Worker-Become serviceman

[bozicaleksandar]

Hello,Aleksandar again.First I want to thank Brian_UK because help me a lot.Brian_UK if you have that I might
help you please ask!
Because I am so boring,please exuce me.
I have another question.
Please tell me is there anyway to charge unit with refrigerant R410a without using a weight scale(calculating subcooling and superheat with thermometer and pressure readings in order to know how much refrigerant(R410a)add into system ?
Of course if I have some refrigerant in unite in order to
add some refrigerant,because the unite is not fully empty?
Same question with R407c?

Thank you very much!

P.S.
I know that Brian_UK answer that questions and I give
my thanks in advance.

THANK YOU AGAIN BRIAN_UK.

[nike123]

You already have Jim Wheeler charging charts and descriptions about how to charge refrigerant.
Just convert saturation pressures for R22 in temperatures and then that temperature back to saturation pressures for state of any refrigerant of your choice and you have your chart for refrigerant of your choice.

[nike123]

Same question with R407c?

R407 you could top up only for about 10% of original charge, or else you could end up with to much changed composition of gases because of temperature glide.
Safer practice is recovery and recharge with new gas for both refrigerants (r407 and R410) because they are azeotropes (r407 is azeotrope and r410 is near-zeotrope).

http://en.wikipedia.org/wiki/Azeotrope