I'm an hvacr contractor that installed a heat pump system in Massachusetts in an addition. The customer caused the system to ice up by setting the thermostat too cold. One of my techs installed a freeze protection thermostat to stop this from happening again. Now the customer is complaining he can't get the system to run any colder than 66 degrees f. I have explained to him about how the system is designed to go no lower than 70 degrees f. But this falls on deaf ears. So, I was wondering if anyone knew of any printed documentation that I could give to him that would explain it better.