Water flow at all HOT water faucets is very slow in my new Holiday Rambler Admiral XE. Flow is fine at all cold faucets. Worked fine last fall but now, after taking it out of winterize mode, the problem persists. It is a single valve bypass system. I suspect there is a check valve sticking somewhere? Is it possible that this check valve is an integral part of the WH bypass valve? If so, can the check valve be replace or must one buy the entire bypass valve? First time MH owner frustrated with all the problems encountered.