Power direct vent water heater blower will not shut off. Plenty of hot water. Gas water heater. 75 gallons. State select model pr6 75n rvt. The blower is integral to the unit. I could not find the exact model number on the web site and did not find the problem under the troubbl shooting guide. The blower runs continueously even after the gas valve is shut off. The water heater is a high efficiency condensing type.