Quote Originally Posted by chem geek View Post
I suppose there is a lesson for others in all of this. If you have long runs of pipe, be it to your pool or for a solar installation or both, then encourage your pool builder to use the largest pipe (especially for the solar) to minimize friction losses. This will likely let you use a smaller pump motor and save on energy costs. Does that sound about right?

I think you could save a bunch with your existing plumbing. Small pipes are better suited to smaller pumps than large pumps. Unfortunately, you already have a small pump. To get smaller, you have to go with a 2 speed and run on low speed most of the time. Think Pentair has a 1/2 HP 2 speed which might work.

As for my situation, a replumbing to the solar (and maybe of part of the solar) may not be out of the question since the pipes don't go under any sort of hardscape -- they run under dirt near the property line. Changing the lines to the pool is out of the question, but that's not where a large pump is needed anyway. I'll see about getting an estimate and see if something can be done that would save enough money to pay for itself in a reasonable period of time. Cutting down to a 3/4-HP unit would probably save me about 30% of pump costs or about $350 per year. I suspect the new pump plus labor is going to make the payback time a bit long, but we'll see.

Agian, a large pump is not really required for your solar even with 2" pipes. I think it would be more cost effective to just reduce your flow rates with a 2 speed pump and save energy. Remeber that at low speed, the head loss (PSI) gets reduced by a factor of 4 so with solar you will have about 7 PSI and without solar about 4 PSI.

I'll also look at pump-replacement-only options such as a variable speed pump since that will help in the hotter part of the summer when the solar turns off because the pool is warm enough. That's probably a more economical option (more expensive pump, but maybe a lot less labor).

You can run at lower speed with solar (after priming) or without solar and save money.

Thanks again, salinda and Mark (mas985) for your helpful advice.

Richard
See comments above.