knocking sound on gas water heater?

[orioncyg]

I have a 50 gallon AO Smith gas water heater on the 3rd floor which is used for supplying hot water to the bathroom on the 3rd floor only. I haven't used it since I moved in to this house in December of last year because no one currently lives on the 3rd floor and the water heater went out right after I moved in, and I haven't gotten around to fixing it until this past week.

It's like 11+ years old, so it's at its expected end of life, and I was considering getting the whole thing replaced (would cost around $2k where I live), but before I did that, I bought a new pilot assembly and installed it and was able to get the pilot to ignite.

I've been running it for the past 15min, and I'm hearing some loud knocking sounds

https://imgur.com/AYOdnNF

Based on my readings online, it seems this could be due to sediment build up in the pipes or tank, and I should flush out the tank to solve the issue?

 

[Reach4]

Loud? Normal sounds are not loud but loud is relative, I guess. Can you hear that sound on the second floor?

Still, flushing seems worth doing. See https://terrylove.com/forums/index....o-flush-a-hot-water-heater.79444/#post-576623 post #7.

 

[Sponsor]

 

[GReynolds929]

Sediment is heating up creating steam pockets that flash and cause popping banging noises. I would not recommend draining it at this age and being on the 3rd floor. There is a high risk of a leak developing if drained. I would replace at this point before it leaks to avoid the water damage that will happen when it leaks.

 

[Sylvan]

I often wondered how many cars people replace after 10 years??

 

[Master Plumber Mark]

That is a fairly old heater.... best to leave sleeping dogs lie ..

Install a new unit and install it in a drain pan

 

[Jeff H Young]

11 years is up there is a good life id recomend a leak alarm for around 10 bucks whether you replace it or not.
if you want to attempt extending the life install new ball vave at drain drain/ flush multiple times concide a new anode and a 1/2 days work and cross your fingers maybe leave the anode , but you need to change that valve on bottom also you could try one of those gimmicky crud buster or sediment buster do dads thingys and pray

 

[Master Plumber Mark]

I just had one of my heaters that was only 10 years old in a condo start to leak and I can tell you
that those cheap shitty OATY pans that were the best you could buy 10+ years ago will leak just
from the weight and compression of heating and cooling will eventually grind a hole through that plastic pan.
# if the heater is not installed on bricks in the pan and sitting directly on the plastic they will find a way to
wear down that plastic and punch a hole through it over time...

and of course you wont know that pan is bad and leaking till it pisses all over the place....

This person was the third owner of the condo since I installed the heater in 2015. The leak was caught in time before it
had done any real damage to their floating floors in the laundry room..... No floor drain anywhere near by neither
and I am not responsible at all

Just saying that your heater is older than 10, you have a shitty plastic pan underneath the heater that may or not be
good any longer, and you are on the third floor of a condo.......

what could possibly go wrong???

good luck

 

[Slomoola]

If it was mine, I would get a full port 3/4" drain valve and flush the sucker out. If the tank later leaks and fails, you can remove and keep it. Nothing lost here. This will cost you $29.95.

Replace the side over pressure blow off safety valve. While there, look inside the tank at the drip tube. replace that if necessary. This will cost you say a rough $20.00. Can remove and transfer to a new tank if needed.

Finally replace the anode with a powered anode rod. This will cost you $159.00. Way cheaper than replacing the tank. It might run another 10 years or more. Can remove and transfer to a new tank if needed.

$159.00
29.95
20.00
-------------
= $208.95