Electric valve control . . . with a twist

Snackchaser · Saturday at 07:31 AM

This modification improves electric valve control by adding a rotary switch to select the four different valve line-ups: Normal, Freshwater Drain, Boondocking, and Winterization. I was really inspired by JD1923 and C&M Currie who replaced their quarter-turn valves with electric valves so they didn’t have to lift the bed mattress to change valve positions. This is a fairly extensive modification because the heater vents had to be removed for access to the valves, the new electric valves had to be installed, a recessed enclosure was needed to protect the switch, and number of new wires had to be run

Four of the original quarter-turn valves were replaced with two 3-way electric ball valves in the orientation shown in the photo. I used 3/4” valves with 1/2” adapters and SharkTooth PEX fittings for better flow. A little heat helped to slightly bend the PEX pipe into position, and the valves were clamped down with 1” electrical PVC clamps. A 1/2” electric ball valve was used for the freshwater tank drain. There was limited room to work in this area so it helped to pull out the PEX drain pipe where it penetrates the floor.

The switch was mounted on the forward facing wall of the outdoor garage where it’s more convenient to conduct the valve operations. To keep it out of harms way, I made a recessed mounting plate out of 1/8” hobby plywood and moulding stock as shown on the drawing. The plywood can be cut with a razor knife if needed.

The following legend helps explain how the rotary switch is configured. It shows the original five quarter-turn valves and the replacement motor operated valves. It also shows the four switch positions as they correlate to the valve line-ups, and the wire terminals used per the wiring diagram.

			Original Oliver Valves
			1	2	3	4	Drain
			New Valve Identification
Switch Position	Switch Terminals	Valve Line-up	A (3-way valve)		B (3-way valve)		Drain
0	None	Normal*	Open	Closed	Closed	Open	Closed
1	1-2 3-4**	Freshwater Drain	Open	Closed	Closed	Open	Open
2	5-6 7-8*	Boondocking	Closed	Open	Open	Closed	Closed
3	9-10 11-12**	Winterizing	Closed	Open	Closed	Open	Closed

* Valves in the de-energized position

** Terminals used for optional LED indicators

*** Terminal-8 is Jumpered to Terminal-10

The rotary switch needs jumper wires that can be pre-wired on the bench using ring terminals. This will keep them in place while connecting the field wiring using the included forked terminals. The valves use very little current so the +12Vdc can be picked from any convenient power source and protected with a 5 amp fuse, I used a nearby breaker. An internal capacitor powers the valves back to the “Normal “ position when de-energized (Position-0.)

Five wires were encased in 3/8” split sheathing and routed under the floor to the valves. This included three power wires for the valves, one ground wire daisy-chained to each valve, and one spare wire for an optional pump LED that I’ll cover in a different post. I also added an optional 1/8” plywood label board with LEDs to indicate which valve line-up is selected. I printed out a switch label, had it laminated, and glued it on piece of 1/8” plywood with holes drilled for the LED’s.