I sent them an email. I'll post if I hear back. Thanks!

I was considering the Marathon but was warned about exceeding the max temps per the warranty if I connected it to solar thermal panels. I plan on using the Lochinvar Sun Saver Solar instead. It only has 2 inches of foam insulation versus 3 on the Marathon but can take many times the temperature of the marathon unit.

Posted By Torben on 10 Feb 2010 10:23 PM
I was considering the Marathon but was warned about exceeding the max temps per the warranty if I connected it to solar thermal panels. I plan on using the Lochinvar Sun Saver Solar instead. It only has 2 inches of foam insulation versus 3 on the Marathon but can take many times the temperature of the marathon unit.

Are you not using a recirculating pump with your SHW?  Are you wanting to boil water?

Marathon gives their warnings about solar hot water systems ability to exceed the allowed temp of their tanks here:

http://www.marathonheaters.com/cont_solarapps.html

The lochinvar has glass lined tanks (fused at 1600 degrees).  The marathon is definitely a better tank if you are sure you will never exceed the allowed temperature.  I'm not positive I'll never exceed that temp (boiling is 212 at atmospherice pressure, it is higher when under pressure).  I'll use a recirculation pump


I'll probably use a direct ciculation system but could use a thermosiphon system since freezing shouldn't be a problem.  Most of my plumbing will be PEX with a central manifold.  The plumbing in and out of the water tank and running to the solar panel will be thickwall copper.  I will put a thermostatic mixing valve on the hot water supply from the tank so that no matter how hot the tank gets the water in the house can be kept at a safe temperature.  If the tank is significantly hotter than the valve setting this increases the effective size of may hot water tank.  I plan to buy an 85 gallon since the next size up is a significant uptick in price.  The electric heating element will be set on a low setting and should not come on very often once the solar system is installed.

This is a link to the sun saver solar

http://www.lochinvar.com/products/Default.aspx?type=ProductLine&lineid=51

I'm curious to hear what you choose and how you set it up since Marathon was the other one I was considering.