be used as a recovery system. A split system is a air handler/furnace with a coil. Hooked to the indoor coil by copper(aka line sets) the copper is hooked to a outdoor condenser. Within the last 20 some years most condensers have valves on them. (Usually)The liquid line(smaller of the two with no insulation usually)can be shut then unit ran. I use a screwdriver to hold the contacts in and run the compressor,while watching my gage.when gage gets close to zero then the suction line can be closed. The freon has been captured BUT unit will only hold up to a certain amount. Most units are shipped with enough juice for a lineset for15-25'. Notice I said juice,since freon is being phased out unit can no longer be shipped with freon in them. So now in a r-22 unit they use dry nitrogen. 410a units can be shipped "pre charged" with a measured amount of 410a. 410a is the new refrigerant replacing r-22.

Originally Posted by KzScrapper

Sorry dude but you are wrong...Using a recovery machine you can suck all of the freon back into the A/C unit and close the valve. The line set can be cut and if the unit is still good it can be transported with the charge still inside and used elsewhere. You would also do this if you are changing out a leaking coil in the furnace...once the coil is changed you can let the gas loose again.

The only way to tell if a unit is charged safely is to hook up some gauges IMHO.

Agree 100%.

I'd like to add that many split A/C systems and commercial refrigeration systems (including smaller movable refrigerators and freezer) have valves where you can isolate various areas of the system. Trust me. I learned the hard way, many years ago when I first got a recovery machine. On these units, you could evacuate certain areas and replace or repair parts without removing all the refrigerant. Anybody playing with refrigeration or A/C equipment should be aware of this. Just because a line is cut, it doesn't mean that the entire system is drained.

One other point that I'd like to make is that most people would not be able to tell if a system was evacuated if it was done properly. Most larger systems have access ports and the unit will look exactly the same when we are done evacuating it. On smaller units, we need to create our own access point. This can be done using a bullet piercing valve. This valve creates a small hole about 1/16" in diameter in the copper line. This valve could be placed almost anywhere on any portion of the line.

All I will say is please know what you are doing! Have someone with the knowledge to show you. All it takes is once and you could be scarred forever!