My heated floors began tripping the GFCI and I was afraid there was a short which would have been difficult and expensive to track down. Fortunately, after contacting Warm Your Floors, I was told that it was more than likely a failure of the control unit itself since the units only have a lifespan of five to seven years or so. Why that is I don't know, but I ordered a new unit and got conplete information on the proper replacement procedures and my problem was solved. Warm floors again! The product was shipped out immediately and the customer service was excellant.