Closed loop problems

Tang-itis

New member
I had major leaking issues from my MAG7 but I think i've got them all figured out.
I can't get my closed loop pump to prime. I have a priming cap but when I pull it off water rushes out. Do i need to make the cap taller?

I've tried using a MJ pump to push water into it. I've tried blowing water through a tube to try to prime it. I've turned the pump on and off but I can't get it to run.

I've got a single 1" drain reduced to 3/4" with a 1/2" return going into 4 3/4" outlets. Is my plumbing too big or small?

Here is a picture of my setup. This is the first plumbing job I've done and I have changed it 4 or 5 times from paper to reality.

72076100_1795.jpg
 
Yes. Bring the cap up to an inch or two above the waterline. Then you will be able to fill it properly.
 
Do you have water in the tank? The picture does not show any in the overflow. Why do you need a fill cap? People use fill caps in their closed loop when they don't want to drill the tank. Its only needed when the pump intake goes up-n-over the tank wall. It looks like your pump intake is drilled about half way down the backside of the tank. As long as there is water above that bulkhead, the pump should prime itself. If anything, the riser tube and fill cap has air in it and wont let the pump prime properly.
 
Randy,
Yes, that's what I did.

I do have water in the tank but I had the return pump off.

I think my problem is either having a fill cap or not having enough back pressure. I put my hands over the two outlets that are on the back of the tank and the pump got quieter and there was actually flow out of the two that come to the front of the tank.

I think I'm going to get 4 1/2" loc-lines and see what happens with that.
 
I would get rid of the fill cap and riser. Its not needed. It may also be a source for micro bubbles in the system. Slowly close the ball valve on the output side of the pump while trying to prime it. See that helps priming. Open it once the pump catches prime.
 
I just don't see how your pump couldn't be 'primed' when this fill cap is above the display tank's waterline. In the pic below I outlined the plumbing that would be primed with water. Some air wouldn't stop the pump.

I'd bet that you just thought that you would get more flow from each return than you are getting. Do you think that is possible?

If you want sort of a 'jet flow' to come out of your returns you would need smaller plumbing or a bigger pump.

I've seen some closed loops incorporate a ball valve on each return so that you can regulate each individually.

closedloopproblem3.JPG
 
You've got a mag7 hooked to 1/2" plumbing, and then splitting to 4x3/4" outlets. SO the 1/2" probably cuts it down to about 300gph, and then you split that up to get 75gph out of each outlet. Blocking two of them moves twice the water out the other two.


A mag 7 should be running 1" to 1.5" plumbing at ALL points.
 
Not to wake everybody up abruptly... but a pump that has an intake below the surfave of the water does not need primed, it is already flooded.

This is evidenced by the fact that when he takes the "fill cap" (totally not needed) off, water floods out.

Second wake up call... since when do you have to add back pressure to rotary vane pump to get it to work?

Only answer.... there is something wrong with the pump. Otherwise it would be pumping.
 
<a href=showthread.php?s=&postid=7780726#post7780726 target=_blank>Originally posted</a> by Tang-itis
put my hands over the two outlets that are on the back of the tank and the pump got quieter and there was actually flow out of the two that come to the front of the tank.

Bean, I think it is pumping. I think hes just getting like 40gph out of each 3/4" outlet.
 
I think, well, i know it is pumping now I just haven't been able to get all the air out of it and quiet it down where it should be.

I just need to figure out how to get the kind of flow I was expecting. I am expecting to get more flow out of it than my Mag 5 that is my sump return.

I read that if I want jet flow then I should get smaller plumbing and I read that I shouldn't have less than 1" plumbing. My first guess would be to reduce the plumbing size.

Why would they be made with 1/2 inch inlet and outlets if they needed 1 inch plumbing?

I guess back pressure wasn't the right term? I just seems that if I had more back pressure on the pump I would get more flow.
 
Tang-itis, when I said "reduce the plumbing" I meant to say reduce the outlet sizes (like a nozzle". That would give you a more forceful output, but not increase the gph rate if you know what I mean. Sorry for that confusion.

Duhhh everyone else is absolutely correct, no fill pipe is necessary since it is below water level anyway. I do know what you mean by noise. I had a Mag pump before, it made a rattling sound that I couldn't live with so I sent it back. I heard that they have a problem with salt creep too (when plumbed externally).

A pump actually gets the most flow when submerged and used ‘like a power head’ which has no restriction which equals no back pressure what so ever. The more plumbing, smaller the plumbing, 90 degree angles, and length after the output of the pump will give you more back pressure and less gph flow.
 
I assume it's like sucking something through a straw though. If you try to drink something through a coffee stirer you're not going to get anywhere and if you try to drink through a piece of 1 inch pvc you're going to have a hard time as well but if you drink through a normal straw your fine.

I think I'm going to try the loc-line and if I'm not happy...I'll go pump shopping.
 
Ahh okay... I missed that sentace about "then flow came out".

In any case with a pump that small and the way it is plumbed.... well it's just not going to behave well, let alone give you much flow out of the ports. I would suggest an ocean motions squirt, and or a larger pump.
 
The problem is that the pump is too small for the plumbing.

You are getting some flow, but it's only flowing out through the two penetrations in the back.

There is not enough pressure on the output of the pump to 'lift' enough water to the two upper returns.

Plug the two returns in the back of the tank, and see if you can get any flow to come out the top.

Stu
 
<a href=showthread.php?s=&postid=7783516#post7783516 target=_blank>Originally posted</a> by stugray
The problem is that the pump is too small for the plumbing.

You are getting some flow, but it's only flowing out through the two penetrations in the back.

There is not enough pressure on the output of the pump to 'lift' enough water to the two upper returns.

Plug the two returns in the back of the tank, and see if you can get any flow to come out the top.

Stu

I thought he said he was getting flow from the top 2 pipes but not the 2 that go through the back of the tank..Oh so confusing.

I agree with the rest, get rid of the fill pipe. Then use 3/4" for your pump feed line and 1/2" for your returns. You will push water will more force that way.
 
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