Function selector guide

Please note that the function selector must not be lubricated on site – it requires a special lubrication
Function selector FFF-version

Most damages to function selectors are caused by back-flow of chemicals or water – this can be caused by:


1. Defect non-return valve(s) for chemical

Check non-return valve by dismounting the suction hose on the needle valve. If water appears the non-return valve is defect (water inlet to the unit must be open).
Change non-return valve.

Non-return valve with Viton o-rings: 20-200111 // With EPDM o-rings: 20-000110

2. Defect chemical valve(s)

Chemical valve 20-000830: Change the valve
Chemical valve 20-000810 and 20-000800: Control valve by disassembling the valve and check if o-rings and cone point are damaged. If yes, spare kit is available: Viton o-ring: 20-000811, EPDM o-ring: 20-000801. If no, replace by 20-000830

To prevent failure of the chemical valve and non-return valve, make sure to flush the injector system with water after using chemicals.


Exchanging function selector

When exchanging the function selector, please note:

  1. Control the function of the non-return valve(s) and the chemical valve(s). Replace if necessary.
  2. Air hoses between function selector and chemical valve must be flushed with clean water or replaced by new.