it is leaking from underneath the diverter valve motor, the part is called a 3 way valve cartridge, i have got a part number of 720003100 but could not find one so i phoned baxi tech department and was told they only do a cartridge for the one without the bypass pipe, the boiler is only 3 years old so do i have to replace the 3 way valve completely or can i put new seals on this cartridge