Old & RVer's- I believe both of you have extra solenoid valves. Toward the end at least, WRV was ordering 4-wide solenoid manifolds only to save on stocking multiple manifolds, and then wiring up as many solenoid valves as needed for the coach under construction. A 4-slide coach w/4 SmartBeds takes 8 solenoids for extend/retract of slides and 8 more for E/R of beds, total of 16. On my rig (only 2 slides, but 4 beds, need 12 solenoids) I had 8 solenoids on front manifold and 2 are not wired to anything. One of the 2 started to leak, so I called HWH for a plug to replace it (don't need an expensive solenoid valve just to fill the hole) and they don't make one; they only sell solenoids to fill holes on the manifold. There is another manifold on ceiling of basement; I believe (haven't checked mine yet) w/4 solenoid pairs. A 2 slide + 4 bed coach uses 12 total solenoids, 3 slide + 4 bed coach needs only 14 solenoids, a 4 slide + 4 bed coach uses all 16. If you have less than a 4-slide/4-bed coach, any extra solenoids can be replaced w/a plug. To check if you have extras, follow the wires out the back of each solenoid valve to see if the plug connector is connected to a mating wire harness; if not, Voila! you have a spare pair waiting to be (I hypothesize- begging to be) liberated and then used.
I had a machine shop use a valve end to make a plug conforming to the HWH thread/O-ring setup, and that is now installed on my manifold in the previously leaking but unused valve position. BooYah! No leak. Installs w/a 1" socket & extension after taking out the unconnected solenoid.
So if you want a plug to liberate your spare solenoid valves, I am having the machine shop make some extras. PM me for the cost & details.
Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project