Shortly after I bought my five yr. old house, I tried to drain the sediment from my electric water heater. I was unable to open the drain valve by hand so I tried using a pair of water pump pliers. The knob is made of nylon so I didn't want to break it off or strip it so I gave up trying to open it. The valve is located very close to the floor of my garage so that I'm just barely able to screw a water hose onto it. How do I get the drain valve opened without breaking it?