Davegvg said:
PSI is completely variable depending on my pump speed and the solar tap being open or closed.
Calculating head based on pressure, nets a different head # at every pump speed.
Thats correct, plumbing head loss is dependent on flow rate so it will change with RPM as does filter PSI. The pump's head curve also changes with RPM.
Unfortunately, I am still not able to make sense out of your numbers. 28 PSI relates to ~68' of head loss and at 3100 RPM, the flow rate of the JEP 2.0 would be only 35 GPM not 70 GPM so the filter pressure must be high for some reason. To get 70 GPM, I would expect filter pressure to be around 24 PSI for 3100 RPM. Is the pump below the waterline and if so, by how much? Are you sure the filter gauge is working properly and goes to zero when the pump is off?
For now, we can assume the pump is putting out 70 GPM at 3100 RPM and with a 4 degree rise, that is 140k BTU/hr which is reasonable and about what I would expect from panels that size. The maximum output the panels could possibly produce is about 154k BTU/Hr without other losses/gains which would create a 5.4 degree delta. Unfortunately, this is still much less than the 313k BTU/Hr that you had estimated.
I checked Sunday in the area you mentioned and the weather was shown to be
this which is a little warmer than what I was assuming. The dew point was still quite low which means that evaporation should have been fairly high during the day. So unfortunately, there still isn't any reason why you could have possibly gotten a 15 degree rise in a single day. The most I can come up with is 1.2M BTU/Day for the panels and 341k BTU/Day for the pool so a total of 1.5M BTU/Day which should have raise the pool temperature by about 9 degrees. BTW, that is about the maximum I have seen out of my panels.
So bottom line is I still can't explain why you would get a 15 degree rise. It just doesn't seem possible.
