I want it to turn on and off a small Laing re-circulation pump that will circulate DHW from my standard propane fired 40 gallon water heater through a flat plate heat exchanger. The twenty plate hx will be heated by water from my Tarm Solo Innova or storage. I am looking to purchase a thermal snap disc control that will turn on the Laing pump when the boiler or storage water coming into the flat plate is hot enough to heat the DHW; and like-wise shut it off if or when the water becomes too cool to heat the DHW. What set point temperatures do you think I should have on the snap disk? One, http://www.pexsupply.com/pex/control/search/~SEARCH_STRING=snap disc, I was looking at, has a cut-in temperature of 150 degrees and cut-off of 130 degrees. Should I be going higher or lower on either temp setting? One other question. Many of the snap discs are listed to turn on fans. Any issue using one of these for a small pump? Thanks in advance for any help.