Outdoor shower causing loss of hot water

bdgood · Nov 16, 2011

I have an outdoor shower that the previous owner installed themselves. The plumbing works fine and looks good. It is very simple with copper pipe and simple lever valves for hot and cold. The hot and cold pipes come in separate, with their own valves and merge together after the valves into one pipe to the shower. Before the shower head another valve allows the user to turn off the shower without changing the mix of hot/cold which is a nice feature.

Here is the problem. If, after taking a shower, the person turns off the one valve before the shower head but does not turn off the hot and cold valves, the next morning, the hot water in the house is luke warm. My only guess is that since the cold water has access to the hot water, this is cooling the hot water in the water heater?

What is really happening?

How can it be corrected without removing the feature to allow the shower to be shut off by the valve near the shower head?

Thanks!

johnjh2o · Nov 16, 2011

What you have is a cross connection between the hot and cold water lines. Allowing the hot to mix with the cold, cooling the hot down. It's not cooling it down at the heater but it's cooling it down in the hot water line before it reaches the fixture you are using. With the present set up you must turn the hot and cold valves off.

John

phishfood · Nov 16, 2011

A check valve on both the hot and cold lines leading to the shower should fix the problem.

bdgood · Nov 16, 2011

Thanks. I was just in the home improvement store and saw check valves the other day and understood that they stopped the flow from reversing but wasn't sure if they stopped the flow completely if there is not that much pressure. In this situation there would not be much pressure in reverse. Do they completely stop the reverse flow regardless of the pressure? Thanks very much