[Barrowboy]

Hello I recently installed a new hot water tank the 4th one I have installed. After purging the tank I found air in the hot water only. Each morning it would be there. I drained the tank fully and refilled only to find air at the top of the tank again, I have no leaks and am on city water. Could the Vacuum relief valve somehow allow air into my tank.? getting frustrated.

 

[chandler48]

How do you determine there is air at the top of the tank? There may be a faulty check valve, but you would find air in the cold water as well as hot if that was the case.

 

[Bondo]

After purging the tank

Ayuh,..... How are you purging the tank,..??

 

[Barrowboy]

Just emptying and then opening all faucets (hot) until a steady flow is reached.

 

[Barrowboy]

The Vacuum relief valve is probably 30 years old. everything else is new, never had this problem before

 

[chandler48]

What are you calling a vacuum relief valve? The T&P valve? Is it leaking?

 

[Yodaman]

A bad expansion tank can introduce air into the line, if you are using one.

 

[Barrowboy]

No expansion Tank on my system Yodaman.

 

[Barrowboy]

What are you calling a vacuum relief valve? The T&P valve? Is it leaking?

nope the T&P is fine its the Vacuum relief valve on the cold water input I was wondering about.

 

[Barrowboy]

VRV is designed to allow air into the tank if the tank tries to collapse. at least thats what I am led to believe.

 

[Barrowboy]

How do you determine there is air at the top of the tank? There may be a faulty check valve, but you would find air in the cold water as well as hot if that was the case.

Its takes the hot water about 10 seconds to get to the nearest faucet and then is spurts with a small amount of air , hot water comes from the top of the tank so I assume thats where the air is collecting . I am stumped

 

[Barrowboy]

https://www.homedepot.com/p/Watts-1-2-in-Brass-MPT-Vacuum-Relief-Valve-1-2-LFN36M1/202922389

 

[Yodaman]

I have never seen one on the potable water line. Seems like something belonging on a boiler and tank system.

There are a couple professional plumbers kicking around here. One of them will find you.


Are you on a well pump or municipal water?

 

[TheEplumber]

I have never seen one on the potable water line. Seems like something belonging on a boiler and tank system.

There are a couple professional plumbers kicking around here. One of them will find you.

They are becoming more common, especially when the tank is elevated to the ceiling or second floor.

I can't think of any reason to have air entering your system since you are on city water. I'd replace that valve. 30 years old right?

 

[Ghostmaker]

If his tank uses side inputs on the hot and cold he needs a vacuum relief to protect his tank from collapsing if a water main breaks.


Replace it they don't cost that much. Since your hot to the house comes out the side you may have air at the top. Is your [email protected] relief off the top of the tank. If so open it to release the air.

 

[Barrowboy]

my inlet and outlet are on the top . The vacuum relief valve is on the Cold water line but not inline its offset a little off a 90. I think I will replace it . Thanks for your input everyone
It is a head scratcher

 

[hkstroud]

Why would you want that thing. The only way your tank could collapse would be if the fire department came and began pumping water out of the municipal system so fast it created a vacuum in your tank. Even then I doubt that your tank would collapse. Cylinders have more pressure resistance from external forces than they have from internal forces.


It is something someone invented to prevent something that is highly unlikely to occur and some bureaucrat thought was a good idea. Same kind of logic that led us to the vacuum breaker on hose bibs.

Remove and discard it. Cap the fitting.

From a former bureaucrat.

 

[Ghostmaker]

I would just remove it then Your dip tubes built into a top feed tank prevent the tank from collapsing.