Hot Topics: What Is This and Why Is It Leaking?

A backflow preventer.

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Original Post: Can anyone identify this device in my cold water line?

fromhollywood Member

This is the cold water line running to my water heater. Does anyone know what the device is that I've indicated with a red arrow?

Hot Topics, What Is This and Why Is It Leaking, backflow preventer

I looked up "Homart" and the only association I could find is something about Sears water heaters. I have a ten year old electric water heater but this is probably some old thing installed on the line from decades ago.

My pressure relief valve recently started putting out a couple of cups of water daily. The only change I had made before this was replacing the heating elements and thermostats. After I saw the water from the relief valve, I replaced that valve too and the anode rod but the new valve is also putting out some water daily.

I'm puzzled on why the relief valve(s) have started releasing water when its never happened before. I don't have an expansion tank but thinking I need to install one and identifying this unknown part is the first step.

Thanks for any advice.

Highlights from the Thread

chandler Forum Topic Moderator

It is a backflow preventer. Water can only travel in one direction. See the arrow on the side. You should probably have an expansion tank on the cold water pipe just ahead of the water heater, if you are on municipal water supply.

Keith Weagle Member

It is a check valve.

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fromhollywood Member

I have a well so would an expansion tank still be advisable? What might have caused the old and new pressure relief valves to start emitting water when that had never happened before? If I install an expansion tank, should I keep that backflow/check valve in-place?

Thanks for your help.

Keith Weagle Member

You say you changed the heating elements and thermostat before the pressure relief valve started leaking? I would say one of those things caused the problem. Perhaps the tank is heating the water more than it used to creating more pressure?

In any case, an expansion tank is the only solution.

Furd Member

Since you have a well you also have a compression tank. You do NOT need an expansion tank for the water heater but you DO need to either remove the check valve or at minimum remove the "gate" from inside the check valve body. You can do the latter by turning off the water and dropping the pressure to zero, removing the cap on the top of the check valve, removing the hinge pivot cap from the side of the check valve body and the removing the pivot pin and the gate. Replace both outside caps and then turn the water on again and check for leaks.

Removing the gate (or the entire check valve) will allow the expanding water to move backwards in the piping to the well pump's compression tank which will absorb the increased pressure. You may also want to change the safety valve on the water heater as the seat/disc may have been compromised due to the leaking.

chandler Forum Topic Moderator

I agree with Furd. On a well, no expansion tank is necessary, and no check valve, either. I believe what is happening is your tank is ahead of the check valve, so heated water has no place to expand. Remove the guts of the valve, rather than changing it out. You can hang the pivot plate on a wire on the valve for posterity if you want rather than throwing it away. If you ever re-pipe, you can recover the valve, replace the guts for a complete unit.

fromhollywood Member

I removed the gate inside the backflow/check valve yesterday. Since then, there has been no leaking from the pressure relief valve and I don't see any other issues that have come up by removing it. I hung the gate on a wire around the valve to keep it and to let anyone know that the backflow isn't functioning as such. I appreciate your help. Thanks very much.

chandler Forum Topic Moderator

Glad it worked out. Well pumps have a built in check valve, so an additional one, especially ahead of everything else is redundant and keeps the expanding water from going anywhere.

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