Are you sure it's the pump? The fan on this boiler will come on occasionally for 30 seconds to get rid of the heat from the pilot light. If the noise is only coming from the boiler it's unlikely to be the pump as that is not fitted within this boiler.
Are you sure there is power to the receiver? Take it nothing happens when you press the buttons on it? From the wiring you describe it looks like you have a combi boiler?