We are buying a house and had the pleasure of doing the home inspection today to find that there is something very strange going on with the hot water circuit to some of the bathrooms. The best example is a jack and jill style bathroom that has a shared bathtub and then two separate sinks. One of the sinks has very hot water and the other has luke warm water that seems to fluctuate warm to cold. They are 10 feet apart and the hot water valve are not mixing valves, they are individual from the colds.
Also the master bathroom has the same luke warm water that the temperature fluctuates. This house has a recirculating pump with the check valves installed.
I have never had a recirculating "instant hot water" system and wondered how I can troubleshoot this problem. The house sat empty for several months. Any help is much appreciated, the house is five years old and do not believe that there is a cross over issue because the previous occupants said the hot water worked fine a couple of months ago.