Plumbing question

[Reedman]

Alright,
so I have my ampmaster plumbed up (Closed Loop), but I am thinking I might be restricting the output a little too much. Here's what is happening. I have 1.5" out of the AM3K to a T fitting where it reduces to 2 1" lines. One of the lines runs into the tank, the other splits to 2 1" lines, each into the tank. I run all of them wide open (3 1" outputs in the tank). If I open the output of the AM3K all the way I get microbubbles in the tank out of the closed loop. If I restrict the output of the AM3K slightly I get no bubbles, but some occational noise out of the pump.

Any ideas on this? Would changing the first T from 2 1" outs to 1 1" out and 1 1.5" out help?

I'm at a loss here, and I really don't want to ruin the pump.

Thanks for the help everyone.
-Reed

[thefatman]

hmm only thing i can think of off hand is that it's pulling in air from somewhere. maybe on of the t's has a micro leak, that is sucking air in when it's opened all the way?

i've never plumbed a cls yet, so i could be way off base, just taking a stab in the dark.

[Geoff]

Jay has the most likely cause. if there is a micro leak you have for all intensive purposes made a DIY venturi valve.

another possibility is that when it is wide open the flow is so great that at the intake small funnels from the surface could be created. you would prolly see a lot more bubbles if this were the case though.

i would check for leaks.

G~

[Reedman]

DOH! I was hoping that wasn't the feedback I'd get. But then again, the truth is never fun. I will check for leaks in the plubing, as the intakes are down near the middle of the tank & I see no way they could introduce air into the lines.

Thanks guys, really appreciate it.

-Reed

[ReefDave]

Reedman, your not looking for leaks underwater near the intake you are looking for leaks where the return comes from the pump....if the leak is underwater you are right there would be no air "sucked in".

[Reedman]

Thanks Dave. I just reread my post and see that my grasp of english is diminishing quickly

I was trying to say that the funneling possibility that Geoff suggested isn't really possible in my tank because of how low the intakes are.

I will check all of the exposed plumbing for small leaks. I am guessing I have a very small leak at a joint that is letting a little air in the line when high flow creates enough suction.

Thanks again.
-Reed

[Xwild]

Reed.. just go over all the joints with another layer of pvc cement.. goop it on good..

Also, reducing from 1 1.5" line to 2 1" lines is probably adding some restriction..

1.5" line has 1.766 square inches of area...
1" line has .785 square inches of area..
so 2 1" lines is 1.57 square inches.. not a huge difference, but it is some, if you're concerned with head buildup..

[mojoreef]

Boy and you design airplanes, I may never fly again

Reed you got an air leak for sure. after a few day you will see some salt creep, this should tell you what is happening. Also do u use locline


Mike

[Reedman]

Yep. I have a little salt creep at a joint. I will clean & dry it, use some primer, then some PVC cement to (cross fingers) seal that baby up.

I don't "design" airplanes, just help in designing airplanes...so please...keep flying

I used to use loc-line, but I like the larger outputs better, so I noow have loc-line in the garage with other miscilaneous plumbing parts for the next tank (don't tell my wife).

[Buehlz]

not sure if you guys know this but when doing plumbing with PVC tubing you use the primer/cleaner on the ID and OD of the joint being glued and make sure the cleaner is competly dry... then goop on the glue on the inside of the joint... after you have pushed the joint togeather as far as it goes always give the tube a 2"- 4" turn (helps the glue seal). learned this doing plumbing on in ground swimming pools for 2 years. Please dont take this as an insult if you have experience at glueing PVC

[mojoreef]

Buehlz good advice is never frowned upon here my friend, thanks for the tip. Myself I am lasy and use the ho glue that doesnt need primer.


mike

[Reedman]

Thanks for the tip Buehlz. I'll use it on the next project.

So I can here air in the pump when I open it up. I am assuming that this means that the air is being introduced on the intake side of the pump (thinking out loud here). Does this make sense??

If that is the case my search for a leak is much smaller.

Thanks everyone.

[thefatman]

lol i like using the purple primer and then the cement. cuz it has a purtie color

thanks buehlz, i have heard, and always do, twist the joint after htey have been pressed together. but i did not know it should be 2" to 4" i have just always given it about 1/4 turn one way, then 1/4 turn back.

but i have also only glued minimal things thus far. as i'll be gluign together my cls tommorrow, thanks for the advice!

[thefatman]

reedman, yup, that's where i would start looking first. if yo udont find anything on the intake side, well then you know what's next

[Reedman]

Alrighty then,

I hate to belabor this, but I checked all of the joints on the intake side of the pump (there aren't many) and found no leaks. I can hear air mixed in the water flow through the pump, so I am confident that the intoduction of air is on the intake side. When I throttle the output back a little I loose the bubbles, but the pump begins to make some noises that I really don't like (I'm thinking it may be cavitating).

Here's my question. For a pump to cavitate you need to be starving the pump, correct? I am running 1.5" plumbing on the intake side and T it off at the end to limit the suction effect (2 1.5" strainers). This shouldn't starve the pump, I wouldn't think.

Please throw out your suggestions. I'm getting real sick of redoing my redone plumbing.

Thanks all. You guys (and gals) are the best.

-Reed