View Full Version : Silver soldering question.

01-12-2001, 05:36 AM
Aloha, do you silver solder the fittings on air conditioners and refrigerators? If the answer is yes, what are the procedures for soldering. I am curious because the compressor has oil in it and the lines must have some oil in it so isn't that dangerous? TIA


01-12-2001, 09:10 AM
Aloha Doug,

I might be right in saying that in refrigeration - air con we do not solder. We either braze or weld using very high temp flames , usually oxy acetelene, which can typically reach temps of 1200 degrees Celcius.

01-12-2001, 09:21 AM
Aloha, thanks for the reply but I know how to weld using oxy/acet but I saw a refrig. tech using the torch on the lines and the compressor has oil in it and I would assume the lines has some too so how does he do it? TIA


01-12-2001, 06:54 PM

Aloha , The compressor has oil in it, yes. the lines..........no they dont. The oil normally drains into the compressor sump. Oil does migrate with the refrigerant, some gasses, like the old R12 are miscible with oil, ie: they carry oil with the gas quite comfortably. So probably during these migrations it is inevitable some traces of oil are left coating the tube walls.

02-12-2001, 10:57 AM
Aloha Aiyub, thanks for the reply and I understand about an open system without gas but what if you had a refrigerator and one of the lines had a small hole in it and you had to weld it closed so all of the gas leaked out but there is still residual oil on the walls of the tubing so can you just weld it to repair or do you have to add a valve to vent whatever gas that is generated by
by the heat of the torch. TIA


02-12-2001, 10:19 PM


Ok, you have a small hole. this is what you do.
Domestic refrigerators usually have an access port on the compressor for charging gas, reading pressures evacuating etc

If you look at a compressor there are usually three ports. Two of the same size and located on the same level but on the opposite sides to each other. On one you will find a short piece of pipe that may have a valve on it or it may be welded shut.

The third is a smaller diameter pipe. This is the high side. Ignore this one.

OEM;s stick a short copper tube stub in and weld it shut instead of fitting a proper schraeder type access valve. ( To save on costs)

You remove this stub, located on the compressor and install a schraeder valve. You obtain these from your wholesaler.
Remove the core from the schraeder valve.

You can also install a Watsco type in line access valve which saves you having to weld a schraeder valve.


Any heat which builds up during the welding process will now be able to escape via the opening in the schraeder valve

Weld the hole.

Replace the core in the schraeder valve, and tighten it

Evacuate system and regas.

Dont worry about oil in the system. Any residual oil clinging to copper tube walls is of insignificant quantity to worry about. Im referring here to domestic and small commercial systems.

I have done hundreds with no problems with oil.



03-12-2001, 05:50 AM
Aloha Aiyub, got it and thanks for the information.


19-04-2002, 05:47 AM
I can't seem to find this item you mentioned:

"You can also install a Watsco type in line access valve which saves you having to weld a schraeder valve. "

What is it? What does it do? How does it work? Where can I get some? How much do they cost?

Please email me with the information.

19-04-2002, 05:55 AM
Would you be referring to a 'clamp-on' access valve?

If so, how do you get around the EPA requirement of returning the hermetically sealed system back to being hermetically sealed?

19-04-2002, 11:56 PM
I'm pretty certain that when they refer to a hermetic system, they mean, a leak free system. If installed correctly, those piercing valves can be expected to stay leak free for weeks on end, thus rendering the system "hermetically sealed.:rolleyes:

ie. I don't think the addition of a permanent access fitting causes an EPA violation...

20-04-2002, 12:23 AM
Originally posted by condenseddave
those piercing valves can be expected to stay leak free for weeks on end, thus rendering the system "hermetically sealed


20-04-2002, 05:15 AM
When I last checked, the description of a hermetically sealed system was a system without a permanent service aperture, thus meaning when you finish the repairs, the aperature would be removed and the process stub welded (brazed) shut.

I reseal all of mine because when dealing with the epa (government), you are guilty until proven innocent (and sometimes then too), and the extra 3 minutes it takes to reseal a system is well worth the time investment. If it's sealed, they can't complain or fine you.

Last time I checked, fines ranged from $10,500 to $27,500 (US)

If I can find the reference to the law, I'll post the url for you.

27-04-2002, 04:50 AM
on larger systems purge with nitrogen, an inert gas, won't support combustion... um, the watsco is a clamp on... Oh! Use an extended tube...