removing Sediment from Hot Water Heater

[petesgarden]

So for the last several months my hot water heater has been sounding like a popcorn machine when it is heating up. I'm suspecting sediment. I did one flush (hooked up a hose + opened the flood gates for 10 minutes) and some small white flakes came out, but not much. And the knocking isn't any better.

So I've read that you can use vinegar to help dissolve the sediment - but I'm wondering how to get it in there (I don't want to cut pipes or pull out that rod thing or whatever).

What I was going to try was to turn off the cold water intake, open up a hot water faucet, and then drain the heater through a hose. When empty, I have a small pump used to drain a humidifier w/ a garden hose. So I was going to hook that up to the drain valve and 'pump in' a gallon or so of vinegar, let it sit overnight, then flush it back out.

Should that work or could that cause damage? I really think I need a new heater, but I'm hoping for it to last over the winter.

Also is the sediment causing any damage or is it just noisy?

Thanks!

[Gary Slusser]

That pop corn sound is steam explosions in and under the hard water scale build up on the inside of the tank. They will break the glass lining exposing the mild steel which will rust through causing the heater to leak.

To prevent the build up, you need a water softener. That will stop the build up and the softened water will dissolve the build up but it may be too late for this heater.

Vinegar, being an acid, is a choice but that can cause a mess of small pieces of scale blocking the drain valve or tank outlet if you remove the valve.

[petesgarden]

So is there anyway to tell if the glass has broken yet?

Do you see any harm in pumping in the vinegar via the drain valve? If not is this my best approach at the moment w/out replacing the whole heater?

Many thanks,
-Pete

[Gary Slusser]

If your hot water starts going rusty, the glass is probably broken.

IMO vinegar is not strong enough to dissolve much scale build up and it will take you a long long ti,e to get rid of just an inch of scale. I have seen oil and gas water heaters with up to 12" of scale in the bottom and 1-2" on the side and on the flue pipe that runs up through the center of the tank.

If I was adding anything, I would add whatever by removing the T/P valve and then install a new one to replace the old one because I would open the old one to be able to drain the tank. And once opened they tend to not ever close properly again.

[HayZee518]

CLR is said to dissolve- rust and deposits. but if there is a build up of sediment in your tank bottom - Imo I don't think anything will dissolve it. the sacrificial anode that is installed in your tank top, coats scratches with a layer of zinc to slow down the rusting process should the liner become scratched but large areas it will not coat. another thing, I don't see how they can glass line a tank. glass is a solid it isn't flexible even in a task of a water heater. I think the glass lined means the insulation between the tank and the outside shell. if your tank has survived ten to twelve years I'd say its life is about up.

[Gary Slusser]

I've seen the glass lining and always assumed they spray molten glass on the inside of the tank.

[jnaas2]

They sell a product called calci solve but you can only get it at plumbing supply houses, we use it to remove calcium deposits from circulating pumps and and high effecient tube water heaters and boilers, and it does work. Ive taken apart recirculating pumps and put the parts in calci solve and it will completely remove calcium deposits. If you cant get it, and dont want to spend the money on a new water heater remove either the drain or gas valve and take a shop vac with a piece of pex tube taped to the hose and you can remove a lot of the deposits that way. Its a pain but it will last for a while longer