RZ2 Front Ballast problem

[Onyx]

Having an annoying problem with the front ballast tanks on a RZ2. Have a bunch of riders at different skill levels and the guys that want the most ballast tend to go first up. First fill of the day or first fill after the boat's been out of the water the tanks fills no problem at all. Any time we want to fill the ballast again after operating with half or no ballast it seems to get an airlock of some sort. The pumps are definitely working as you can hear them running and if we remove the clip on the fitting to the tank and give it some encouragement with sucking on the hose , the water flows and you need to get the fitting on the tank pretty quick to avoid filling the boat,
I thought it was the non return valves, but have replaced both and no difference. (valves mounted near the ballast end of pipe, as it comes from the factory)
Have no problem with the rear tanks at all. Told the dealer and they have checked and cannot find an issue. it could be to do with going along for an rider or 2 with full ballast and then emptying for a couple of riders and then trying to refill,the dealer would not have time to test the ballast for this time frame.
Wondering if anyone has experienced similar issues or whether there is a fix or advise
Thanks

[Ewok]

So your drain pump are not priming when the bags are 1/2 full, or not priming at all to drain? I sometime get an air bubble in my bow ballast bag and I can hear the drain pump working but it doesn't pump anything out. When that happens I just lift one of the seat cushions and push on the bag to add some pressure and help prime the drain pump. It happens very rarely on my boat, I might have to do this once or twice a season at most.

If this is happening regularly I would look at the plumbing of the bow ballast bag or bags. Which level of ballast do you have, basic, surf or pro? If basic or surf you have the same bow sac as I do and I would look at the vent lines to make sure they near the high point of the bag so you don't get air clogging the drain pump. If it's the pro level ballast you have two 400 lb sacs and again, I would look at the vent line locations to make sure they are near the top of the sac. Someone may have plumbed in your drain lines and pump on the vent holes in the sacs, which would make it difficult to prime the drain pumps.

[chpthril]

For bow sac drain pump priming issue, inspect the orientation of the pumps' outlet. The pumps will often times fall over on their side, in relation to the outlet. This puts the outlet at the 3 or 9 position, rather then at the 12 oclock position where it needs to be. When on its side, air gets trapped in the body of the pump, preventing water from entering. When the sacs are less than full, the issue can be compounded due to having less head pressure at the pumps inlet to force air out.

The trick is to get the pumps rotated to the outlet is up, without twisting or kinking a hose, and then getting it to stay. I have found that securing the outlet hose to the forward locker wall with a cable tie hose anchor, will keep the pump in the proper orientation.

If fill pump priming is an issue, again, the pump's outlet is what needs to be looked at. The outlet needs to be the upward most point.

[lee]

When it happens again put the boat into reverse and back up when you turn the pumps on.

[Onyx]

Thanks guys for the replies. Sorry if I didn't make myself real clear, the problem is only with the refilling priming of the front sacs. The sacs are definitely emptying no problem. I have the pro ballast set-up with two tanks and a pump for each.
With regards to the pumps position both are in vertical arrangement mounted above inlets in the hull between the fuel tank and gearbox as is the position from the factory.
I have tried reversing and moving forward slowly no change. Mostly we are stationary when attempting to fill.