Loading... Please wait...The ENVIROSTAT FP4iL is a electronic thermostats designed to give energy-efficient frost protection to pipe work where thermal insulation alone cannot protect pipes from freezing or being damaged by ice. The FP4iL has a built in feature were every 7 days the temperature with rise to 55°C for a period of 4 hours before returning to its original level. The units control heater tape or Infra-Red (IR) quartz lamps.