Just had one of these installed. 50 gallons. Every day I throw an A006 error after three people have showered. You are right, the manual doesn't really explain much. Your video (and the previous one) has definitely shed some light on the situation. I am almost positive that the issue is due to restriction on the outflow given the information provided. Time to start figuring out how to get a larger rigid duct going. I'd also agree that it would be great if they would expose the actual temperature values used to determine "available hot water". Seems odd to me to hide that info. Their algorithm only seems to have 0, 10, 40 and 100 as values. Knowing the upper and lower temperatures would be nice.
I hope it works out for you. The simplest test would be to pull the exhaust ducting off and see if 006 comes back. Would you will to share a video of your duct run? I just did a search for Rheem ProTerra hybrid 80 gal manual. The website manualshelf.com brings up our manual and then page 13 and 14 go over the restrictions of the ducting and how to add them together. I have to assume your installers did not calculate accurately.
