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Discussion Starter · #1 · (Edited)
There's a couple ways to fix these Delta Touch2O models, especially the black ones with a battery pack that has exposed batteries. Often times when faucet won't shut off or similar this is an issue with the rubber tip on the solenoid plunger. The video at the very bottom shows the insides of these valves in operation and the importance of that little pressure release hole. Repairing the plunger tip that seals this hole is what I discuss below. Sorry, I was limited to only 10 pics, click on them for larger view.

One repair method often mentioned in video's and tutorials suggests unplugging the battery pack and touching those terminals directly to the + and - terminals on the solenoid using reverse polarity. This sometimes works, but only resets the position of the plunger inside the solenoid. You should try this approach first because it's quick and easy:
1) Just unplug the cable at the batter pack. It's a black plastic box connector on the end of the battery pack. Unsnapping this connector leaves two contacts like those on a 9v battery.
2) Disconnect the two + and - terminals (wires clips) on the solenoid.
3) Briefly touch the terminals on the battery pack to the tabs on the solenoid, just a few times. Do NOT hold the connection. These are pulse solenoids, designed for a quick brief pulse of electricity.
4) Rotate the battery pack and touch the terminals again a few times, using the opposite polarity.
This resets the magnetic plunger into its correct position inside the solenoid. The magnets inside the plunger hold it in the correct position and this resets that position.
5) Reconnect the wires to the solenoid and battery pack. Try the sink several times. If this does not work then onto the "Plan B".

Take pictures at each step of disassembly, use them during reassembly.

1) Turn off the hot and cold water valves to the sink.
2) Disconnect the sensor wire clipped to the bottom of the faucet spout.
3) Unplug the wire on the side of the valve body. It's a black plug, looks like a headphone jack.
4) Unplug the orange sensor wire connected to the bottom of the faucet handle.
5) Disconnect the bottom hose by removing the blue clip first, then slide the hose down and out.
6) Disconnect the top hose that leads to the faucet handle by pulling out the metal clip first, slide down hose.
You can now remove the entire valve body with the battery pack attached.

1) Remove the + and - wires connected to the solenoid.
2) Now unclip the electronics case from the front side of the valve body.This will separate the case that holds the circuit board and wiring from the section that flows water. Set electronics case off to the side.
3) Remove the 3 screws holding down the solenoid. If one of the wire terminals is blocking access to a screw, gently rotate the white part of the solenoid. Just grab it by the top around the wire terminals and rotate.
4) Carefully remove the solenoid from the valve body. Remove the plunger and the spring inside and drop them in a cup of water until ready to clean them. Don't let it dry out until cleaned.
5) Remove the rubber/plastic diaphragm from the valve body. Tip the unit upside and try to tap it out. Do not pry on any rubber edges of the diaphragm. If needed, use tweezers to grab the center plastic collar of the diaphragm and lift out. Drop diaphragm in the cup of water until ready to clean.

This is your chance to get everything back to like new condition. Take your time.
Valve Body: Clean the big black plastic valve body using soapy water or a touch of CLR or other cleaner. Use a paintbrush or soft toothbrush. Clean everywhere the water flows, from one hose connection out the other. Use a Qtip or brush to clean that area where water flows around the diaphragm, the most important area. You will see a white filter screen deep inside the connector for the faucet hose. Try to clean this filter out, remove any debris using a toothpick.
Solenoid & Spring: Using qtips clean the hole that goes inside the solenoid and the area around that hole. This is plastic so don't use harsh chemicals. Making it really clean helps the plunger slides in and out easily. Clean the plunger spring of any calcium buildup.
Diaphragm: DO NOT use CLR or harsh chemicals on the rubber diaphragm. It has been immersed in water for years and the rubber will be delicate. The diaphragm is made of a flat rubber seal and a plastic support. They are bonded together, do not try to separate them. Use soapy water carefully. Get into the deep ridge around the perimeter on both sides. In the very center you will see a tiny pressure release hole. This tiny hole is the key to making everything work correctly. Make sure to clean it using a toothpick while also cleaning the deep pocket on other side of this hole. Your plastic might look dark brown. If cleaned correctly it should be off white as seen in the pics. When done, if you have a high quality product that restores rubber/vinyl, like those for a cars dashboard, apply this to the rubber on the diaphragm and let it soak it up. You want to restore some oils back into the rubber.

Plunger: The plunger tube contains 3 parts sealed inside, do not try to remove these parts. There is fixed magnet on one end and a movable magnet with a rubber tip on the other end. A tiny spring is between these two magnets. Around the middle of the plunger you will see two access holes the size of a pencil lead. Carefully clean the plunger making sure to rinse out the inside center area using the access holes. You are trying to clean out any calcium build-up inside the plunger. Use CLR if you are careful, try to keep it off the rubber tip. When done, use small amounts of air pressure if available to clean out the center of the plunger. When done cleaning, the magnet with the rubber tip should move freely. Test this by lightly shaking the plunger or pressing on the rubber tip end. Clean the plunger again as needed. This plunger is a critical part.


The one end of the plunger has a rubber tip. When energized, this plugs that tiny tiny pressure release hole in the center of the diaphragm. If you look very very closely, the rubber tip on your plunger will most likely have an indentation in the center from years of contact with that hole. This is the problem you need to fix. This rubber tipped piece rotates and moves from side to side so this indentation doesn't always line up with and seal the pressure release hole. This means the valve won't build up pressure behind the diaphragm, and the faucet will not work.

Using 600 or higher sandpaper, carefully sand the entire tip and remove enough rubber so there is no longer any sign of an indentation. Course grit sandpaper will leave scratches and also cause leakage. It must be sanded flat but first you need to push the cylinder outward so the rubber tip protrudes from the plunger. Use the fat end of a metal sewing pin, push it in at an angle into one of the access holes in the middle of the plunger. Be careful not to bend the tiny spring inside. Don NOT use a toothpick for this step, if it breaks off inside the plunger you are screwed. Using tape, wrap the pin to the plunger to hold the rubber tip out. Now carefully sand the end of the rubber tip making sure to keep if flat and even. Use circular motions. This will take a bit of time - its hard to protrude the rubber tip and sand it at the same time. When done, clean the plunger again and apply any vinyl/rubber dressing products to the rubber tip - let it soak that up.

You can now reassembly the solenoid to the valve body. As explained in the begging, now touch the battery pack to the terminals on the solenoid, reverse polarity and do it again a few times. This will correctly position the plunger inside the solenoid. You are done. Reinstall valve body back under sink. It will work like brand new again. YOU ARE DONE!

NOTE: These valves are custom made for Delta by Italian company RPE ( and why no internal parts are available. The valve itself is called the R Series 6vDC 2-way Latching Bistable. The term "latching" means it uses magnets to hold the plunger in position, instead of electricity. The plunger tip allows water pressure on one side of the diaphragm or the other, opening or closing the water flow. This method of using magnets to hold the plunger in position allows for little use of electricity, extending the life of the batteries.

To see the valve in operation from the inside, view this video. Disregard the part "a small hole in the membrane connects to two chambers". The Delta valve does not have this hole.

2 Posts
Thanks for the detailed description. I have exactly the same solenoid valve on my Delta touch faucet. The faucet has been installed for seven years now and was beginning to function sporadically. I removed the assembly and discovered the white filter on the intake was almost completely plugged with debris. Being the curious type I removed the three screws holding the solenoid coil and the plunger assembly. I noticed the little dimple in the rubber seal was off-center before I reassembled it. Once I reassembled it and reinstalled the valve assembly the blue light would go on and off each time,but I would just get a little blast of water and then the water would go off. I called the help desk and Delta's solution was to purchase a new valve assembly because there's only a five year warranty on electronic parts and I really didn't feel like spending $170 today.I then discovered your post and took your suggestion and got rid of the dimple that was in the rubber seal. After reassembly again the blue light would go on and off each time I touched the faucet and the water would run properly but the water would not always turn off. I might try to disassemble it a few more times to see whether I missed any debris that's plugging the orifice. Do you have any suggestion that might help this problem? Thanks again for your detailed description of the problem
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2 Posts
After about 25 attempts, I've gotten very good at removing and installing this assembly. Your tip to sand the rubber sealing surface got me one huge step towards success. Once I put a little Rubber Renew (which I still had from the days of reel to reel tape recorders) on the freshly sanded rubber tip and then blew a lot of pressurized air through the middle hole on the plunger of the solenoid I arrived at success. I noted that the magnets in the plunger didn't always hold when pushed towards each other. There must've been a small amount of debris between the mating surfaces. A few blasts of air managed to dislodge this debris. Amazon wants $165 for a new assembly EP74854, and I would've had to wait at least a week to install it. Once again thanks for taking the time to document your experience, Cheers!

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