Closed loop

[Mal3]

<a href=showthread.php?s=&postid=11130668#post11130668 target=_blank>Originally posted</a> by Critter
Well, Quite1one found a 6000 for me... hooked it up and after an hour it was too hot to hold your hand against. sigh. oh well, it was free. So now on to the next plan and follow Dan's advice. So Dan, give me some idea how your plumbing is run.. I remember the inlets with the penductors, but where was the pump you were using and what kind of plumbing do you have from the pump to the penductors. What is your rise etc? Thanks

Critter, you went from a QO4000 (1000 gph) to a QO6000 (1500gph). That is quite an increase. You are now trying to move more water through the 1" pipe than is possible. The bubbles is due to cavitation from restricted water supply. The pump must not be getting enough water. You are pulling over the top. There is no pressure feeding it, and now that you have a larger pump, it must be starving and it is causing it go get warm because it is working extra hard. I use these pumps with closed loops, drilling the tanks and have no problems like this. I have never used them over the top. I use a 1.5" intake on a QO 6000. That is much different than what you have here. My pipe lengths are short. One inch pipe will not handle 1500+ gph. Therefore, by design, you are starving that pump for water and that makes them heat up from the friction. I had a sequence pump do the same thing in a similar set of circumstances. It was a high speed pump (8500 gph) and it was heating up and cavitating because it was not getting enough water. I went to a smaller pump because there was not enough water pressure due to my supply lines being too small without any pressure.

If you want to test the pump, put it in a rubbermaid with fresh water and run it. See if it gets hot in the same period of time as on your tank. If not, then it is the plumbing.

You may actually need to use 1.5" pipe right up to the pump to draw enough to feed the pump because you are going over the top. I have not tried over the top, but that is the best solution I can offer.

I have had these pumps run small closed loops like this for as long as 3 years - no problem. I use 1" on a QO 4000.

I see some people saying these pumps are not good or do not work. How you engineer the water flow and plumbing can make a HUGE difference. If the plumbing is not right, you can burn out any pump because you are making it work harder than needed. They are not heavy duty like a sequence or some others. Of course, they cost less too. But they can do the job if set up properly.

Another suggestion is to raise it up by shortening the intake and return pipes to reduce the head pressure from coming over the top. Also, you are right about having a 90 right at the intake. That does cut down the intake flow. If you do go to 1.5" plumbing, use a slow 90, not a hard one, and leave 6 to 8" of pipe before you add the 90. OR you can turn the pump intake and not use the 90 on the intake. Go straight in.

You can put the pvc together with plumbing tape to make a trial before you glue it up. Then run it and see if it still heats up before you glue the pipe. If it still does not work, at least you can return the fittings to the store.

Good luck.

 

[krikor]

Plumbing does make a huge difference... but you saying there is no pressure when comming over the top of a tank is wrong.

He is creating a siphon, the pressure is equivelent to the ammount of pipe in the tank and that height of water above the intake... otherwise how would siphons work if there were no water pressure?

pulling over the top near the bottom of the tank is no difference than pulling from a hole in the tank at that height. Granted pushing it back over the top of the tank add's head because of the elbow's etc. on its way to the pump, the only thing constricting its flow to the pump is the pipe size.

 

[Critter]

Good information, though I have a 4000 and it acts exactly the same as the 6000 heat wise. Also, I've heard of increasing the size of the exit pipe but not the inlet.. but something to consider for sure. I would run it in water to test, but that wouldn't be a valid test because it would indeed run cooler in water so that won't help to determine if its the plumbing. Though it would tell me if the pump is sucking in air... Maybe I will try the 4000 and see how it deals with the plumbing as far as cavitation.
But I did remove the pvc from the inlet from the tank to the pump and replaced with clear 1" flexable tubing.. so right now its as good as its going to get. I can try removing the long tube down and just let the one inch pipe suck it in near the top of the water and see if that removes the cavitation... if its starving, then that would be the only place possable. Ie not enough or large enough holes in my pvc strainer. Anyway, i'm learning all kids of stuff... kinda messy, but thats the hobby.

<a href=showthread.php?s=&postid=11186472#post11186472 target=_blank>Originally posted</a> by Mal3
Critter, you went from a QO4000 (1000 gph) to a QO6000 (1500gph). That is quite an increase. You are now trying to move more water through the 1" pipe than is possible. The bubbles is due to cavitation from restricted water supply. The pump must not be getting enough water. You are pulling over the top. There is no pressure feeding it, and now that you have a larger pump, it must be starving and it is causing it go get warm because it is working extra hard. I use these pumps with closed loops, drilling the tanks and have no problems like this. I have never used them over the top. I use a 1.5" intake on a QO 6000. That is much different than what you have here. My pipe lengths are short. One inch pipe will not handle 1500+ gph. Therefore, by design, you are starving that pump for water and that makes them heat up from the friction. I had a sequence pump do the same thing in a similar set of circumstances. It was a high speed pump (8500 gph) and it was heating up and cavitating because it was not getting enough water. I went to a smaller pump because there was not enough water pressure due to my supply lines being too small without any pressure.

If you want to test the pump, put it in a rubbermaid with fresh water and run it. See if it gets hot in the same period of time as on your tank. If not, then it is the plumbing.

You may actually need to use 1.5" pipe right up to the pump to draw enough to feed the pump because you are going over the top. I have not tried over the top, but that is the best solution I can offer.

I have had these pumps run small closed loops like this for as long as 3 years - no problem. I use 1" on a QO 4000.

I see some people saying these pumps are not good or do not work. How you engineer the water flow and plumbing can make a HUGE difference. If the plumbing is not right, you can burn out any pump because you are making it work harder than needed. They are not heavy duty like a sequence or some others. Of course, they cost less too. But they can do the job if set up properly.

Another suggestion is to raise it up by shortening the intake and return pipes to reduce the head pressure from coming over the top. Also, you are right about having a 90 right at the intake. That does cut down the intake flow. If you do go to 1.5" plumbing, use a slow 90, not a hard one, and leave 6 to 8" of pipe before you add the 90. OR you can turn the pump intake and not use the 90 on the intake. Go straight in.

You can put the pvc together with plumbing tape to make a trial before you glue it up. Then run it and see if it still heats up before you glue the pipe. If it still does not work, at least you can return the fittings to the store.

Good luck.

 

[Mal3]

<a href=showthread.php?s=&postid=11196946#post11196946 target=_blank>Originally posted</a> by Critter
I would run it in water to test, but that wouldn't be a valid test because it would indeed run cooler in water so that won't help to determine if its the plumbing.

How did you conclude this? Try it in a bucket. If it heats up as much as you say without plumbing, it is the pump. If not, it is the plumbing.

All pumps do some heat transfer, but it should be very minor if all is right.

 

[krikor]

I know my via aqua's produce enough heat in a 5 gal bucket to keep the temp around 95-100....

you would notice if the temp in the water gets real hot real fast...

 

[Critter]

Hmm.. I thought you were referring to wether there would be a difference in the pump in the water as apposed to not in the water... I wasn't looking at it from the plumbing side. I see what your saying about just running it to see if its the pump or the plumbing.
Anyway... I currently have the 4000 hooked up. The plumbing I made for it, goes up then T;s off to both ends of the tank then goes up and over with 2 elbows in the water on each side. Its the same as in the first picture i posted, except the inlet is now about 15" to the right of the pump and I have clear tubing connecting the inlet and the pump. Its actually doing a pretty decent job. I have a ball valve on each side so I can regulate where the collision happens in the tank. After the holidays, I might make an adapter for the 6000 to run it on the same plumbing to see what the difference is.
I've had it hooked up like this 24/7 and it still gets hot, but its not melting down or anything.



QUOTE]<a href=showthread.php?s=&postid=11236117#post11236117 target=_blank>Originally posted</a> by Mal3
How did you conclude this? Try it in a bucket. If it heats up as much as you say without plumbing, it is the pump. If not, it is the plumbing.

All pumps do some heat transfer, but it should be very minor if all is right. [/QUOTE]

 

[bonedaddycjh]

I would like to see a picture of the front of the tank.

 

[Critter]

Its current state. I might paint the inlet pvc or just let the coraline cover it.. we'll see. the one maxi-streem (left) is comming out next.. the right one went out the other day.

<a href=showthread.php?s=&postid=11247037#post11247037 target=_blank>Originally posted</a> by bonedaddycjh
I would like to see a picture of the front of the tank.

 

[bonedaddycjh]

Very nice! Cant wait to see the finished product!!!

 

[bonedaddycjh]

Also, what size mag-float are you using? A 125?

 

[Critter]

Thanks... and yes I believe that is a 125. Hmm, maybe this winter I will put the tank cam back online.

<a href=showthread.php?s=&postid=11257143#post11257143 target=_blank>Originally posted</a> by bonedaddycjh
Also, what size mag-float are you using? A 125?

 

[bonedaddycjh]

How does that 125 work for you? Cause i had one on my 55 gallon tank and it didnt seem to work that well.

 

[Critter]

works great on all the basic stuff... for the coraline (like I have on my sides and back) I have one modified to use a razor blade. A guy in jersey makes them. its acrylic and you glue it to the mag-float. its amazing how well it works.

<a href=showthread.php?s=&postid=11265221#post11265221 target=_blank>Originally posted</a> by bonedaddycjh
How does that 125 work for you? Cause i had one on my 55 gallon tank and it didnt seem to work that well.

 

[bonedaddycjh]

How much did that run you? If you dont mind me asking.

 

[Critter]

I checked and it was 15.76 including shipping.

<a href=showthread.php?s=&postid=11273506#post11273506 target=_blank>Originally posted</a> by bonedaddycjh
How much did that run you? If you dont mind me asking.

 

[Mal3]

Hi Critter,

Nice tank. Very clean.

I see another problem. The intake tube is too restricted. Those drilled holes are too small. Take a new piece of pipe and use a chop saw to cut 4" of slots in the pipe each 1/8" with the saw. Cut down as far as you can without cutting through the pipe. Slots let in much more water than the small holes in the pipe. Feed the line more water!

Also, the "T" and each 90 you have on that line is costing you one foot of head on that pump. Based on what you said, I figure you added 8 90's and a T. That is 9 feet of head pressure. Whow!

You would do much better to have one point of entry back into the tank and split the line at the point of entry inside the tank.

<a href=showthread.php?s=&postid=11239121#post11239121 target=_blank>Originally posted</a> by Critter
Anyway... I currently have the 4000 hooked up. The plumbing I made for it, goes up then T;s off to both ends of the tank then goes up and over with 2 elbows in the water on each side. Its the same as in the first picture i posted, except the inlet is now about 15" to the right of the pump and I have clear tubing connecting the inlet and the pump. Its actually doing a pretty decent job. I have a ball valve on each side so I can regulate where the collision happens in the tank. After the holidays, I might make an adapter for the 6000 to run it on the same plumbing to see what the difference is.
I've had it hooked up like this 24/7 and it still gets hot, but its not melting down or anything.



QUOTE]<a href=showthread.php?s=&postid=11236117#post11236117 target=_blank>Originally posted</a> by Mal3
How did you conclude this? Try it in a bucket. If it heats up as much as you say without plumbing, it is the pump. If not, it is the plumbing.

All pumps do some heat transfer, but it should be very minor if all is right.

[/QUOTE]

 

[krikor]

I agree with trying to keep the line in 1 peice for as long as posible. personally i know i wouldnt want it split into the tank though (aestetics)... mabye split it right above the tank and angle your outlets down into the tank... If that makes any sense.

As far as head losses it depends.

Determining loss coefficients for pipe componts is as follows Headloss = K(V^2/2g)

K is the constant that depends on the part.

for example the K for an elbow with a short radius is 1.5 and for a T branching the flow is 2.

so a t contributes 33% more headloss to a system than an Elbow.

Thought he worst is definatly valves... a gatevalve fully open has a K of 10 while a ballvalve has a K of .005. Though when you get to 2/3rds closed the ballvalve jumps to 210 while the gatevalve is only 17.... (thats why gatevalves are better than ballvalves for skimmers/ pump flow control. ) (unions are awesome and add almost no head losses fyi)

Err sorry if i got techincal on ya...

 

[Critter]

Thanks... the holes run up and down the whole length, front, back and both sides. As good as its going to get for now. My setup isn't really condusive to going straight up and then splitting it off to each side. I go up about half way, then split to each side, then up the rest of the way and over. Best I can do for now. The flow is actually very good even with the head loss.

<a href=showthread.php?s=&postid=11302135#post11302135 target=_blank>Originally posted</a> by Mal3
Hi Critter,

Nice tank. Very clean.

I see another problem. The intake tube is too restricted. Those drilled holes are too small. Take a new piece of pipe and use a chop saw to cut 4" of slots in the pipe each 1/8" with the saw. Cut down as far as you can without cutting through the pipe. Slots let in much more water than the small holes in the pipe. Feed the line more water!

Also, the "T" and each 90 you have on that line is costing you one foot of head on that pump. Based on what you said, I figure you added 8 90's and a T. That is 9 feet of head pressure. Whow!

You would do much better to have one point of entry back into the tank and split the line at the point of entry inside the tank.

[/B][/QUOTE]