We have had this house about a year. Water has worked without a hitch, until about 2 months ago. The spare bedroom, which is used very seldom, no longer has hot water coming out of the sink or shower/bath. Cold works fantastic, but neither sink or shower faucet or showerhead work on hot. It obviously isn't a faucet or showerhead problem. Please help!! (oh, and water heater is only 2 yrs old)