I own a 2-story house with a hot water recirculation line. Two of the faucets consistently run out of hot water. I changed the internals in one of the faucets, to no avail. The faulty faucets will supply hot water at times, and then a flow slightly warmer, then cold, then a little hot again. I tried shutting off the pump for a few days, also to no effect. To replace the pump would be a problem, and I'm not dying to do it considering the remaining 5-6 faucets work fine. Any suggestions?