Michael,
Your coach probably has Drain Master electric valves in it. I have the same problem with mine sometimes, the problem with mine is the way they Monaco mounted them horizontal flat a no no. I replaced one of mine a couple years ago, they still stick sometimes and have to manually open it a little. On mine there is no way to re-mount the valves so the topworks are up and don't fill with water and crap.
Drain Master, LLC
400 Park Center Dr. Suite 6
Hollister, CA 95023
Toll Free (877) RV STUFF
877-787-8833
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