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SpringerPop · 04-14-2017, 03:49 PM

I decided to sanitize our fresh water system today for the first time.

When I went to bypass the hot water heater, I found only two valves, not three.

In the photo attached, there appears to be some kind of extra piece at the outlet port of the heater, and I wonder if it's a check valve, as it MIGHT do the same thing as a ball valve if it doesn't leak backward. Of that, I'm not sure, however.

If you were in my shoes, would you add another ball valve in the outlet piece of red PEX?

Pop

Spk64 · 04-14-2017, 06:07 PM

Another valve would totally block but with the inlet side closed and the outlet bypass open. The water will take the path of least resistance and bypass the water heater as long as water was in there to start with.

SpringerPop · 04-14-2017, 10:24 PM

Of course, I drained the tank prior to beginning this project, so heavily-chlorinated water would likely back-flow into the all-aluminum tank.

Should I trust that twelve-year-old check valve (if that's what it is)?

Pop

RKins · 04-15-2017, 04:52 AM

From what I've read you want to sanitize the water heater too. You want to bypass when winterizing.

nothermark · 04-15-2017, 05:40 AM

If it still works I'd leave things alone. If I had to get into the check valve it would be a ball valve when I got done. I just don't see a check valve as more reliable than a ball valve and as long as I have to get in there to turn 2 one more won't be much of an issue.

The issue heavily chlorinated water got me thinking so I did a bit of poking. As usual the answer is "it depends but probably not". Here is the paper:

https://nickelinstitute.org/~/Media/...ter_14049_.pdf

It appears that choosing the proper alloy allows limits the issue. Given the life expectancy of RV tanks that are routinely sanitized as part of spring dewintering that seems to have been done. Heavily chlorinated water would fill the tank and sit for a few hours or so at most. Usage would then start decreasing the amount of chlorine fairly rapidly as fresh water was introduced as the hot water was drawn out. I don't think I'd take a shower as my first move. Might help clean the dishes. ;-) It's part of why we carry some jug water for the first tank of usage.