Don Buelke
Because of the longer hot water piping, the cold water pressure will always be higher than the hot water when a faucet is opened. Therefore the cold water will enter the hot water pipe and overpower the hot water flow. There are other situations where the same thing happens, and they are usually harder to find than what you have. Your easiest solution is to always close at least one of the water faucets.: I have a wye fitting that opens both hot and cold taps to join at a common hose. If the taps are left open, even though the hose outlet it closed, I will only get lukewarm water at the other hot water taps in the building. In other words the cold water flows back into the hot water lines. Why is that?
