I just went through this with my black tank drain valve. When I got the water bay entry cover up and out of the way I could see the manufacturer's label on the valves. I called the manufacturer with the model number and coach information, and about four days later a new valve was delivered. The firm is located at Hollister, CA.
Soon after I replaced the black tank drain valve, the gray tank valve started acting up. So yesterday I received another valve standing by until I get home late next week when I will change it out. These valves have an expected life of eight or so years. I suggest if you think your valves are near eight or thereabouts years old, then change them both. The hassle of going through that water bay entry cover is much more work than replacing the valves! Assuming mine were original, they have lasted for thirteen years. My model valves, including shipping, cost about $110 each.
My model: 5197-DM-10-MS - Drain Master Electric waste valve with magnetic indicator switch. Includes plugs for easy installation. Includes seals, nuts, bolts, lubricant and installation instructions.
Contact:
Cheryl Ann
Drain Master
(877) 787-8833
(831) 636-9775
www.drainmaster.comPlease tell Cheryl "Hello" for me. Nice lady!! Very helpful.