[Junior1983]

Hey guys i just purchased a bluvac micron gauge and also setup my vacuum pump with a yellow jacket tree for two 3/8" hoses. Im also going to use the core removal tools. Im going to be evacuating a dry charge r22 condenser 3 ton split system heat pump. There is no refrigerant in the condenser. My question is when im evacuating the lineset do i leave my service valves in the condenser open so i can also pull a vacuum in the condenser and lineset at the same time? I just want to make sure its safe and wont mess with the compressor oil. Also if i reach my 500 microns goal and everything holds steady. Do I close my core removal tool with the ball valve and install the schraders? Or do i weigh in my charge without introducing any air into the system? Sorry for the dumb question i just want to make sure im doing my evacuation the right way since im in the process of learning the trade. If you guys can give me any ideas in the way you evacuate your systems will be helpful. Thanks guys.

Better to learn from the pros so i can do it the right way.

 

[Gunslinger]

You will want to let the N2 out of the condensing unit and pull avcuum on the entire system. After you have the proper vacuum and it holds, close off the ball valves, introduce your refrigerant up to the ball valves, purge the hoses, and put refrigerant into the system.

What I do as my vacuum tree has 2 ball valves in it, is to balnk off both valves, open the access cap between them, and then allow refrigerant to enter the system, hen I have abot 20psi, I close off the ball valves on the core tools, remove the evacuation hoses,and install my guages. I do not install valve cores until I am done charging most times. My micron guage also has a core tool on it to protect it. If it is a large charge, when I have 20 to 30PSI in the system, I will stop and install the schraders incase there is a chance of the charge getting lost.

 

[taylor2]

Yes, and yes.
no, and yes.
be sure the hoses and core removers you are using are vacuum rated or else you'll never hold a 500 micron vacuum with the charging hoses in-line. "Charging" hoses are for charging and checking charge, vacuum hoses are for vacuuming. R22 is more forgiving than R410A but that is mostly based on the fact that old 22 systems used mineral oil. Most, if not all now, dry ships are coming with POE oil which does not handle moisture as well. So be sure to purge with nitrogen while brazing and it wouldn't hurt to purge the lines and evap coil with nitrogen before even hooking up the new outdoor unit. Triple evacuate if necessary to reach your deep vacuum.

Maybe I'm a little over zealous with my vacuum methods but I figure a little extra time now saves a lot of time later. I sleep better knowing I did it at our above manufacturer specs. Good luck.

 

[jtrammel]

This is how I do it. Pull vac to 350ish microns (triple evac with nitro if necessary), close ball valves on crts, let stand for 10 minutes, if it doesn't rise above 500 it's good. Take vac hoses off vcrts, put charging hoses on vcrts, purge both hoses to vcrts with refer, open LL vcrt ball valve and charge with liquid, remove bluevac, close high side manifold, turn system on, open low side vcrt ball valve, wait 15 minutes for system to stabilize, check SH/SC, trim charge, close vcrt ball valves, remove hoses, install valve stems, remove vcrts and move on to the next one.

 

[Junior1983]

Thanks for all the great tips guys.:cheers:

 

[mrkelly]

Most do not realize the ball valve cut off's are NOT Vacuum rated,especially when Closed.
About drove me nut's on a 250 micron hold once till I was "enlightened".
Might want to check your gauge set too before hand.My old R-22 set finally gave it up last week due to stem seal leakage and no rebuilds avail anymore.

 

[captaincompressor]

i use the yellow jacket evac system 2. 6cfm bullet pump. use fresh oil every job. nylog on all your connections. core removers. never use manifold gauges for vacuum.

i pulled a line set and evaporator down to 72 microns today!
charge liquid to the liquid side first.
then start system and verify proper superheat and or subcool if it has a txv.

 

[jtrammel]

Most do not realize the ball valve cut off's are NOT Vacuum rated,especially when Closed.
About drove me nut's on a 250 micron hold once till I was "enlightened".
Might want to check your gauge set too before hand.My old R-22 set finally gave it up last week due to stem seal leakage and no rebuilds avail anymore.

Appion vcrt ball valves are vacuum rated, that's what I use. I don't use a manifold for vac.

 

[doug1111]

Yes fill liquid into high side (unit off) weight it in. Take your time. Let system stabilize before you start it up. All this after you vac the complete system. Let run 20 min, adjust SH & SC-- EZ you can do this!!!! Let us know how things come out T/D etc etc. GOOD LUCK!!!