Well I primed the system again with the hot water and cold water taps open.I have a feeling I didn't have the hot water tap open last time.i wonder if pressure built up and there is some release valve or something on the bottom of the hot water heater.I'll keep an eye on it.I was also getting some leaking from the drain valves under the sink and this seems to have stopped as well.Has anyone experienced problems with the in line drain valves leaking?