Solar Heater ?

[kevincad]

Shouldn't be any problem mounting it vertically. Turn your pool into a science project and have fun. Whatever you do please keep us posted. Real life information is always welcome.
Al

I'll do that. Albeit it may turn into an expensive experiment, as is my usual! I really only need to raise the temp 5 degrees, or at most 10 a few weeks. My pool is 13,500 gallons, and I think it wouldn't take to much solar power to do that, if those kits work half way decent.

[tphaggerty]

I'm sorry but Poconos is wrong about how solar on a roof top works. While it is true that the system is "closed" when it is running, so the actual effect on the pump is small, all modern roof top solar systems are "drain back" type. That is, when the system is OFF, the water in the panels is allowed to drain back into the pool (through the returns on the return side and through a small hole drilled in the valve on the pressure side. They used to make "non-sealing" valves, but now they just drill a hole in the valve ball.). The water does NOT stay in the system when it is not running, a vacuum breaker is installed near the top of the system to allow air into the system so the weight of the water doesn't collapse the panels. Thus, your pump DOES have to get the water up to the solar panels everytime it turns on. I researched this for months and months before going solar, every major manufacturer designs this way, although it is not always clear on their web sites.

For a 3 story roof, you may have to (or want to for efficiency) go to an auxiluary pump. My panels are about 24 feet above pool level and they work fine with a 2HP pump (I am investigating if I can go smaller). For your size pool and only wanting a 5 degree or so rise, you might consider one of the smaller systems that simply tie into your filter lines (these are "closed" as Poconos said). I have a friend that has a one 4x20 panel that he uses for just such a purpose, it is laid out on a rack right next to his pool.

[Poconos]

I'm sorry I didn't mention drainback valves BUT I would think their use would be dependent on the type of panel and elevation. The only panels I'm familiar with are flat mats and homebrew because I use both. Neither sensitive to vacuum. You still have to purge air or water vapor no matter how it gets in the system. I don't think I said anything wrong and in the area where I wasn't sure, I stated that.
Al

[tphaggerty]

No, the air gets purged as you run the system, there isn't any particular purging cycle that has to be done, the air is purged into the pool everytime the system turns on. Didn't mean to jump on you, but ground/pool level mats and homebrew systems are quite different from tacking big panels onto the roof and you did mention the part about purging and vacuum pressure in 2 different threads....

Although the website is a bit dramatic, www.powermat.com (not an endorsement, I did get a quote from him, but didn't get my system from there) has some really good diagrams on how these systems work. I think when it was originally put together, drain back systems were somewhat new. Now, if you go to any of the manufacturer's sites (Heliocol, FAFCo, SolarIndustries) they all show rooftop systems installed with vacuum breakers and valves that allow full system drain back. That is also the reason rooftop systems are installed at a slight angle across the roof, it allows for full drain back (especially crucial for parts of the country that freeze, like New York).

I am just trying to help others jump start their understanding of how roof top solar works. As I said, I did months of study and when I finally thought I understood how the systems were supposed to work, THEN I called contractors. It really helped me figure out the ones that understood the systems and those that were doing it as a sideline.

Just a minor example: because you want the pressure side to drain back, the actuator valve has to be either a special "non-sealing" type, or it has to have a small hole drilled in the valve ball by the installer (right in the instructions for the SolarIndustries system I finally had installed). They don't make the "non-sealing" valves anymore (or they aren't widely available), so it is up to the installer to drill that hole! (Remember, this is right in the instructions for the system from the manufacturer). At least one installer I spoke to had NO idea what I was talking about when I asked about this, ALL of the others knew all about it (needless to say, that one didn't get my business).

[Poconos]

Given the various types of solar heaters and the possible locations, possible plumbing configurations, pump sizes, and other equipment options, there are too many variables to make a 'one size fits all' statement. We both have made our comments. I have nothing more to contribute to this specific thread.
Al