From April 2016 Motor Home magazine.
“In regard to the October 2015 letter “Cold Showers Build Character,” there is a solution. The problem is caused because the cold-water pressure is slightly higher than the hot-water pressure at the showerhead. When the water is stopped at the showerhead, because the cold-water pressure is higher, it backflows cold water into the hot-water side. A simple solution is to install a check valve in the hot-water line ahead of the shower-mixing valve.”
Last week I installed this back flow valve in our motor home.
Shower valve access panel is in the bedroom wall behind the sliding bedroom door.
I used this Harbor Freight Multi-Tool I purchased on a discount coupon over a year ago. I think it was like $12.00. This saw edge is thin which will create a very small cut in the wall.
Here is the wall opened up.
My motorhome is plumbed with PEX and the Quick Connects comes with a plug to stiffen for the cut end of the tubing and a lock clip.
Check valve plumbed in, if I do another one of these I would move the valve closer to the end of the tubing.
Here is the final project with the access panels put back in.
Parts List from Amazon:
Homewerks VCK-P40-B3B In-Line Check Valve, Female Thread x Female Thread, PVC Schedule 40, 1/2-Inch
2 of Watts P-610 Quick Connect Male Adapter, 1/2-Inch CTS x 1/2-Inch MPT