Home>Discussions>PLUMBING>Air in Hot Water Heater Pipes
7 posts / 0 new
Last post
Air in Hot Water Heater Pipes

In the remodeling of my home I've had to redo a lot of things, and part of that has now required me to move the hot water heater into what used to be my very small attached garage, which is now become my utility room. All seemed to be fine with my planning of everything, until I suddenly realized that I can't get the air out of the hot water heater pipes.

Typically or should I say on the old hot water heater the pressure relief valve was on the top of the hot water heater, which made burping the air out a breeze. Although on the new one the pressure relief valve is on the side, and because I've brought the pipes out of the floor up to the hot water heater and then back down into the floor again to feed the various parts of the house (as I have no basement). Now I am finding air gets trapped in the pipes with no way to release it.

I've been considering all kinds of ways to fix it, but I can't come up with anything that would work long term, anyone got any idea's for me? Thank You for reading this, and any help anyone can provide me

Re: Air in Hot Water Heater Pipes

The location of the pressure/temperature relief valve - on top of the water heater or on the side - makes no difference. It should have a 3/4 copper to the outside of the house for drainage when activated. This discharge pipe should not be capped.

To get rid of air in the pipes, you just turn the hot water on at the faucets.

Re: Air in Hot Water Heater Pipes

I don't know if this matter or not, but my water pressure here is only 25lbs. Now there is a knocking in the pipes as they rattle and bang, and the water volume which comes out of the pipes is greatly reduced. I got around this issue right now by adding a valve going up vertical to nothing so I could burp off the air from the hot water side of the valve and pipe coming out of the hot water heater. I know this isn't safe, or even correct, but it is all I could think of to do... Here is a sketch of what I'm trying to say of the pipping issue.

***this looked right when I posted it... not when it posts... Sorry

P l l
I l -------
P l - HOT -
-------l -TANK -
PIPE -------

This is a ruff view of what I mean about the pipes come out of the floor, up and then down into the tank and the same route for the hot and cold water both entering and leaving the tank.

Re: Air in Hot Water Heater Pipes

Just turn on the faucets. No matter what the pressure is the air will come out of the lines. When you turn on a garden hose the air doesn't stay in the hose. What makes you think you have air in the lines?


Re: Air in Hot Water Heater Pipes

It looks like you have multiple issues there, but the water pressure has nothing to do with air in the pipes, and air in the pipes happens only when you open the piping system (like when you change a valve or a supply line). Once the air is out and the piping system is tight, there should not be anymore "air in the pipes" issue.

Why don't you try to send a photo of your pipes. You will need to find a way to do that.

Re: Air in Hot Water Heater Pipes

lost the camera for the moment... somewhere in our construction mess.... will post photos in a day or two.

Re: Air in Hot Water Heater Pipes

Thank You all, I got it fixed... I guess it would seem I wasn't running enough water at a time to get the air to clear out of the pipes, as I would shut it off as soon as the pipes began to hammer. All I had to do was run the water on full for several minutes over a period of time to clear the air and get it all gone Opps... guess it happens to those of us DIY type people who are trying to learn as they go.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.