FPTFROST PROTECTION THERMOSTAT FPT

The FPT range of thermostats provide a low cost switch output based on the average temperature detected along a 5 meter capillary sensor.

The most common application is for frost protection on fresh air intakes or air-conditioning systems, to prevent the icing up of filters, fans and coils. The capillary is fixed in a matrix across the duct, in a position downstream of the pre-heater or frost coil.

The FPT thermostats are used for regulating, monitoring and alarm systems in industry. FPT thermostats are temperature-operated electric circuit breakers. The thermostats are fitted with a single-pole switch (SPDT). The position of the switch depends on the thermos- tat setting and sensor temperature. The FPT thermostat can be connected and switch to single-phase alternating current motors of up to about 2 kW.

FPT frost protection thermostats sense temperature by means of a thermal system, consisting of temperature charge, bulb, capillary and bellows. The temperature charge changes its pressure based on the refrigerant tempera- ture to be sensed. The sensor is the portion of the system which is in thermal contact with the refrigerant, the capillary connects the sensor with the bellows and the bellows contracts or expands depending on the pressure, causing the thermostat to operate the electrical contacts. An exception are capillary type of sensors, which do not have a bulb, instead, their capillary serves as the bulb directly. Charges and sensor types are matched to temperature ranges and other application specific characteristics.