https://smile.amazon.com/dp/B00A8OVDJ0?tag=amz-mkt-chr-us-20&ascsubtag=1ba00-01000-org00-win70-other-smile-us000-pcomp-feature-scomp-wm-5&ref=aa_scomp&fbclid=IwAR2nV9eakmpnl4IBxy-ey4U5Xl_N7yqrzlrcZ_WulqPKET01Jy3XYUH6A-gI've got a 2012 A20 with 750s in the rear above the hard tanks. My bags, and yours I assume, have 2 top fittings and one bottom. I've solved the issues with the interval style draining. My rear system works like this. I fill from the top. That is, the fill pump attaches to the top of the bag. The bag is then connected at the back of the bag to the tank via the drain pump (linked above, explained below). The front tank fittings are tied together for the tank vent and I have attached the second top bag attachment via a wye to the tank vent line. So both the tank and the bag are vented - no need to burp.
The key is to replace the drain pump, attached to the rear of the tank, with a dual inlet tank body. The outlet on the pump obviously goes to the side of the boat for discharge. The bottom of the pump is screwed onto the tank like the pump being replaced and the drain of the bag is connected via tubing to the drain pump.
This way the drain pump, when turned on, drains both the bag and the tank. No more need to drain the bag into the tank prior to discharge.
An added bonus is that now everything drains best when you are a little bow up. The front pnp bag is already like this, but before the rear bags drained in the front. Now, with the rear bags draining toward the rear everything drains best bow up.
This sounds exactly like what I am running. With it set up like I have and you had,I haven’t done much playing with it, does the top hose just vent? Or is that a fill line. I looked with the boat in the garage and my I understanding is I can turn the bag around and drain out the back with a new pump. So do I need to add a line to fill? Or is that most add a line as a vent so no need to self vent. Thanks for the help. Trying to figure out the process
