These Freeze Protection Controls are designed to protect pool and spa equipment and plumbing against freeze damage. They turn the pump and heater ON when the outdoor temperature drops below the temperature set by the user-adjustable thermostat. Models without timer connect to a timing or switching device and they control operation of the equipment, as well as protect it against freeze damage. Models with timer provide both automation and protection for the equipment. The PF1103 Freeze Protection Control is self-contained in an indoor-outdoor, beige, rainproof enclosure and designed to be connected to a timing or switching device. Together, they control as well as protect the Pool/Spa equipment and plumbing against freeze damage. The Control, if wired according to instructions, turns ON the Filter Pump when the air temperature (where this Control is located) drops below the temperature set by the thermostat dial (between 32 ̊F and 45 ̊F).