How do I replace the ASOV?

If you have to remove the ASOV for some reason, here is how it should be reconnected:

Even more detailed:

The ASOV (the white thing with four fittings) is marked clearly with IN and OUT on the side opposite where the screws are located. Please look closely at the pictures above to avoid hooking it up backwards. Mark the tubing prior to disassembly to avoid mixing up the lines.  The ASOV needs to be installed the same way the old one was, with the four screws facing the same direction. Take a picture with your cellphone for a reference point.

It is very important that the flow restrictor not be lost. Read more in the next sub-section.