my hot water heater 's pilot light is on, but burner cut off after 5 to 10 mins. then don't back on unless manually set up higher temperature, then out again. the pipe out of heater is hot,but turning on the hot water tape, it's still cold water and pressure is normal. Recently some renovation happened in the bathroom. I turned main water on and off a few times. also plugged all the bathroom taps.but didnot touch any of the pipe.Please help, thanks.