[berniebenz]

Thanks for your interest, Rich.
In summary of my past posts on this subject (advanced search my handle in this thread for details) I was unable to insert the A7’s Cu tubing evaporator snake into my oddball HWH so am moving to add an external HX evaporator into an existing HW recirc loop used for my in floor heating.

Going DIY on the cheap, I lucked out with this $20. SS brazed plate HX from eBay, in that it has been adapted to ¼” flare on one side and ¾” Cu tube fittings on the other without having to machine adaptors. FYI, a ¼” flare to ⅛”FPT brass adaptor is a nice push fit into the ID of the HX’s SS tube and a Cu ½” x ¾” union is a nice push fit over the OD of the HX’s SS tube, adapting to the ¾” recirc loop. Just right for silver brazing. BTDT

Next step is to instal this HX into the HWH’s recirc loop. My concern is the ref side not pooling compressor oil, so I plan to run the evap return line from the bottom of the HX, at the forfeit of counter a flow HX condition. Comments?

How to tap the A7’s ref system? It only has a hi side sealed port, thru which apparently they add their 8.8 oz F22 factory charge. No low side tap.
So, I intend to add an access valve to this hi side tap. The volume of one side of the HX is about ⅝ cup of H2O, likely more than the 30’ of 0.22 OD Cu evap tube?
For the low side, there is a short straight length of ⅜” Cu tube between the condenser coil exit and the filter dryer, sufficient to accept a pierce valve tap for replacement F22.

FYI, the last two A7s on eBay auction that I’ve followed went for $262. and $277. + $60 and $50 shipping respectively. We bought too early!

Suffering from Old Farts’ disease! Planning a project is as always but implementation has slowed down considerably. The only problem with retirement is that one can’t go back to work to rest up! It’s all Go! Go! Go!