I have a 2004 Winnebago Adventurer 33v with a Atwood 10gal hot water tank,2 weeks ago while out camping we had no water coming out of any of the faucets on the hot side,After some research I determined it was a check valve that went bad.when I went to replace the check valve it looked like there were 2 check valves on the back of the heater. One right after the other. I took it with me to the RV place and they said one must have gone bad and someone just put another one right after it.So I only replaced one the other one you could see right thru it.I go camping this weekend and I got water coming out all faucets but all cold water.My hot water heater is full and when I open the relief valve its very hot water coming out it.My question is do I need 2 check valves on my water heater.I even tried the bypass valve to and still cold water coming out. Thanks Ron