Antifreeze in Water heater.

dbro60 wrote:
turned the bypass valve off.

Sounds like you should have turned the bypass valve ON.

My advice is put the plug back in to protect threads over the winter months. Antifreeze will not harm the water heater but you may have a leaking check valve. This should prevent back filing of the heater.

What kind of WH system do you have..........1 valve, 2 valve or 3 valve?

1 valve.......3 way valve that controls water to WH cold inlet. Turn it 90 degrees it 'bypasses' WH cold inlet, ties into WH Hot outlet line and a check valve in Hot outlet stops water from backflowing into WH.
If so....BAD CHECK VALVE

2 valve.......both valves have to be set to 'bypass' position otherwise flow to WH is not stopped

3 valve.....cold inlet and hot outlet valves have to be CLOSED and 'bypass' valve as to be OPENED

Improper valving OR bad check valve.
Probably bad check valve.........common problem.
Remove check valve and install another valve.

Here is another post....same problem.....with pictures.....LINK

Just make sure and rinse it real well when you dewinterize. Macktee

Old-Biscuit wrote:
Improper valving OR bad check valve.
Probably bad check valve.........common problem.
Remove check valve and install another valve.

I have one of these in a baggy zip tied to the check valve, just waiting till the valve needs replacing. I will go from a 1 valve bypass to a 2 valve bypass.

Guys, Thanks for your replys. I had two valves. Got it all taken care og.

Thanks, Again,

Dave

skipnchar wrote:
My advice is put the plug back in to protect threads over the winter months. Antifreeze will not harm the water heater but you may have a leaking check valve. This should prevent back filing of the heater.

As a point of clarification, RV antifreeze is very corrosive to anodes, so if you have an anode, don't get antifreeze on it. (information from one of the water heater manufacturers websites)