Note:  These steps are designed for WBP Controllers manufactured in 2016 or later.  Ensure that the driver board has the separated connectors that step 4 shows before you cut any wires in step 5.   

1. Disconnect chambers and calibrator from the controller, then power it down and unplug power.
2. Open the lid by unscrewing the 11 screws around the top (3 per short side and 5 on the long side in the back).
1. You may have to use a flathead screwdriver to help pry the lid off once the screws are out.
    
   
   
3. Locate the valve that you want to replace just inside the site you want to fix (in this example, Site 1).
   
   Note: If your valves or connectors have numbers written on them (the below screenshot says “3”), these numbers do not correlate with the site numbers.
   
   
   
   
4. Locate the connector from the valve to the driver board on the back-right side of the Controller..
   
   Note: these are in opposite order from the valve locations: the connector for Site 1 is the furthest to the right whereas Site 4 connects to the leftmost spot.
   
   
   
   Note:  If your driver board does not look like the above picture, it is an older model that the following steps will not work on.  Contact Technical Support.
   
   
5. Now that you know which valve will be replaced and where the new one will connect, you can cut the wire to the old valve.
   
   
   
   
6. Unplug the connector you located earlier from the driver board, and pull the entire length of wire through the wire bundle until the cut end is out.
   
   
   
   
7. Using a Philip’s head screwdriver, remove the two screws securing the valve to the acrylic manifold.
   1. Note: Be cautious when handling the screws—they can be difficult to retrieve if they fall inside the unit.
      
      
      
      
8. Once the screws are removed…
   
   
   
   
9. Lift off the valve. Ensure that the two black O-rings remain in their proper location on the manifold; they may stick to the bottom of the valve as you remove it, but be sure to place them back properly.
   
   
   
   
10. Put the replacement valve (p/n 601-4002-001) in the same location, taking care that the O-rings stay in place, and screwing them back in with the same screws
    1. Note: You will want to make sure the valve is screwed in tightly, however do not overtighten it or else the O-rings may flatten and restrict the opening which could cause a calibration error. 
11. Connect the other end of the wire into the same location on the driver board where the original valve was connected (in steps 3 and 5).
    1. Note: You do not have to bundle the wires together—that is simply to keep the inside tidy, but is not necessary from a functionality standpoint.  Simply have any excess wire length coiled inside the unit.
12. Replace the lid and plug everything back in.