In the process of building a steel walled vinyl liner the pool.
Pool will have a waterfall with an expected flow rate of 150 gpm.
PB has installed two 1.5" threaded fittings to accept the Waterways 6" Ultra Suction Equalizer.
The Waterways 6" Ultra suction equalizer can fit 2" and 2.5" threaded fittings, but the PB (I searched also) could not find the larger fittings.
The fittings go almost immediately to 3" pipe. The 3" is then teed together to satisfy VGB.
The return (waterfall source) is 3" pipe.
The pump is to be a 2HP WhisperFlo pump.
The PB has the suction lines space to comply with VGB.
I'm concerned about the water velocity at the equalizer cover.
VGB states that it should no exceed 6 ft/sec within 3 feet of the suction port.
Looking at some flow charts, in order to get 75 gpm (2 suction ports yields 150 gpm) through a 1.5" opening would require a velocity of 11.8 ft/sec at the fitting.
I found some info on the suction cover at http://poolspanews.com/products/2011/07index.html
The 6" Ultra Suction is perfect to use for retrofitting and can be used with the following flow rates:
191 GPM @ 6.02 ft/sec (for 2" Equalizer and 2.5" Threaded),
136 GPM @ 4.30 ft/sec (for 2" Threaded and 2" Insider),
and 77 GPM @ 2.43 ft/sec (for 1.5" Threaded and 1.5" Insider).
I'm trying to figure out these numbers for the 1.5" threaded.
Why is the flow given at 2.43 ft/sec? Is this saying that the cover acts as sort of a suction diffuser, thus enabling a 77 GPM flow rate with only a 2.43 ft/sec water velocity at the point of suction for a 1.5" threaded pipe?
If this is the case...then we are good to go.
Finally, does the 1.5" return fitting introduce any significant head loss?
I found head loss figures for (per 100'). What about for just a 1.5" suction port?
Thanks for you help.