The a hot water circulating pump installed on my water heater is on a timer, set to come on in the early morning and early evening . It has worked great up until I had the water suppy shut off for a repair. Now I only seem to get hot water when the pump is circulating. If I call for hot water in the middle of the day the best I get is like warn.
It is possible that some sediment or debris (from when the water was off) is messing with the by-pass valve and thus not allowing for a free flow of hot water when the pump is not running?