REPLACING REFRIGERANT CONTROLS WITHOUT REMOVING CHARGE

[VTP99]

If Manitowoc wants you to replace in-warranty controls this way, let them worry about the trapped air.

For access valves, I just do a little purge after re-rounding.

Good point icemeister. No problem on the purge if you forget to put to core back in.

[yoyohat]

When you braze in access ports on a true or other unit that is full of refrigerant, is there any worry about brazing a part without being able to use nitrogen? Does this cause any problems down the road with "scaling" perhaps clogging a metering device?

[bob_scheel]

When you braze in access ports on a true or other unit that is full of refrigerant, is there any worry about brazing a part without being able to use nitrogen? Does this cause any problems down the road with "scaling" perhaps clogging a metering device?

You can squirt some nitrogen into the fittings before you braze. Even though it is not flowing it will still prevent oxidation. Also the small amount of oxidation created would be blown out by a purge after you opened the pinch. Usually you are talking about less gas than would be in a charging hose. I do question applying heat to the pinch off to dab some braze on it. That would likely produce some acid by breaking down the refrigerant.

[yoyohat]

Thanks for your reply bob_scheel.

[MicahWes]

Wouldn't applying heat to brazing temperature weaken the copper so that in the end the added brazing alloy gets your strength back to where it would have been if you had just left it alone?

[VTP99]

Wouldn't applying heat to brazing temperature weaken the copper so that in the end the added brazing alloy gets your strength back to where it would have been if you had just left it alone?

If I was to fold a 1/4" copper tube and open it back up it would be quit weak at the kink. Pretty much what you get with the pinch-off tool. Now if you just welded the kink I would agree with you. Personally I would weld beyond that point. It would be much stronger and no different then any other weld you make.