Dual pump surf bag with check valves setup-- not priming question

[kaneboats]

I sent this question to Moombadaze just now and then thought I'd post it up here because it might help somebody else if we find a solution. Moombadaze did roughly the same mod a while back I did this season so he's been there done that for most of the troubleshooting.

Anyway, here's exactly what I asked him:

I put my extra rule 2000 from one side of the inlet T going to the surf bag. I put a new Tsunami 1200 on the other side of the T going to the other inlet on the surf bag.

Each side has a check valve inline after the pump so water can't drain back down through the pump and out when the bag is filled. Last two times out only one of them is filling. It seems like one of them will prime and the other one will not. There's no way to get water to it from the top b/c the check valve won't let it through. So, if there's an air bubble in there I'd have to loosen a clamp or something to let it out.

Did you ever have trouble with the pumps priming with a dual pump, dual check valve set up? Do you think I need "vented loops" with the duck bill vents or something to let air out?

[jmvotto]

My dual pumps on the OBV did not have a problem priming, but i did not have check valves on there either. went straight to each end of the sprinkler manifold.

[kaneboats]

I don't use a manifold or sprinkler valves on the new thru hull for the side that supplies the surf bag. It's just a thru hull fitting, a T, two shut offs, then two pumps and two check valves. One side fills fine and the other one doesn't seem to prime. After talking with Daze I think the Rule pump on the front end of the setup might just be too high. It's not getting the water it needs when the boat is dunked.

[mnpracing]

I don't use a manifold or sprinkler valves on the new thru hull for the side that supplies the surf bag. It's just a thru hull fitting, a T, two shut offs, then two pumps and two check valves. One side fills fine and the other one doesn't seem to prime. After talking with Daze I think the Rule pump on the front end of the setup might just be too high. It's not getting the water it needs when the boat is dunked.

Where do you have the thru hull drilled? If you have the T on the thu-hull, it seems that's the lowest config you could have, vs Thru-hull, to shut off, to T.

[bergermaister]

I have a thru hull -to- ball valve -to- T setup and both my pumps have no problem priming. Got any junk stuck in the one pump or in the line?

However running them both at the same time cuts the flow down in each by 1/3 to 1/2 I'd guess - just starving them a bit. All 1" lines.

[MLA]

What kind of check-valve are you using? Some require a bit pressure to open, thus trapping air in the pump. Do you have a pic of the pump and t-hull setup? Is the outlet on the pump in question, on the high side of the pump? Its crucial to maintain an upward travel so the water can fill the pump and push out any air. If the pump is oriented so the outlet is off to the side, it may trap air. Also, if the pump body is level or lower then the inlet, it might trap air.

[kaneboats]

The one on its side primes fine. The vertical one is the one that doesn't.

[jmvotto]

The one on its side primes fine. The vertical one is the one that doesn't.

can you post a few pics, that vertical position may be the problem. my rules were both horizontal and no issues priming but i had a scooper and sprinkler valves

[kaneboats]

Not gonna happen anytime soon. I'm temporarily storing my baby outside so it's got the snap covers on and tarps bungeed over that. She's about water tight. Every sunny day I open up a vent at each end and turn on the fans to let her breathe. Probably won't have her out for the next 8-9 days.

[brain_rinse]

I have the 2 pump/tee and check valve setup. The only time I seem to have issue is at the beginning of the season when all of the lines are bone dry. I never had good luck with vented loops so if your ballast isn't auto filling I'd probably stay away. Are your check valves pretty easy to open? The new ones from wakemakers open with no pressure at all but still seal tight. You could try one of those out and see if your situation improves.

If you shutoff the valve, stopping water from flowing to the pump that is working, does the other pump start working OK?

[kaneboats]

If you shutoff the valve, stopping water from flowing to the pump that is working, does the other pump start working OK?

That's a great idea. The extra pressure might just make it work. I'll try shutting the valve on that pump for a minute next time out to see if the first one primes. Might also look for a way to get the pump a little lower

[MLA]

The one on its side primes fine. The vertical one is the one that doesn't.

Do you have enough room to put it on a 90* or 120* elbow to get it down a little? Sounds like thats all it needs.

[newty]

Maybe a backwards or fouled check? Thats the only thing I can think of.

[kaneboats]

Nothing plumbed backwards. It worked before.

[kaneboats]

I didn't get to mess with the setup before we headed out the other day. I tried shutting off the valve to the side that works and only leaving the valve open to the vertical Rule pump side. No dice. It never primed. I filled the surf bag with just the Tsunami 1200 side. I could feel the Rule pump running but it just wasn't pushing anything through the check valve. I'll probably take the whole thing apart and start over. Might add an air bleed screw if I have to.