Solar plumbing - Do I need a second path to isolate the solar?

[jimmyfloyd]

I am working on Plumbing my solar panels and have a question about necessity. THe majority of the diagrams I see have the 3 way valve as the only path for the water exiting the pump/filter. THe value therefore needs to be used to manage which direction the water goes.
For example:

http://www.solarindustries.com/images/schematic.png

Now, I did se one diagram where there is a bypass section using 3 valves so that you can completely bypass the solar, or use it to limit the amount of water going to each. Example from Hot Sun Solar Pool Heating l How Does a Solar Pool Heater Function?:

Is this bypass loop necessary? I am in Upstate NY, so the pool is only open 4-5 months out of the year, and closed otherwise. If it is not needed, that makes the plumbing much simpler.

 

[mas985]

You don't "need" the bypass because the solar valve can act as a bypass too if needed. It just isn't as convenient as a separate bypass.

 

[jimmyfloyd]

You don't "need" the bypass because the solar valve can act as a bypass too if needed. It just isn't as convenient as a separate bypass.

So would you recommend putting one in? Since I am still planning, I have the option to, however it would add some additional turns into my plumbing given the space I have.

 

[mas985]

I do not have one in my system but I have a VS pump so I control the flow with that. With a single speed pump, there might be some value having one but again, bypass can be accomplished with the solar valve too.

 

[jimmyfloyd]

Finally finished plumbing this up and did go with the bypass. While not completely necessary, since our pump is only a 3/4 hp, I liked the piece of mind in case we upgraded. Next is to figure out how to add the Hayward Solar Controller into the mix.