How to Flush a Water Heater

[Tumbleweed]

Thought I'd create a separate thread since Cactuspatch asked how to do this. I'm glad she asked because I need to do this ASAP. I've done it only once since I lived in this house and it has been ages ago.

By the way, my water heater is gas so I only know how to do gas.

First turn the water heater on "pilot" (D) so the burners don't come on. VERY IMPORTANT as your heating element could burn out very easily if the water level drops below the heating element. Anyway, it should be clearly labeled "pilot". This water is HOT so be very careful!! I know, duh.

Connect a garden hose to the drain valve (F) located at the bottom of the tank. Orient the end of the hose to empty into your floor drain or sink.

Shut off the cold inlet valve (A).

Open the relief valve (H) and leave it open.

Open the drain valve (F) and let it run until it looks clean.

Note: My water heater is relatively new but I have heard of people having so much gunk in the bottom that the water doesn't drain out. In this case you have to turn the cold water valve back on to help move this gunk out. If this doesn't work you may have to make this a long process by allowing the water too cool in the heater and then digging it out with a unbent clothes hanger or some object you can stick in there. If you have to resort to this, it would be a really good idea if you put a pan
or something under the valve while you dig out the debris. Don't forget to let the water cool off! And once you get it free-flowing shut the cold inlet valve off again.

Once the water looks good you can

• close the drain valve
  
• close the pressure relief valve
  
• turn on the cold inlet valve
  
• remove the hose
  
• Turn your water heater back on *
  

Oh and a couple notes: Something I forgot to do last time.....go to a sink and run the hot water until all the air pockets were gone. Since I forgot this last step last time, later when I went to turn on the hot water it made such a big sputtering noise it scared the heck out of me. Almost gave me a heart attack.

* Make sure you still have a pilot light on ,as if there is a breeze, it may have blown it out. If it is out, I can't tell you how to light it. (Me and lighting furnaces and water heaters do not get along, LOL)

Here are some photos of my water heater so you know what parts are what. Sorry I couldn't get back far enough to give you a full view. These photos are not click-able for a larger view.







A. Cold Inlet Valve
B. Flue (nothing to do with flushing your water heater)
C. Hot Water Inlet
D. Pilot
E. Heat adjuster/thermostat (nothing to do with flushing your water heater)
F. Drain Valve
G. Panel comes off to light the pilot
H. Relief valve

Consider this a fair warning! If you have a very old water heater you know has never been flushed do not be surprised if, after removing the debris from the bottom of the tank, you also uncover a hole (leak) where the metal has rusted through.

[Tumbleweed]

I did a little web search and for those who have an electric water heater I guess you need to shut off the circuit breaker and then basically proceed as per my instructions above.

[cactuspatch]

Thank you. I always feel so stupid like I should somehow know these things. Your pictures and information are great. We've haven't flushed our water heater since we moved in, in 1999. Embarrassing.

[Tumbleweed]

Don't ever, ever feel stupid. Girls just aren't taught these things, normally. That is primarily why I started this site - for men and women who haven't had the advantage of having a father figure in their lives to pass down the knowledge. And there are more and more men these days that grew up without father figures to teach them about fixing cars, home repair, etc.

[Nigel]

JJ thanks for the info: we've lived here for 11 years and haven't done anything about the water tank (well it's not really a tank it's more of a cylinder shape)(w0w I spelled cylinder right, or did I?). It's probably close to 20 y/o at least and I Know the former owner didin't do didley as we spent 3 days just cleaning the inside of the house after we moved in.

Gota go, #1 son needs to use computer.

[Tumbleweed]

A word of warning Nigel or is it John, I get you two so confused. If you haven't flushed out your water heater - that cylinder thingy - in that many years you may have so much gunk in the bottom that removing "the gunk" may reveal a hole and thus a leak.

Get a mirror and try to look at the underside of your water heater, if you can, or feel with your hand (ouch, watch out - it is very hot!) and see if you feel any weak spots or areas that are so rusted they may leak. You may want to think twice about flushing it unless you know how to patch the leak or have the $$$'s to buy a new one.

In fact, I may just put a warning with my original post. BTW: The same is true with your car radiator. If it is very old and never been flushed you are better off not flushing it.

[Nigel]

:(JJ that's a great idea about the mirror, I think I'll give that a try . . .