I don't usually write long posts, so I apologize now.
Hooray! My fresh water shower is finally working right. This has been a journey. While I went through so much frustration to fix a seemingly simple mechanism, I understand why now and will cut Yamaha and the dealer some slack.
This all started from my 9 year old bothering me to use the shower. I don't know that I would have ever used it if he did not push. Each week he would ask if he could use it and of course, I had forgotten to fill it. When I finally remembered and told him to try it, I got nothing. At first the hose from the pump was not connected at all, so we were dumping tons of water into the storage area. When I used a flashlight and searched around, I could see the disconnected hose but had no way to get to it. I took it to the dealer and they pulled the tank and got it hooked up. When I get it back home, I tested and found that the pump was cutting off. Since that time, the boat has spent 8 weeks overall (on and off) at the dealer. Yes, for a shower sprayer. However, I would take the boat there on a Monday, on my way to the airport, leave it there all week and pick it up on my way home. Sometimes, I would leave it there for a couple of weeks if I knew we couldn't get on the water that week. During this time, we managed to get the Yamaha tech liaison to Japan involved, the manufacturer of the pump involved, the manufacturer of the tank involved and the designer of the entire system involved.
So here is the culprit. In the diagram below, notice the area marked "A". It is a fitting that exist between the storage compartment where the tank lives and the hose with the sprayer in the swim deck wall. That fitting connects the hose from the pump to the hose of the sprayer. specifically, item #9 (a $7.00 piece) was stripped and was introducing air into the system that was intern introducing a back pressure that caused the pump to shut off (protection mechanism). This was a hard issue to find. I spoke directly to Yamaha and the dealer everyday. They had a boat out in CA that was exactly like mine and duplicated every step that they asked the dealer to perform. They swapped out every component in the boat related to the shower including, the Connext screen, Connext control module, pump, hoses and the entire wiring harness that goes from the front of the boat back to the engine bay. Imagine swapping all those parts out and the system still not working. Moreover, they put my parts into another boat and that boat worked. Both Yamaha and the dealer were super puzzled. Eventually, the dealer decided to blow compressed air back through the system to see if there were any leaks. Sure enough, while reaching around back there, they could feel the air coming through. They pulled the tank, crawled back there and removed the piece to discover the defect. They swapped the piece with another boat and "viola", it worked!
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