View Full Version : Check valve for ballast system

03-11-2009, 05:59 PM
I have 4 sacs plumbed in, two sacs in the back both which are hooked to rear tank overflows and 2 side sacs in the front that are hooked to the kgb overflow. are check valves needed to help prime the pumps. I have used them a couple of times iwth good success and this last time i had trouble priming the center tank/sacs to empty. I did vent one of the front sacs into the same rear vent so I could use the same thru hull on the port side, could that cause the issue?

anybody know where to get good 1 way check valves for 1" ballast hose?

03-11-2009, 06:20 PM
here is a quick drawing for reference...let me know what you gusy think. do i need check valves on the vents to help create suction or will it be fine?

Eagle Lake Rebel
03-11-2009, 07:33 PM
West Marine Part # 248138

03-11-2009, 08:14 PM
thanks that is what I was looking for but should i need them? the factory system does not have check valves?

03-11-2009, 09:15 PM
check valves are a good idea, my friend added them to his X-1 rear sacs and it makes the sacs drain completely. I don't have check valves on my X-star's extra rear sacs but maybe they would help me too. I'm not running any extra sac connected to the KGB tank yet, but I will say my KGB loses prime sometimes when emptying. What I do is accelerate just a little to get the nose of the boat up higher and then hit the switch to empty, seems to help. The X-stars sit higher in the stern than the bow, so I think they lose their prime at times.

Another thing to try is empty the KGB first, then the rears. (takes longer this way though)

03-11-2009, 10:06 PM
yea that makes sense. now that I think about it, the time I had problems with the front I had drained the two rear sacs and tanks first making the bow sit even lower and making it harder to prime. the water would have been flowing uphill and wasn't getting to the pump to prime it. hopefully thats the issue

Eagle Lake Rebel
03-11-2009, 10:32 PM
I think the theory behind the check is to help the bag suck down tight. Fly High uses them but the bags are isolated from the hard tanks. I'm about to do the same on my boat and I'm trying the no check way first. If it turns into a problem I'll add the checks.

03-12-2009, 09:38 AM
are you going to use tank overflows or T off the fill/drain for the tanks?

Eagle Lake Rebel
03-12-2009, 11:15 AM
I'm going to let the hard tanks overflow into the bags. If it works it's the simplest and cheapest way to do it. It also saves the step of moving valves into position. I don't see why it won't work but I'm sure something won't go as planned.

03-12-2009, 12:18 PM
thats the way I did it and its pretty straigth forward, let me know if you have any questions.

03-12-2009, 03:53 PM
I am adding the fly high sacs to my X2 and I got check valves from lowes in the plumbing section that look like they will work just fine for $8. I am putting in a tee and a few ball valves at the pump so I can control what sacs I want to fill. I was told it might not be a good idea to run off the overflow because there is a chance that you can put to much pressure on the take and it might crack. The only was to replace the kgb if it cracks is to split the deck and hull apart to get to it, and that sounds like it could cost a few bucks so I am not going to risk it.

03-12-2009, 04:29 PM
the more i think about it the more i think check valves would be a bad idea. if your tank cant breath while draining wouldnt it eventually suck a dent in it and potentially crack it?

I have heard of concerns regarding plumbing in sacs via overflows and that is why its important to make sure you have plenty of room and no kinks in your hose. I used a dremel and cut a half moon shape to get the kgb overflow through to the where the sacs are on each side. I looked under at the tank and it didnt seem to strain it much at all when filling

Holman J.B.F
03-12-2009, 05:36 PM
A check valve on the bags vent will create a vacuum in the hardtanks.

oops...didn,t see page 2

03-12-2009, 06:08 PM
funny thing... on my buddy's SANTE 210 (exact same ballast setup as the new MCs... or at least an xstar and x2) we added bags just like you speak of (directly off the overflow of the hard tanks) and we figured out really quickly that if you don't keep air flowing through the bags that you will create suction a dn dent the tanks in as well... at first we thought the weight of the bags had dented the tanks in and he turned off his pumps and we watched the tanks slowly expand back to their desired shape...

i don't know that they'll crack but i was honestly concerned at what i saw on his boat and lets face it... the tanks on a MC is basically the same thing just a bit different shape

so word to the wise... when emptying just take a plug out of one of the vents on the bags when they get low so plenty of air can get in and the bag it doesn't suck part of the bag into the drain hole and create a closed suction on your hard tank and turn it into a a giant ballast vacuum

03-13-2009, 10:10 AM
that makes sense. so I guess the only time you would want to use check valves is if you T'd off the fill/drain lines of the tanks or had independent pumps filling sacs. the check valves would be benefical when just draining a independent sac, not a sac via overflow from tank