Quote Originally Posted by Senater_Cache View Post
just to get this straight without starting anything... are you sure?
how can there be more flow if the pumps are in series and all impellers are moving at the same speed?

now if they were in parallel, then there would be more flow as the water path get divided into three, with each third being "moved along" individually (as individual as it can get in a closed loop
am I misunderstanding this?
Yes im fairly sure... the last number we talked about tho was near 30% i think.
I got bit in the butt when i challenged scott to this statement, and he showed it to me.
That's why i know...

And vapor said it best...

Quote Originally Posted by Vapor View Post
The approximation I use is as follows:

When going from single pump to dual pump (identical pumps), you can expect roughly (X * sqrt(2)) for flowrate, where X is your flowrate with single pump. Works out to a ~40% increase in flowrate.

You can apply this when going from dual to triple as well as single to triple, either (X * sqrt(1.5)) or (X * sqrt(3)), depending on what your starting point is. From a single pump, that works out to a ~73% increase in flowrate; from a dual, that works out to be a ~22% increase in flowrate. What those flowrates mean for you thermally varies on your setup....usually the gains past dual DDC are almost non-existent, heck, going to dual DDC can hurt if you don't have enough radiator or if you block is blind to flowrates (some have a pretty flat response curve).