# Hissing Water Heater



## dtheobald (Nov 7, 2011)

Hi, My wife and I just purchased our 1st home. It has been vacent since March of this year, so it has some cobwebs so to speak. We have two gas water heaters, and when I turned them on yesterday they fired right up. A little while later one of the water heaters starting hissing pretty good. I had it set on the 'C' level on a four step scale with 'D' being the highest. So, I lowered it all the way down till the hissing stopped. Then I raised it to A, and no hissing, then B, hissing...so I lowered it back to A. IT takes a little while or the water to get hot from the faucet in the kitchen, but once its there its hot. 
Could this hissing be due to it sitting for so long? Should i do a flush and see what happens? 
I did a visual insection and saw no pressure relief valve discharge. Is this a case of it sitting and needing some action?


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## Redwood (Nov 7, 2011)

Sounds like a sediment build up in the bottom of the tank.
Flushing may or, may not help...


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## paul52446m (Nov 7, 2011)

dtheobald said:


> Hi, My wife and I just purchased our 1st home. It has been vacent since March of this year, so it has some cobwebs so to speak. We have two gas water heaters, and when I turned them on yesterday they fired right up. A little while later one of the water heaters starting hissing pretty good. I had it set on the 'C' level on a four step scale with 'D' being the highest. So, I lowered it all the way down till the hissing stopped. Then I raised it to A, and no hissing, then B, hissing...so I lowered it back to A. IT takes a little while or the water to get hot from the faucet in the kitchen, but once its there its hot.
> Could this hissing be due to it sitting for so long? Should i do a flush and see what happens?
> I did a visual insection and saw no pressure relief valve discharge. Is this a case of it sitting and needing some action?


When you start them up with well water temps. they will make a hissing noise because the tank is condensating, as soon as it get hot it will stop that. Paul


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## dtheobald (Nov 8, 2011)

paul52446m said:


> When you start them up with well water temps. they will make a hissing noise because the tank is condensating, as soon as it get hot it will stop that. Paul


Thanks for your reply

Well, I dont know how long to let it run for hissing??? its really pretty loud, and it also sounds like there are rocks turning in it.
It makes me a little nervous. Am I wasting my time attempting to drain it???


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## dtheobald (Nov 8, 2011)

Redwood said:


> Sounds like a sediment build up in the bottom of the tank.
> Flushing may or, may not help...


 
...meaning, I am stuck with a hissing water heater until we replace it? Thats OK, as long as it is safe to run it. 

Our home has two water heaters, and this one serves the kitchen and laundry room only...


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## joecaption (Nov 8, 2011)

Any old tank builds up sediment in the bottom of the tank as it gets heated it pops up off the bottom and breaks up. 
When that tank was new there was instutions in the manual to attach a garden hose to the tap at the bottom of the tank and drain off some of that sediment. Almost no one ever does that, if they did they could help that tank last far longer.
By now nothing may come out because it's built up to much and will just plug up the valve before it can be drained down. But it's worth a try. If nothing comes out of the hose sometimes removing the hose and sticking a metal coat hager in the hole can free it up enough to get it running. It will make a mess when you do this so be ready to shut it off and have towels ready to wipe up.
A gas heater is suppost to be sitting on a stand, and in a pan made just for heaters, to keep it up off the floor for several reasons, one to get it above the floor to prevent drafts blowing out the flame, if it's in a garage or basement to get it above any fumes that may build up there at floor level.
The pan is suppost to have a drain on it to drain away any water that leaks from the tank that goes down  through the floor, or leading outside. But almost no one does that. It's a shame because that one thing can prevent thousands of dollars in damage. I even have my safety relief valve piped to an outside wall.


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## dtheobald (Nov 8, 2011)

joecaption said:


> Any old tank builds up sediment in the bottom of the tank as it gets heated it pops up off the bottom and breaks up.
> When that tank was new there was instutions in the manual to attach a garden hose to the tap at the bottom of the tank and drain off some of that sediment. Almost no one ever does that, if they did they could help that tank last far longer.
> By now nothing may come out because it's built up to much and will just plug up the valve before it can be drained down. But it's worth a try. If nothing comes out of the hose sometimes removing the hose and sticking a metal coat hager in the hole can free it up enough to get it running. It will make a mess when you do this so be ready to shut it off and have towels ready to wipe up.
> A gas heater is suppost to be sitting on a stand, and in a pan made just for heaters, to keep it up off the floor for several reasons, one to get it above the floor to prevent drafts blowing out the flame, if it's in a garage or basement to get it above any fumes that may build up there at floor level.
> The pan is suppost to have a drain on it to drain away any water that leaks from the tank that goes down through the floor, or leading outside. But almost no one does that. It's a shame because that one thing can prevent thousands of dollars in damage. I even have my safety relief valve piped to an outside wall.


 
Thanks for the information. 
I will try and drain it out. I hope it works. I will have the 'wire hanger' option on my side as well. The house used to be occupied by an older woman, who probably didnt need 3k sqft and 2 water heaters...so, sadly this 11 year old water heater probably never had enough use, and may be damaged due to lack of use...just in time for me and my family to move in...Its funny...this is my first home owner issue...I signed up for this.


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## joecaption (Nov 8, 2011)

The tank does not needed to be drained, it just needs a few gallons drained out. I never shut it or the water off when flushing it out. You need to have water pressure to push the water out.


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## Redwood (Nov 8, 2011)

The Popping Sound is a classic sediment noise!

Does Your Water Heater Sound Like A Pop Corn Popper?

A thick layer of Sediment builds up in the bottom of the water heater tank as minerals such as lime precipitate out of the water as it is heated. This sets up a barrier between the water in the tank and the heating on the bottom.

Water pockets in the sediment are heated and turn to steam exploding out of the sediment. These little pops while harmless signal that the heating efficiency of your water heater is much lower than when new.

When you get to this stage the sediment is seldom able to be removed via flushing. So you are probably stuck with the noise untile you get a new water heater.

The most effective flushing is done with a full drain down, and not removing a gallon or 2 of water. The object is that once empty the incoming water blasts into the mineral deposit and breaks it up forcing it out the drain under pressure. Read about how to flush a water heater at this link along with how to change the anode rod here which may be of interest to you if you have any success in getting the sediment out....


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## dtheobald (Nov 9, 2011)

well, I figured out what the hissing is...it has to be the pressure relief valve. I was out side on the telephone and I saw hot water coming out of a copper pipe on the side of my house. I went inside and sure enough, the water heater was hissing, and that has to be the pressure relief valve. 
I havent drained it yet, but I will today, after work. I am doubtful that will fix this thing.


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## joecaption (Nov 9, 2011)

Sometimes simply lifting the trip level on the relieve valve and flipping it back down will reseat it. Water out of the tap should be no more then 120 Deg. if the heater is set to high it can cause it to leak or trip.


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## Redwood (Nov 9, 2011)

The valve you are describing is called the T&P Valve. As Joe described many times raising the lever and snapping it back down will reseat the valve and stop it from leaking.

There are also 2 legitimate reasons why it may be leaking which will have to be checked if snapping the T&P lever doesn't work.

The valve opens when the temperature or, the pressure is too high, so those should be checked. If those are within the limits then the valve has failed and should be replaced.

Here is some reading on the subject...
The T&P Valve On My Water Heater Is Leaking

Thermal Expansion Tanks For Water Heaters


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## dtheobald (Nov 10, 2011)

OK, I drained it, flushed it...a bunch of stuff came out of there...so I was hopeful. I fired her up and the popcorn popping sound...well, it sounded more loose, if that makes any sense. But the hissing came back. I dont have internet at my house, so I am printing those articles out redwood. Thanks.


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## dtheobald (Nov 16, 2011)

OK, just an update if anyone is interested. 
The pressure relief valve was shot. The hot water heater sounded very bad and was loud. So, my wife and I agreed to purchase a new one. I removed the old unit, and noticed that the pressure relief valve was removed from the side and placed on top of the hot water 'out'. This made it closer to the pressure relief drain out of the house, but it didnt seem right. Both hot water heaters have warnings about removing the pressure relief valve and placing it some where else...
Also, The water main into the hot water heater had issues at the stop valve. It wouldnt seat all the way, and it would leak when full open. 
I removed the old unit, shut of the main to the house, and replaced the stop valve line into the unit. Turned the house water back on, no issues. 
Then onto the installing the unit. 
The pressure relief pipe was on the opposite side of the pressure relief valve, so I hade to run copper pipe from the wall, around the unit, and then up to the hot water heater. I braced the new pipe on the wall with a 2x4 and copper straps for added earthquake protection (I Hope). 
Fired her up, and she runs great...whisper quiet, and great hot water. 

Thank you gain for all of your assistance.


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## joecaption (Nov 16, 2011)

I hope you installed a ball valve for a shut off. Shark makes one that just slips on over the copper pipe, no tools needed.
You could have saved a lot of trouble by using Pex to plumb the relief valve with a simple slip on Shark fitting.
I believe you will find it's code in CA that  heater also needs to be strapped to a wall to prevent it from tipping over.


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