Siphon VS. Pump

I hope this is okay to post.. it's a great example of how the overflow works.. If not please remove it mods.

All credit goes to Melev:

 

The overflow, provided it is sized correctly will laways balace itself with the pumping rate.
The pump controls everything. It is far better to control a pumping rate with an inline valve than to use a teen and valve to return excess flow to the sump. A centrifugal pump only draws the power required to do the work at hand, plus a little for electrical and hydraulic inefficinecies, so adding additional head with an inline valve actually reduces electrical consumption. Pumps work well with the additional head and it does not cause undue wear or damage.
Returning flow to the sump via a tee and valve actualy makes the pump work harder, thus higher electrical consumption since it is pumping more flow (more work) and is also creating more heat. Its not an easy concept to grasp but its the way it works.

 

aha! i thought there was something about the head pressure being a good thing

 

Totally agree!!! but with my past xp with ball valve, and the more control you get. I feel that the gate is the way to go. I hate ball valves

 

I have no idea how you guys consider a gate valve easier to control. It's not a linear amount of flow that's changed with each degree of turn like a ball valve is. In fact, gate valves aren't designed to do more than "on" and "off".

And from Wikipedia:
"Most of the flow change occurs near shutoff with a relatively high fluid velocity causing disk and seat wear and eventual leakage if used to regulate flow."

 

Not totally true, the pump doesnt work harder then if you didnt have any valve. It works at its max. And the power consumption is reduced, but in a very very little amount. basicly, put a valve on it, with or without a tee, and you will be ok. If it is inline the further you put it from the pump the better it is for the pump, there will be back pressure. which is bad for the pump

 

Just my experiance, that the flow rate is easier to dial in the the ball valve. Mostly due to the style of "handles". But they do wear out sooner

I wouldnt put to much trust into Wikipedia....

 

Ah, you were the one who had this discussion the last time with AZDR, now weren't you?

Back pressure will NOT hurt a pump, period. I can attest to that. If it would hurt the motor itself, the Dremel and all similar tools wouldn't exist. The only thing that might happen is increased microscopic impeller wear because of the lower likelihood of a suspended solid hitting it.

I would put it farther from the pump so the PSI of the line itself from the backpressure is lower, not because of any concern for the pump.

 

I would when I've seen gate valves fail because of idiots using them instead of a handle to control the flow of their hose outside....

 

Yeah it was POWERMAN, who in my opinion was not 100% right, nor was I. There was a gray zone where I feel my test fell into. Plus some of my info was coming directly from the manufacture.

This is what I was what I was saying. But the manufacture was the one that told me their pump could be damaged from the higher PSI build up close to the pump. And as POWERMAN said, all the pumps are the same no matter who makes them. Believe what you want too... or ask Wikipedia ;D