Noise Issue

[usnj01]

Hi,

For a last few days I have been hearing popping noise from my natural gas based water heater, it sounds much like when you make popcorn in a microwave.

I have already done "flushing" a few times to clear any sediments... there was some (very little) debris the first time I drained water but nothing at all on the second and third attempt.

I called American Water Heaters for assistance. I was asked to look into following things:

1) Drain the water heater and flush and drain with a gallon of Vinegar. - When I asked how I can get the Vinegar in i was told to put it in thru the inlet pipe. But I really dont want to remove any pipes / elbows.... is there any way to get it in without any plumbing work?

2) Check Orifice and see if its broken...

This one I looked form outside and the burner appeared working fine and I didnt hear noise from the burner it self. I dont understand how that can cause popping noise...


The noise is persistent and has been getting louder/frequent compared to when it started initially. I've checked everything I can from outside and not sure what would a plumber do without opening up the unit (which I doubt they would do in the first visit)... really dont want to waste money for just a "visit". Any help in diagnosing the problem will be greatly appreciated.

Thanks.

[SewerRatz]

One thing you can do after draining the tank remove the drain valve and poke around in there with a stiff wire coat hanger. After you done that a few times, put the valve back on with a hose attached and turn the water on with the drain valve open. after the water starts to clear turn water off again, remove the valve and repeat, till you do not get any more deposits.

Another way is to call a pro and have them use Un-Lime from AO Smith to delime the tank. This is a costly option some times its cheaper to by a new water heater.

[usnj01]

One thing you can do after draining the tank remove the drain valve and poke around in there with a stiff wire coat hanger. After you done that a few times, put the valve back on with a hose attached and turn the water on with the drain valve open. after the water starts to clear turn water off again, remove the valve and repeat, till you do not get any more deposits.

Another way is to call a pro and have them use Un-Lime from AO Smith to delime the tank. This is a costly option some times its cheaper to by a new water heater.

I can try the hanger thing but thats a lot of water to drain as its a 75 gallon tank. But before that I'd like to understand one thing. Is deposits the only issue for popping noise or can there be anything else which might be causing it? The heater is only 2-2.5 yrs old. Also, how severe is this problem and what will happen if I keep ignoring the noise issue (I know bad idea but I just want to know the worst case scenario).

[jadnashua]

Mineral deposits can cause localize hot spots and it can get hot enough to cause bits to flash into steam. That mini explosion is probably what you're hearing. Sometimes a small leak dripping on the burner can make some weird sounds, but more like hot grease on a fire than popcorn popping.

[usnj01]

So sediments can be the only cause for popping noise?

[Redwood]

Pretty much...
It's a good thing to regularly flush a water heater...
More efficient heat transfer...
No pop corn in the tank...

[glnow]

Mineral deposits can cause localize hot spots and it can get hot enough to cause bits to flash into steam. That mini explosion is probably what you're hearing. Sometimes a small leak dripping on the burner can make some weird sounds, but more like hot grease on a fire than popcorn popping.

Can these "mini explosions" occur in the hot water pipes downstream of the heater, if the mineral deposits have traveled down the line?

The final (long straight) section of pipe that runs to my kitchen makes a what I'd call a popping sounds when it first heats up. I've looked under the house but I can't find any locations where the thermal expansion of the pipe might be constricted, so I’m wondering if deposits in the line could be the cause.

If so, is it possible to purge the deposits from the line? Perhaps by running the kitchen sink for a while with the mesh screen removed?

[jadnashua]

It takes a significant heat source to cause water to flash into steam...so, no, downstream of the heater, it's not the same thing.Expansion and contraction noises can carry along a pipe run making it hard to isolate sometimes.

[Redwood]

So sediments can be the only cause for popping noise?

Unless you are using human supplied methane gas...
Then there might be other reasons....

[jimbo]

When the water heater is limed up bad enough for that rumbling to occur, then it is beyond anything a flush would help. Live with it until you are ready to replace the tank.

[hj]

The noise is caused by rust nodules which have built up on the center flue of the heater. Water enters them, is heated to superheated steam temperature by the flue gases, then is expelled into the water where it instantly condenses releasing its energy in the form of a miniexplosion. These nodules cannot be removed, but eventually, hopefully before they make a hole in the tank, their opening will gradually increase in size so the water can circulate through them to be gradually heated, and not be trapped.