Combining pumps in parallel and series


Joined
Sep 18, 2020
Messages
933
Reaction score
524
Location
Pacific NW
Hardiness Zone
8b
Country
United States
I don't know if this is such a groundbreaking idea, but it's kind of blowing my mind:


Basically, you can plumb two pumps in parallel to get double the flow at the same head or plumb them in series to get the same flow at double the head.

From what I know about electricity and how you can manipulate circuits to get whatever amperage or wattage you need, I always wondered if pumps worked similarly, and it looks like they do.

For 90% of folks building small garden ponds, this is probably useless knowledge, but it could really come in handy in specific scenarios where you have very high head height to overcome (put two or more pumps in series to increase their lifting capacities) or high flow needs (put them in parallel to get more water out the end of your pipe).

Really high flow and high head pumps seem to be very expensive and incredibly power hungry. Using this knowledge, you can use two or more pumps that, on their own, wouldn't get the job done but when combined together can do it more efficiently than one monster pump.
 
Ad

Advertisements

Joined
Sep 18, 2020
Messages
933
Reaction score
524
Location
Pacific NW
Hardiness Zone
8b
Country
United States
Here's an example of this concept in action when running multiple pumps in parallel. I pulled this chart (see below) from a series of pumps on The Pond Guy store.

The 2100gph pump uses 86 watts of energy. The 7800gph uses 607 watts. How many small pumps would it take to get the same flow as the big one? 7800 / 2100 = 3.7. So, we buy 4 small pumps instead. Now we're doing 8400gph for 86 watts x 4 = 344 watts. That's 10% more flow for 57% of the energy.

What does that look like for your power bill? Average cost of a kwh in the US is $0.132. In one month, the big pump will cost $58 to run. The 4 small pumps will cost $33. Difference of $25/month or $300/year or $1500 lifetime energy savings if you expect the pump to last 5 years. Savings gets better and better the longer they last.

Imagine if you lived in Hawaii where the electric cost is 3x national average.

There's another benefit: redundancy. If you run your whole pond system on one big pump and that pump dies, you instantly go from 7800gph to 0gph instantly. Big problem! If you run it on 4 small pumps and one dies... you lose 25% of your flow and hardly notice. Maybe think about replacing the dead one after you get back from your next vacation.

Caveat: You will see in the image below that the big pump works at over 2x the head pressure of the small one, so if you were planning to buy from this series of pumps, this example would only work if you have very low total dynamic head (ie. low or no waterfall and short runs of large pipe).


Screen Shot 2021-06-03 at 2.40.37 PM.png
 
Joined
Dec 16, 2017
Messages
6,723
Reaction score
4,866
Location
Ct
Hardiness Zone
6b
Country
United States
Not my idea of a task worth the effort. i believe you will shorten the lives of the pumps. even iff the same pump in time one will start to slow while the other may not at all. I have been involved in multiple projects from hospitals hotels schools and residence and i have never see a call for in series pumps on the same lines. Even city water lines have pumping stations and if i am not mistaken even those have holding tanks. i do know water dept guys now you got me thinking and will ask.
 
Joined
Sep 18, 2020
Messages
933
Reaction score
524
Location
Pacific NW
Hardiness Zone
8b
Country
United States
I th
Not my idea of a task worth the effort. i believe you will shorten the lives of the pumps. even iff the same pump in time one will start to slow while the other may not at all. I have been involved in multiple projects from hospitals hotels schools and residence and i have never see a call for in series pumps on the same lines. Even city water lines have pumping stations and if i am not mistaken even those have holding tanks. i do know water dept guys now you got me thinking and will ask.
I think you will see this strategy employed more in municipal water / storm water management / and industrial systems where the size of pump needed would be prohibitively expensive and/or pumps need to be able to be serviced without shutting down production.
 
Ad

Advertisements

Ad

Advertisements

Joined
Nov 16, 2021
Messages
13
Reaction score
9
Country
Spain
Very interesting. I have two pumps in parallel, one electric and one solar. I had the feeling that when the two worked together they gave more flow than when they worked individually. This is demonstrated with calculations.
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Top