# Need some help, school me on R 410a systems please.



## BOTTLEJUNKIE (Sep 12, 2015)

Hello all new guy here and I need some help.
I have been in the multifamily(apartments) industry for 24 years and have only serviced/installed R22 units but have recently been put in a position where I will be servicing R 410a units. The problem is I don't know much about them, I picked up a new SH-35N digital superheat, subcooling pressure and temperature gauge today but having trouble understanding how to use it, this is the gauge I have.
http://www.jbind.com/products/product-search-detail.aspx?SKU=SH-35N

I am so used to just hooking up my old gauges(regular analog) and just reading them like I have for years but this digital/superheat/subcooling stuff has got me scratching my head. Is there a video of the gauge set I have being used anywhere? I have searched youtube but cant find it or can one of you guys explain it to me in layman's terms. any help will be greatly appreciated.


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## airconexpert (Mar 14, 2016)

R410 gas is just another type of refrigerant gas in a newer type of air-con models. It is more environmentally friendly.


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## greenac (Mar 31, 2016)

R410 is CFC free.


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## acservicetech ytube (Apr 8, 2016)

*charging R-410A systems*

OK so I do not have those gauges but if you have a general idea on how to charge r-22 systems then you will know how to charge R-410a systems. The biggest thing is that you need to charge R-410A in with the bottle upside down as a liquid and then you use a vaporizer to change it to vapor as you charge it into the low side. R-410A also runs at roughly 60 percent higher pressure than r-22. You are still looking for that same 18-21 degree temp difference between return and supply duct unless high humidity in the building.

You need to confirm that as long as the outdoor unit is a fixed speed compressor (not a inverter style like a mini split) and if it has a txv in it then you check for subcooling when it is 65 degrees or higher. 

Subcooling is the temp decrease in liquid form and by the way, you can not use a liquid sight glass like on r-22 because of the near azeotropic mixture in R-410A

Check high side gauge convert to saturated temp and minus the actual temp from the saturated temp. If the subcooling is too low then add refrigerant a little at a time to within + to - 3 degrees of the subcooling stated on the rating plate. I like to stay 1 to 2 degrees higher on subcooling for future small servicing losses.

New comfort cooling R-410A units usually utilize a txv for efficiency but you must verify that there is one to know that you could use subcooling for checking charge in ac mode instead of superheat for comfort cooling units with pistons/orifices installed instead. Hope that helps and yes I know this doesn't go over an automatic check with a digital gauge set. I am more responding to your statement in the topic (school me on R-410A)

Also you might want to check out epatest.com as they have a free R-410A online manual for their R-410A certification. It may be a benefit to look into that.


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