Noise from water pump and low water pressure

[jerrymcg]

I have a waterpump in my house that makes a short sharp revving noise when I turn off certain hot water taps. This only happens when the timer for heating the hot water is off. The water pressure on these taps is good. Is the noise from the pump normal?

In addition to this the bath hot tap has very low water pressure and when I turn this tap off I get no noise from the water pump. Is the low pressure linked to the lack of action from the water pump?

Any answers or advice would be greatly appreciated.

Jerry