Plumbing: Adding a Second Valve to the Motor Aid loop

by Don and Tys 1999 U270 36′ 7/1/13

This was part of the much larger project of putting the freshwater compartment back together. I replaced the original gate valve with two full flow ball valves. The reason for doing so is to make the job of removing the water heater a bit less messy. When I took our water heater out way back at the beginning of this project, I discovered that just shutting off the one valve that was there does nothing to keep the coolant from pouring out of the other side of the loop… Dah!

Having two valves limits the coolant loss to just what is in the two short lengths of hose that go from the valves to the water heater. It also makes it easier to install and remove because you can just remove the hose after the valve and leave the short sections attached to the water heater instead of contorting to reach behind the water heater. Likewise, I am using some soft hoses to go to the main bloc via a couple of ball valves so you can undo those from the front rather than at the back of the heater. It is a simple project as long as the water heater is out, but one that falls under the category of “while you are at it…”

There is a 12″ X 12″ piece of 3/4″ plywood under the fiberglass skin that starts 4 1/2″ off the bottom and 8″ from the outside edge. I placed the valve mounting block so that I could screw into that to secure the assembly, along with some VHB style double-stick tape between the block and the fiberglass. The mounting block material is some scrap aluminum leftover from another project.

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