Ball Valve or Gate Valve??

[rcmike]

Unless you shut down the output an extreme amount there will still be enough water flowing through to adequately cool and lubricate the impellers. If you close the output by half or so you will be fine.

BTW, if you are using smaller pipe, pumping a few feet higher, or use a lot of elbows it is doing the same thing as closing down a valve. All of that increases head pressure.

 

[Salty1962]

Gate on return and ball on manifold.

 

[Turbo's Aquatics Verified Sponsor]

I'll throw in that all ball valves are not alike. I use a Cepex ball valve on my BA overflow siphon line, it's 1.5" and since you can loosen the nuts and it has a big handle, you can easily fine tune that beast and then tighten the nut down and lock it in. I tighten it down just enough that I can move it with like 1mm at a time with just the right pressure applied and it will stay wherever I put it.

 

[AZDesertRat]

Research Bernoullis Principle and The Laws of Affinity. Both have to do with centrifugal pumps and both prove power consumption goes down when you restrict the discharge side of a centrifugal pump. The pump is doing less work since it is not pumping as much water. Centrifugal pumps are very different from positive displacement pumps, they are actually more like a fan moving air.
It is very simple to prove this with a $25 Kill A Watt meter. Hard to grasp but thats the way it works. Putting a tee and valve on the discharge and returning water to the sump is counter productive since you are consuming the energy to pump that wasted water then dumping it. More power, higher heat generation, more noise and harder on the pump.

Commercial, Industrial and Municipal pumps have been using pump control and pressure reducing valves for decades and decades to control flows and pressures and the pumps are not hurt in the least.

 

[lavoisier]

Only other suggestion I would add is to buy high quality valves, whether gate or ball. Higher cost up front but you will happy you spent the money in a couple of years.

 

[Brew12]

Yeah I know but I was just trying to figure how it would work. as a pump spins it creates friction in the water and pipe. if you restrict the output it creates more friction which generates heat. If you don't slow the rpms, and you kept that going long enough the heat could build up enough to where the water can reach the boiling point which causes cavitation as well (once again I am talking a large pump so I know it probably would not get to that extreme in a aquarium pump), but it stands to reason that the water would still heat up a little thus decreasing the life of the pump. but like I said I might be totally off base with an aquarium pump. When I first started I was told that you should match the size of your return pump to the gph you were trying to achieve and not over size it and gate down (or get a DC pump that you can control the speed which is what I did) because it decreases the lifespan of the pump, and I just assumed it was for these reasons.

A pump with generate heat at maximum flow or minimum flow. The reason you may notice pumps heating up when you throttle back flow isn't that the pump is adding more heat to the system. The issue is that the reduced flow is removing less of that heat from the pump. The pump is producing a little less heat but a significant amount less heat is being removed from the pump. You are also removing less heat from the system piping when mass flow rate goes down. For that reason it is a good practice to never operate a pump at less than 50% capacity for extended periods of time unless specifically designed to do so.

 

[Ocelaris]

Not a huge fan of the home depot ball valves, they're rather hard to turn. I worry they'll go bad at some point, but they're cheap. Anyone else spend money on good ones to compare? The Spears gate valves are nice and I tweak them all the time

 

[saltyhog]

I'll echo that for any of the less expensive ball valves. I've had more than one that would not turn all the way off. Very irritating when it's to the manifold to your GFO and carbon reactors. Have to use their control valves to shut off flow when changing media.

 

[john.m.cole3]

Just the opposite. Gate for overflow and ball for return. Gates are usually more expensive but give you more control over the flow. You really don't want to gate down the return. its better to choose a pump the right size for the flow you are trying to obtain, that way you aren't putting stress on the pump. The over flow though you will gate down to match the return so you need more control over it.

+1, the only thing I would add is that I would not put a gate valve on my overflow if I didn't have a backup drain of some sort i.e. herbie, bean animal, etc...

 

[Reef4Rose]

From my research the pressurized pumps like Reeflo operate fine with valve restricted flow. It's the only way to dial them in for ideal flow. If I am misunderstood please advise as I am trying to decide between a D.C. and A.C. pump. The Elos overflow advises the ability to vary the flow to control noise.

 

[Brew12]

From my research the pressurized pumps like Reeflo operate fine with valve restricted flow. It's the only way to dial them in for ideal flow. If I am misunderstood please advise as I am trying to decide between a D.C. and A.C. pump. The Elos overflow advises the ability to vary the flow to control noise.

Most pumps will operate just fine with restricted flow as long as it isn't restricted too much. I'm a big fan of the Sicce AC pumps. More reliable than DC. The flow is partially adjustable on the inlet of the pump.

 

[Reef4Rose]

Reeflo states that ball valves are preferred and always restrict the discharge side never the inlet. Additionally the pump will work less when restricted and use less power. Another article I read said to use gate valves due to quality and more finite adjustability.