My husband replaced our taps in the shower with new ones. We have grafity feed for the hot water and an inground water tank with a pump for the cold water. After he finished changing the taps I used the shower and it worked ok then the next morning the hot water tap when turned on does not give any hot water at all. I think this is a similar problem to what you are having so I hope someone answers us both lol. Fortunately we have 2 showers so we can use the other one until we find out how to get hot water out of the other shower.
Jude
April 2010