over the top CLS holding prime question

[ste6168]

hey everyone, i posted this in the DIY section also but have yet to get much response so here is my question....

Alright so i was thinking and i drew up a little diagram to show you guys exactly what i mean. Just like in the picture below will the pump hold prime druing a power outage if it is placed above the tank like this? Also are there any better ways of doing this without the pump being below the water level as i do not have room?

Thanks, Mike

 

[goulding.c]

I would think it would loose prime unless you put on a check valve on the other side of it. That way the air couldn't draw back through when power is lost. I like the picture. Is this for just circulation? I have a125 and I am tired of looking at the 3 pumps sitting on the rock and my flow is all one big whirl pool. I was thinking of doing this same thing with a a pvc ring around the top with the adjustable returns.

PS I hate it when no one replys when you are itching for help!

 

[goulding.c]

Dude, I just noticed your in the burgh too! Thats sweat. Where are you a student? I'm in wexford area.

 

[ste6168]

im a tech ed student at cal u, origianlly from shaler/north hills area. About 8 minutes away from seahorse on route 8.

 

[TitansFan]

So no room to attach a small shelf to the back of the stand right below the tank?

 

[ste6168]

there is but it would be really hard to attach down there, and anyway i dont want it there.

 

[goulding.c]

ste6168 I am in wexford drad of NA. One of my employees graduated from shaler afew years ago though, Pluncket.

Back to the topic, can you get a check valve in 1inch pvc that is not brass or copper? I'm sure you can, that would hold water in the pump just like the trick with a straw when you put your thumb over it and pull it out of the cup. How load is the pump going to be above the tank? Is that an issue?

 

[ste6168]

the shelf the pump will sit on will be at about the same exact height as the lip of the tank.

 

[piranhaking]

if im looking at that right all the open ends of the pipes are underwater If they are all under water then it cant loose prime. pumps lose prime when air gets into the lines. If all lines are under water air cant get in them. The reason HOB overflows and filters lose prime is because they suck the water out of the compartment and the open end of the pipe is exposed to air. If the ends cant suck in air, it cant loose prime.

 

[twon8]

i think the problem you will have is getting it primed. it shouldn't lose prime in a power outage, but ?

 

[piranhaking]

well, to prime it plug all but one of the outlets and then put an air line in the other one and draw the air out of it, much like priming an overflow box. You could also probably take another powerhead and put the outlet over the inlet and then try to seal the connection with your hand and it would probably be enough flow to start things.

 

[melev]

Could you lower that shelf just a few inches, to get the intake of the pump just below the water level? You'd still need to prime it the first time, but you'd never need to worry about checkvalves or anti-siphon holes. Just lower that shelf 4 - 5".

 

[orlenz]

you can tap your main return into it with a ball valve to prime it.