Hi:

As you can see I am in the solar hot water biz in Mexico.  I have been spoiled since we are in the tropics and can build direct open loop systems that are PV pumped with flat-plate collectors.  However, I have no experience with heat exchangers.  I am building a 650 gallon in-ground spa and would like to heat it with a "beefed-up" solar domestic system where I will circulate the excess hot water from the solar storage tank through the heat exchanger to heat the spa water being circulated by a 3/4" HP filter pump and will have a salt purification system.

A few questions for you:

1.  Using the SP 155K HE that you sell, do you think 1/2" copper pipe (insulated) would be sufficient for my heating loop from tank to the HE?  Or should I use 3/4".  (I use 1/2" for my solar loops and all of my HT insulation that I have had to ship and import is for 1/2"; so I am hoping 1/2" will do).

2.  I have to pay 33% over my invoice amount for items that I have shipped and imported into Mexico.  Can you give me a dealer discount on a HE and maybe a circ pump for the heating loop to the HE to help offset this?  You would only have to ship it to my forwarder in San Diego.

3.  Any other advice or recommendation on this?

The domestic SHWS is already in place and I am breaking ground on the spa next week; so your prompt feedback will be much appreciated.

Have a good day!  Skip