Anybody else do this?

[beaver962001]

Hi. I just got a used 120 gal last week with sump. The tank has dual overflows rated at 700 gph each. The return pump is only rated at 950 gph so instead of just upgrading the pump I bought one just like it so I'm running 2 950 gph pumps inline then splitting between each overflow. Has anybody else done this? How does it work for u? Will the pumps be fighting each other ran like this? I'm just wondering before I fill the tank this week...Thanks

 

[nazzman]

2 pump pushing into same pipe gives you the same flow rate as they are pushing against each other at the tee

 

[Rob Top1]

So you you have the two pumps plumbed to one line and then split again into two?
Plumbing two pumps into one line is fine, but the line it goes into should be larger. Two 3/4 pipes into a 1" line. Spilting those lines later seems counter productive.
Also the way your T is installed has a huge negative impact of flow. Both pumps have two hard 90s. This adds a lot of head pressure to the flow and reduces is rate. Using a wye would cause less head loss, another option would be to have your T installed as a side out. HTH

 

[welder1]

I would put check valves on each pump line. Just a thought :bigsmile:

 

[Rob Top1]

According to P. R. Escobar's Aquatica System Engineering when two pumps are plumbed in parallel there is not an increase in pressure but there is an increase in flow. He writes about the importance of pipe diameter having an increase to the shared pipes diameter. Personally I would redo the plumbing, sorry. But you will achieve better flow by having two lines, each pump going to its own overflow or plumb the two pumps in parallel the shared line should be of a greater diameter.

 

[beaver962001]

Thanks for the your input. The lines connecting the pumps r 3/4. The tee that connects them is 1" and it continues 1" to the overflows. I may redo it. I'll prolly see how it does first tho...

 

[JoeIII]

Befor you "go live" simulate a single pump failure - it is possible that in teh event of a single pump failure the other pump would end up recirculating drictly back into the sump backwards through the failed pump, instead of giving you half the flow to the display like you may expect. The real value of having two pumps is that redundancy, where if one fails you still have flow to the display.

 

[beaver962001]

Definetly. Lol. That could be a disaster

 

[welder1]

That is my reasoning for check valves at the pumps if one fails the check valve would keep it from recirculating thru the other pump.
And if you have a power failure it would not back siphon when the pump stops.