I am considering charging with R-410A a 7 yr old Carrier packaged heat pump 3 ton unit now that it is out of warrantee for all parts and labor.
I must say charging an automobile AC in the comfort of a garage, as I have for many years, seems easier and less risky than the home HVAC.
I removed some of the packaged unit side panels, saw the compressor and the evaporator coil. I was looking but not very hard for the low pressure charging nipple and the high pressure nipple, but did not see the red/blue covers that automobiles have.
Is there a sight glass in these systems to look at bubbles?
This unit has been serviced for evaporator coil leaks twice within warrantee and when correctly charged works great.
The cost of R-410A is $155 for 25lbs gauges are $100 or less in the internet, while AC contractors charge for R-410A $35/lbs and higher. This cost is part material and part labor waiting for the freon to charge.