Watts R4X40-3 - Manual (Page 14)

V. MEMBRANE REPLACEMENT
1. Turn off the system and close the feed water shutoff valve.
2. Unplug the unit.
3. Disconnect the tubing from the top of the membrane housing(s).
4. Loosen the clamps and remove the top end cap(s).
5. Remove the old membrane(s) by pulling them up and out of the housings. You may
need to grab the old by the membrane with a pair of pliers.
6. Install the new membrane(s) in the housing(s) and replace the end caps. The new
membranes should be installed in the same orientation as the old membranes.
Note: It is very important that the brine seal does not flip up or roll when installing
the membrane brine seal first. Use plenty of glycerin lubricant and use a gentle
twisting / rocking motion as you slide the membrane in. If you are unable to install
the membrane brine seal first without rolling the seal then lay the unit over, remove
the bottom end cap, and install the membrane brine seal last.
7. Reconnect the tubing to the bottom of the membrane housing(s).
8. Follow the start up procedure in section III-D.