404a or R134???

[icehouse]

No matter which alternative Refrigerant you use, you charge 80% of the factory charge. Also these alternatives are near zeotropic mixture so you will have flashing in the sight glass

[sgosine577]

Unit was setup for a semi-hermetic and 404-a, The existing compressor was setup with poly oil. and Hotshot. I installed new filters both suction and liquid, flushed the system with FX11 and purged with nitrogen, Leak tested with nitrogen and R22. Evacuated to 500 microns, and used R404-a, and all is well... Down to 38 degrees.

[smilies]

Originally posted by icehouse
No matter which alternative Refrigerant you use, you charge 80% of the factory charge. Also these alternatives are near zeotropic mixture so you will have flashing in the sight glass

The reason for bubbles in glass is cuz you're actually shortcharging the unit. And actually if you have glass, you have a TXV, which means you have a receiver, which means you should have a solid column. Adjust your TXV clockwise (increase superheat) for the drop-in you are using. Change powerheads, whatever. And before anyone gives me shit, it's worked for years for us with fewer comp failures than others.
With cap tubes you still have to shortcharge it.

[rayr]

Originally posted by jerrycoolsaz

Originally posted by icehouse
No matter which alternative Refrigerant you use, you charge 80% of the factory charge. Also these alternatives are near zeotropic mixture so you will have flashing in the sight glass

The reason for bubbles in glass is cuz you're actually shortcharging the unit. And actually if you have glass, you have a TXV, which means you have a receiver, which means you should have a solid column. Adjust your TXV clockwise (increase superheat) for the drop-in you are using. Change powerheads, whatever. And before anyone gives me shit, it's worked for years for us with fewer comp failures than others.
With cap tubes you still have to shortcharge it.

No one should give u any "shit". In the first place "You can't argue with success". In the second place in the 40 some years i've been in this field I have never found an expansion valve that worked properly without a full column of liquid entering it.

[mdharris55]

System proulby used R-12, check TXV, it should give you an indecation. For R-12 I sub R-409a It will mix with polyester, minural or alkabenzene oil.
Good luck

[tech cr]

Originally posted by rayr

[i]

No one should give u any "shit". In the first place "You can't argue with success". In the second place in the 40 some years i've been in this field I have never found an expansion valve that worked properly without a full column of liquid entering it. [/B]

...........So, I guess when it comes to these new refrigerants we should throw away the old rule book. Yes, there should be a full column of liquid refrigerant going to the txv, atleast with R22,R12,R502 etc. All the original refrigerants.

[frozensolid]

I prescribe to the full column of liquid theory. Think volume, not weight when charging new gases.

[tech cr]

Originally posted by frozensolid
I prescribe to the full column of liquid theory. Think volume, not weight when charging new gases.

...On mt P.T. chart for "hotshot" it says not to clear the glass...go figure......??

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[QUOTE]Originally posted by tech cr

...On mt P.T. chart for "hotshot" it says not to clear the glass...go figure......??

Because Hotshot is sold as drop in. You as a tech should know what is happening when you have 'bubbles' in the glass. What's going to happen if the load increases substantially in the box? What's happening to compressor superheat?