Appendix B: Decoder Types

Modified on Fri, 23 Jul, 2021 at 5:19 PM

The factory default for your TWC NV is to allow you to choose between just two built-in decoder types. These decoders have a fixed switch code of 59F350 and allow for one or two attached valves, respectively.

If your needs are more advanced, you can define up to five different decoder types manually and use these when configuring decoders as described in Section 4.1, “Configuring field decoders” [page 19] of the TWC NV User Manual.


  1. First you must set switch number 10 to "Closed" as described in Appendix D, Changing DIP switch settings [page 77].
  2. Now turn the mode selector to SETUP mode.
  3. If your DIP switch settings were correct, you should see a menu item called 1. Valve Types. Press the ENTER button.
  4. Select one of the five decoder types and press the ENTER button.
  5. Push the ENTER button to activate the switch code field for editing, set the switch code with the item selectors and push ENTER to save.
  6. Move to the No. of valves column, activate it by pushing the ENTER button, set the number of valves this decoder must be able to open (1-10) and push ENTER to save. This is the number that the controller will use to keep track of how many valves are open in the system.
  7. Move to the OK field and push ENTER to save the decoder and return to the Installation menu.
  8. Repeat from step four from all the decoder types you wish to configure.
  9. Now your custom decoder types will be selectable when entering decoders as described in Section 4.1, “Configuring field decoders” [page 19].



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