Hey I have bought a pressure switch on fitting pipe is too big to connect its the dark solid blue pipe anyone know a n adapter which will fit one end will need to be small to fit pressure switch and other end biggerto fit blue pipe sorry hope this makes sense
You need push-fit connectors, one either side of the pressure switch. One end of the connector pushes onto the pressure switch and the other end pushes into the 12mm. diameter blue pipe and exactly the same the other side.
If it's proper food grade water pipe (which it should be) then it will be metric and not imperial. However, you can always use 1/2 inch jubilee clips to connect the water pipes instead but make sure the connections are tight and check for water leaks once the water system is pressurised.
If the water pipe turns out to be is 1/2 inch diameter (12.7mm.) then the pipe it will easily slide over the spigot on the pressure switch.