Wet dry question

  • We are currently upgrading MFK. thanks! -neo
Volenti;1065490; said:
they'll draw less power fully restricted than running wide open.
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Are you sure? Power consumption will be the same surely? How does the pump know its constricted. If anything I would have thought restricting would increase power consumption. Not to belabour the point, but why reduce pump output even if the pump allows? Electricity cost is still the same so you might as well utilise the extra flow efficiently. Just run it back through the filter.

Anyway, reduce output or run a T back to sump in response to origional post.
 
Here we go again. :)

We did a thread on this already. It is fact that when you restrict the discharge of a centrifugal pump the pump will consume less energy as it is doing less work (moving less water). It also will put off less heat.

Let me go find the link.
 
I had a quick read of that link (thanks) and the general concensus seemed to be to add a T piece.

My pump shop guy (yes I buy lots of water pumps for many applications) who is very experienced tells me the electricity consumption will be the same on centrifical pumps regardless of flow/constriction - They are a motor unit with attached impellar. Thats what I mean by energy usage, I am talking electricity cost in dollars. Looking at the linked thread they are discussing WORK and heat which are physics terms although they are also measured as energy units.

Does it really matter? I would add a T in this case but others may not.
 
Your shop guy is wrong. Sorry but he is.

Our pumps at the plant consumed less electricity when choked back. A couple of guys also tested it at home in that thread.

i put the amp clamp on one leg of a 3/4hp march pump ( 220v3p)

it read 2 amps open, choked down it read 1 amp
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Regarding actual data, I have a little 12v magdrive pump running my 10 gal setup (it's actually designed for PC watercooling, high head, low flow) in normal running mode it draws 1.05A, with it's outlet blocked it draws 0.84A.
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Does it really matter? No, you can do what every suits your needs.
 
Bud8Fan,
If you say you have measured the current draw yourself, then I believe you.
However, I would still use a T to divert extra flow in this case.
 
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