BTW, this is what the swivel adapter looks like. It has a precise machined tapered end face that mates with an equally precise machined end face on the nipple which I decided to use rather than the brass nipples I had. These stainless steel fittings are used on hydraulic lines while there are similar brass fittings used on truck air brake systems. In hindsight, brass may have been a better choice for sealing but I soap test the fittings to ensure there is no air loss. Since there is a regular supply of air anyway, a minor leak would just mean the AVC has less air to have to remove.
I had to pull the second HP (contact) tank this week to clean the AVC that was leaking water to the drain causing the pump to cycle every hour. This tank has a shortened AVC to hold more water and less air. It has the option of connecting the pressure switch to the top (air pocket) if/when I need to remove the primary HP tank for cleaning and the swivel fitting makes it easy.
Given that both HP tanks serve as contact tanks for aerated water to precipitate iron, they need thorough annual cleaning. I pressure wash their interior and use muriatic acid on the AVC. Each tank is setup with unions for easy removal and I have straight pipes to put in their stead so that I still have running water for the house and pressure washer.
The primary HP tank is the next to be cleaned and I expect that it will have a lot more iron buildup than the secondary. Following that, I also need to pull the head off of the iron filter as the top basket needs cleaning.
I have an airline fitting just before the iron filter inlet to blow out all the water from iron filter media tank should I need to lift it out of the crawlspace and take it outside for a thorough cleaning. I just close the valve on the HP tank outlet and supply air while in the fast rinse and pack cycle.
For when the line from the HP tank to the iron filter is removed for cleaning, I can feed water to the pressure washer directly from the HP tank through a dedicated hose bib. At any other time, I can feed the pressure washer from any other hose bib which are all connected between the iron filter outlet and the softener inlet.
