I'm re-doing the solar on my system, and it's brought up to me the issues I have with my pumping. Here's an overview:
Intelliflo VF 3 Horsepower Pump
2 Intake pipes (One spa drain, and one pool skimmer, usually set to 100% pool)
2 Outflow pipes (One into 4 jets on the spa, and one into two jets in the main pool, usually set 50% pool/50% spa)
Both the Intake and Outflow pipe pairs go into Jandy 3-way valves into single pipes into the pump and outflow equipment.
All pipes appear to be 2".
After the pump I have a 60 sq-ft DE filter, a 8-panel Solar Heating system on my roof, and a 400k BTU Gas Heater (rarely used, and plumbed around when not used)
The pool has a suction crawler and debris bag attached at the skimmer, which takes nearly all of the flow through a speed control valve, and which blocks most of the skimmer action. In the winter, I aim to run the system at 15-20 GPM for the crawler. In the summer, I open the speed control valve appropriately and run at 32GPM (for the solar).
When I tested the system earlier this year, I reached a maximum flow of 40GPM with the pump running full out at 3450rpm and 1945 watts. Is that reasonable for a system of this sort? The solar panels recommend 4 gpm per panel. With 8 panels, that requires 32GPM, 2750rpm and 1000 watts. 10 panels would require 40GPM and a pump running full-out to optimize their heating.
Is this a reasonable flow/power/speed rate for the system as described?
I see graphs and other pools reporting flow rates in the 80-100GPM range. This system can't get anywhere near that. Why? What part of the setup is causing the lower GPM I'm seeing?
I'd enjoy having the two additional panels, but not with a doubling of power required. Why does it take so much more power to get those last 8GPM?
Are there other steps I should consider taking to improve the efficiency of the system?
I always have air in the system outflow at startup. My assumption was that that was from the solar system vacuum breaker valve. Is that correct? Do I need to keep anything in mind regarding that?
The DE pressure gauge is hard to read, given the changing flow. At full-flow for summer, it usually starts at about 20PSI, and I backwash at about 30PSI. Is that right?