Pressure on low speed?

Rangeball

Well-known member
May 25, 2007
785
Have my new 3/4hp whisperflo dual speed up and running. Previous dynamo only gave me about 8 psi on my gauge, WF is giving me 14 on high. However, on low speed it's only reading about 2-3 psi. Is this normal?
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,430
Pleasanton, CA
Low speed PSI is about 1/4 of the high speed so that is probably about right. Plus gauges tend lose some accuracy at low PSI. The increase from the Dynamo is likely due to the 3/4 HP Whisperflo having a higher flow rate than the Dynamo.
 

Rangeball

Well-known member
May 25, 2007
785
Thanks fellas.

mas, from memory, it seems like it modeled pretty darn close to what you predicted way back when... nice job :)

My pool is old, and it only has a skimmer, a main drain and one return. I have never had an eyeball in my one return, just the 1.5" fitting. If I restrict that down to say, .75", to increase circulation on low speed, any reason not to do so? The gauge doesn't change when I manually restrict the flow...
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,430
Pleasanton, CA
Restricting the return will increase the exit velocity of the water but will also decrease the overall flow rate of the system. So it might help a bit with circulation at the expense of pump run time. It surprises me that the pressure doesn't increase by a little but it could be that the head loss in the rest of the return side is more significant so it is hard to notice.
 

Rangeball

Well-known member
May 25, 2007
785
I had expected a change as well but it may be and I'm not seeing it do to what you said above about gauges not being as accurate at low readings.

I'm currently running the pump 24/7 on low, so I may try it and see. I should be getting a bit over 2 turnovers a day based on calculations, and so far the pool looks great.
 
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