[Motor31]

You do know that without the check valve function, your water heater is trying to heat the water in the inflow lines as well as what is in the heater. It makes the water system in your rig a giant heat sink and will cause the water heater to operate far more frequently as the water in the line bleeds off heat into the lines.

Rather than just leaving it an open line is it possible to put a second check valve in line with the original so you do not have to remove the now non functioning valve? You may have to get a plumbing nipple for the connection to allow them to fit together then replace the inflow line just a bit farther back.