Check valve placement

[adamsjstt]

My ballast install plan has changed and I'm now going to use tsunami 1200 pumps. My questions (which will be one of many) is that where is the best place to put the checkvalves? Close to the pumps or close to the bags? High or keep them low? I will be using one thru hull for vent and outlet, which are mounted forward under the windshield so I will be using 3 c/v per sack.

[chpthril]

Vent line c/v: anywhere between the sac and the T if you plan to have the vent and drain share a thru-hull.

Drain line c/v: serves no real purpose. Especially if the line is either running forward or across the boat.

Fill line c/v: I typically do not use a c/v here when using aerators, especially in the deeper hulled boats like the Ve or RZ series. It can cause the pump to vapor lock. When the boat is pulled from the water, all the water on the inlet side of the c/v drain out, leaving water on the outlet (sac) side of the c/v. When the boat is launched again, air is trapped in the line between the thru-hull and c/v. The water on the other side of the c/v adds head pressure. This can be enough weight to prevent the c/v from opening and purging that trapped air from the pump. If that air does not purge, the pump may not prime. Having the pump as low in the bilge as possible will increase the water pressure, cause its below the water line, thus counter acting the headpressure of the trapped air. So, if passive draining through the fill line is the issue, an anti-siphon valve works better.

[adamsjstt]

Vent line c/v: anywhere between the sac and the T if you plan to have the vent and drain share a thru-hull.

Drain line c/v: serves no real purpose. Especially if the line is either running forward or across the boat.

Fill line c/v: I typically do not use a c/v here when using aerators, especially in the deeper hulled boats like the Ve or RZ series. It can cause the pump to vapor lock. When the boat is pulled from the water, all the water on the inlet side of the c/v drain out, leaving water on the outlet (sac) side of the c/v. When the boat is launched again, air is trapped in the line between the thru-hull and c/v. The water on the other side of the c/v adds head pressure. This can be enough weight to prevent the c/v from opening and purging that trapped air from the pump. If that air does not purge, the pump may not prime. Having the pump as low in the bilge as possible will increase the water pressure, cause its below the water line, thus counter acting the headpressure of the trapped air. So, if passive draining through the fill line is the issue, an anti-siphon valve works better.

That makes since and saves me money. Do you incounter passive draing thru the intake often? If it is a common issue I would like to just add a c/v or anti-siphon the first go around.I want to do this install once and not have to add or take things away. Im sure you have tried but what if the fill c/v is mounted at the high point and as close to the bag as possible? If it was mounted at the high point the water would flow out of the hose in both directions. Dont no why but i dont like the idea of a anti-siphon but if that is what works then i will go that route.

[jason@wakemakers.com]

You definitely will encounter passive draining in bags in the rear of the boat. May not be a significant amount, and may be limited to certain situations, but it will occur without a device in place to prevent it.

A vented loop is overkill for the rear bags, just use a check valve, and install it at the high point in the rear hose. In that configuration we never encounter air-locking of the pump. Vapor lock is when a fluid boils in a closed system creating, appropriately enough vapor, which almost all pumps are incapable of clearing. This typically happens in the fuel system, and could never really occur in a ballast system.

[chpthril]

Vapor lock is when a fluid boils in a closed system creating, appropriately enough vapor, which almost all pumps are incapable of clearing. This typically happens in the fuel system, and could never really occur in a ballast system.

Ummm, actually, we could get water to boil in a ballast system. Water boils at 212F at sea-level. At sea-level, the atmospheric pressure 14.7PSI. As the pressure drops, such as gaining altitude, water will boil at a lower temp. So, how does this relate to a boat and ballast system one might ask? Well, a pump with a spinning impeller, such as an aerator pump, has a high pressure area on the output side of the impeller and a low pressure area on the inlet side of the impeller. Anyone ever wonder why the paint peels on a prop? Its boiled off due to the low pressure side, i.e. vacuum. There is such a vacuum that the pressure drop enough to actually boil water. Now, will we actually have boiling water in our ballast systems, no, but in theory, it could.

Now back to the topic of vapor-lock. The air trapped in the lines is the same air we breath. Its made up of mainly Nitrogen, Oxygen, Argon, Carbon dioxide as well as others. These are all called gasses.

Vapor: a substance in the gaseous state as distinguished from the liquid or solid state

So, I dont think its too much of a stretch to say that air trapped in the body of a pump is "Vapor-Lock", even though it didnt boil first. This is a real problem in ballast system. Ive seen it and addressed it in OEM systems using check-valves in the fill lines. Here is an example: Tige used to place the ballast manifold intake in the transom. Upon launching, air would be trapped in the ballast manifold. The orientation and weight of the flapper, with water trapped on top, would prevent the air from purging out of the manifold through the pumps. This prevented the pumps from priming. The short term fix was to goose it in reverse. This forced the water through the pumps purging the air. Long term was to relocate/reorient the c/v. So call it what you want, its real.

[duffymahoney]

In aerator systems I always put check valves on everything. The goal is to keep air out. I like having aerators installed through the rear transom. That way if they do get air in them, you can put the boat in reverse for a quick second and prime them. The tsunami 1200 suck! I would stay away, their thread is strange and hard to adapt. I would use the rule 1100. Easier to adapt and the loss of 100gph won't matter. Especially since the 1-1/4 tsunami 1200 most people size down to say and 1".

[chpthril]

In aerator systems I always put check valves on everything. The goal is to keep air out. I like having aerators installed through the rear transom. That way if they do get air in them, you can put the boat in reverse for a quick second and prime them. The tsunami 1200 suck! I would stay away, their thread is strange and hard to adapt. I would use the rule 1100. Easier to adapt and the loss of 100gph won't matter. Especially since the 1-1/4 tsunami 1200 most people size down to say and 1".

Actually, Attwood now has a T1200 with a 1" NPT inlet.

The Rule 1100 is actually faster then the T1200, so its a gain, not a loss

and the original T1200 has a 1.125" straight thread inlet, not 1.25"

[duffymahoney]

Wow when did the t1200 change to 1" NPT? That's awesome, the old thread was terrible for adapting. If anyone has aerator questions I have installed- designed a few and have learned a lot through trial and error.

[chpthril]

Wow when did the t1200 change to 1" NPT? That's awesome, the old thread was terrible for adapting. If anyone has aerator questions I have installed- designed a few and have learned a lot through trial and error.

Well, back in 09, it was rumored that there was one. I talked to two people with Attwood. Both stated that there was not a T1200 with 1" threads and that one was not in the future either. So, sometime since, it was actually put into production. Attwood part number 4663-1.

[duffymahoney]

So far rule pumps have been great. I am using 2- 1100 to fill my bow and 2- to drain my bow sacs and 2 rule 3800's to fill my rears and 2 -3800's to drain the rear sacs.

[duffymahoney]

I might install 2-1100's as crossover pumps between my custom sacs to get my transfer time down to below 4 minutes. I switch sides a lot while surfing. Say 4-5 times a day.

[adamsjstt]

In aerator systems I always put check valves on everything. The goal is to keep air out. I like having aerators installed through the rear transom. That way if they do get air in them, you can put the boat in reverse for a quick second and prime them. The tsunami 1200 suck! I would stay away, their thread is strange and hard to adapt. I would use the rule 1100. Easier to adapt and the loss of 100gph won't matter. Especially since the 1-1/4 tsunami 1200 most people size down to say and 1".

I already purchased the tsunami (with the 1 "NPT inlet) I looked at the rule but haven't heard anything bad about the tsunami besides the odd inlet size but with the 1" inlet and the cost I figured they would work just fine. I no you have a lot of experience with ballast installs actually one of your comments about impellar pumps is one of the reasons I went with aerators. This is my first ballast install and I want to do it right the first time so any info you can share will be great.

[duffymahoney]

Ask some questions. The folks at wakemakers know their stuff as well as some great folks on this forum.

[duffymahoney]

Tsunamis are great pumps. Especially since the changed the thread.