FAQ Search Select a Category BarkBath Cleaning Formulas Cleaning Tips Commercial Products Corporate Deep Cleaners Hard Floor Cleaners Mops, Brooms and Brushes Parts and Accessories Steam Sweepers Vacuums Warranty Web Site and/or go Little Green® 1720 Series Heater Information Answer: The heater needs about 30 seconds to warm up before the light will turn on. The light will stay on as long as the heater is up to temperature, whether the power is turned on or off. Any water left in the hose from testing or prior use will start out cold. It may take one minute to allow any fluid left in the hose from previous use to travel through the upholstery hose. The heater will increase the water temperature up to 25 degrees warmer then the water in the solution tank.