It would help to have the name of the manufacturer, model number for sure and you can locate an owners manual very easy. My input is this. I have an identical hot water heater just like the one Alan has shown in this thread. My heater did not have a drain valve on it. Mine had a round plastic like plug with a metal cover and threads for a very small square headed screw. I contacted Seaward with my delimia, and was told it should have had a valve on it and did not know what the plug was in my heater. Even checked with their Engineering department, no ideas. They did however send me a drain valve at no charge. In previous years I disconnected the water line after the pump, before the heater inlet valve, and with all the outlets open, I use an air compressor and push the water out of the entire system. I was very lucky one day picking up parts for my auto repair business and found a very small threaded on/off valve that just happened to fit the threads in my hot water heater. Alas, now I can drain it into the bildge with a hose attachment. Hope this helps. Someone on this web site will have the answer you are looking for. Good luck.
