Turn off electric and gas supplies
Isolate heating circuit - two valves on 22mm pipes left and right underneath boiler - quarter turn on screw.
Drain boiler by opeing the drain vents on the same valves.
Now you can replace diverter valve
Repressurise boiler to 1.5 bar
Open isolating vales
Check pressure again
Check for leaks
Restore gas and electric supplies
Run the boiler - check for leaks and correct pressure.
Isolate heating circuit - two valves on 22mm pipes left and right underneath boiler - quarter turn on screw.
Drain boiler by opeing the drain vents on the same valves.
Now you can replace diverter valve
Repressurise boiler to 1.5 bar
Open isolating vales
Check pressure again
Check for leaks
Restore gas and electric supplies
Run the boiler - check for leaks and correct pressure.
