If I have a Grundfos Circulating Pump installed to use with a gas water heater, is a timer needed on the water heater, or are timers used only with electric water heaters? I need to have access to hot water at all times of the day for the areas served by the circulating line so the water needs to be hot all the time. Thanks for any advice including important information in reference to the circulating pump itself...Is there one model that's better than another by Grundfos? There are 11 fixtures plus a washing machine that will be served by the hot water, but 7 of the fixtures are seldom, if ever, used.