You had to turn off your cold water supply for what purpose? Did you break open a pipeline or joint and allow air into the system?
Perhaps you would be so kind as to explain what exactly you did and why to get this result. Simply turning a valve on or off would not normally create any problem unless the jumper valve or seat in the valve stuck or jammed.
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians