You can buy them over the counter. Rothenburger freeze kits (or hire out a big electric one from Brandon Tool Hire like a Rothenburger or REMS). Can't remember if they come with a can of freeze spray but if they don't buy a can for each time you freeze a pipe (when i freeze pipes i'd rather use more than i need instead of causing a flood
). You don't want to risk the ice block inside the pipe from dislodging. When/if you do it, make sure you have everything you need at hand to work quick! Freeze the pipe about a metre away from where you're working to you can 'ease' the pipe around without moving the ice. The water in the pipe needs to be stationary when freezing (basically don't run taps unless you want to get wet). Get and change the iso-valves then you can concentrate on the pump. If you use the electric kits, make sure you keep the freezer going whilst you work on the pipes. Pour cold water over the freezing electrode thingys to create a ice seal every 10 or so minutes.
http://www.transtools.co.uk/store/pr...ezing-kit.html
http://www.transtools.co.uk/store/pr...ay-500gms.html
http://www.brandontoolhire.co.uk/dir...?idproduct=377
Chaz