Pool and Pump

[jjackson07]

I have a 13 year old Viking Pools fiberglass Cape Coral pool which is 10' x 20' and holds 3,750 gallons. It is currently pumped by a 1 1/2hp Hayward Super II Pump and filtered by a 175sqft Hayward Star-Clear Filter. In Summer 2012 I installed a homemade four panel solar pool heater and connected it to the pool system. The four panels are coil panels made from 1/2" poly tubing and connected together by 1/2" poly tubing as well, and supplied by 2" pipes from the filter and returned to the pool via the pool's return line which is also 2" pipes. The solar heater sits on a wood frame approximately 7 feet above the ground on the side of my house where my pool and spa filters and pumps are located.

Currently my water pressure dies when I switch to the solar heater. I have three valves (supply, return and bypass) that will let me switch the flow through the solar heater only, bypass the solar heater and go directly to the pool, or flow the water through the solar heater and directly to the pool by opening the bypass valve 1/4 way. It will only maintain pressure when I don't flow the water through the solar heater or I open the bypass valve 1/4 way. So, I believe I'm going to have to buy a new pump, and while I'm at it switch to a sand filter. I'm thinking about updating to variable speed models to meet California's pool laws on variable speed filters and pumps, and I was wondering is the TriStar 2-Speed EE Pump compatible with the Pro Series Plus Side Mount Sand Filter S311SXV? And, will they give me enough pressure to flow the water through my solar heater when I have the valves set to let the flow go through the solar heater only?

[TSH Tech]

Let me answer the new products portion of your questions;
Yes, the pump and filter you mentioned will work together, however you are going to need to add a new digital timer for a 2 speed pump. If you have the old 'dial' type timer, a 2 speed pump will not work due to the wiring limitations. You will need to buy the Intermatic P1353ME digital timer, which includes the instruction guide for wiring up the 2 speed motor in order to utilize the 2 speeds. So your shopping list will look like this:
-Pro Series Sand Filter S311SXV?
-TriStar 2-Speed EE Pump
-Intermatic P1353ME

If you are unsure about wiring up a new timer with a new pump, perhaps I could suggest a Waterway Econoflo VSA pool pump, which is a variable speed pump that includes a built-in digital timer that is extremely easy to program.

The Tristar 2-speed will work with your solars, it puts out 2hp max at high speed. So will the Waterway. When running a solar heater with a variable or 2-speed pump, it is best to run the pump for 1 hour at high speed through the solars in the morning, then let the pump kick down into slow speed the rest of the day . I have the most difficult time trying to explain the dynamics with pool owners because they have that Tim The Tool Man mentality that bigger is better, faster and more power is better. Not so. The purpose of running the high speed first through the solars is to start the prime circulation of water going up then down through the plumbing. By kicking it down into low speed, the water will flow at a slower rate, saving you money AND, heating up your water at a higher efficiency. Why is this? The slower water passing through the solars has time to heat up much more hotter than at high speed, shortening the time it takes to heat the pool to the desired temperature while saving money on the electric meter. I don't know why this doesn't sink in to most pool owners.

~~
Second part of your question, the loss of pressure when your turn your solars on. This is clearly a hands-on trouble shooting type of problem. There's a variety of items that could cause this, broken filter, blown valve seal or broken valve, faulty gauge, etc.. Usually filter pressures go slightly higher when the solars are turned on, but you state the pressure goes down. That is a difficult to troubleshoot over the internet and there is no slam dunk solution to this particular pressure problem I could advise. I will advise this, after replacing your pump and filter and you still get low pressure, the problem is definitely in the valves or solars, because you've just eliminated the pump and filter issue.
Hope this helps!

[jjackson07]

Yes, it helps very much. Thank you.

[mas985]

The slower water passing through the solars has time to heat up much more hotter than at high speed, shortening the time it takes to heat the pool to the desired temperature while saving money on the electric meter. I don't know why this doesn't sink in to most pool owners.

Maybe because you have part of this backwards.

Solar panel heat transfer efficiency DECREASES with decreasing flow rate and increases with increasing flow rate. When the flow rate decreases, the temperature of the water in the panels increases and since heat loss/gain is proportional to the temperature difference of the panels and the surroundings (e.g. sky temp, air, roof, etc), the higher the panel temperature the more heat is lost to the environment and less heat is gained. The highest heat transfer will occur at the highest flow rates although there are diminishing returns. Most manufactures recommend 0.1 GPM/sq-ft to achieve the best results. Below that and the efficiency starts to drop off.


Some references:

http://www.builditsolar.com/References/ColFlowRate.htm

Basically, flow rates that are too low will not remove the heat efficiently from the collector, and the efficiency of the system will be low.

http://www.sunsolar.ca/images/SunSaver_Specs.pdf

viewtopic.php?p=28336

http://www.troublefreepool.com/sweet-sp ... 30057.html

Not only that but for most solar systems with a VRV on a two story roof, it isn't possible to run on low speed. The VRV will open losing prime.

[jjackson07]

Hi I just wanted to give you an update.

I've installed my new pump and filter and they work like a charm with my solar pool heater!! The water is flowing way better than before on high and low speeds. I bought the Hayward TriStar 1HP 2-Speed EE Pump (SP32102EE), and I bought the Hayward Swim Clear 325 sq. ft. Cartridge Filter (C3030) instead of the Pro Series Sand Filter (S311SXV) because I didn't want to have to deal with all the backwashing. I also bought and had no problem wiring up the Intermatic 3-Circuit Digital Time Clock (P1353ME) with the new pump. Programming it was easy, as well.

I am going to try your suggestion of running the pump for 1 hour at high speed through the solars then let the pump kick down into low speed the rest of the day.

I bought a Barracuda G3 Suction Side Cleaner, as well, to replace my non-working Hayward Navigator, and it works great with the new pump. And, during that first hour when the pump is on high speed, I will be cleaning the bottom of the pool. I may run the pump on high speed again at the end of the day for another hour to do another cleaning if necessary.

Thank you!