Questions about flushing my water heater


  #1  
Old 06-14-24, 07:11 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
Questions about flushing my water heater

Hello. I have an AO Smith ENLB-40 110, 38-gallon electric water heater. I linked to a short video below so you can see it. I have the manual and I've watched some Youtube videos. I'm about ready to flush it. Here is my rough plan:

1. Turn off circuit breaker for water heater

2. Open hot water faucet and let hot water run until cool

3. Connect garden hose to drain valve

4. Turn the main water supply valve off

I have questions about steps 3 and 4.

Step 3 question: Do you have a specific recommendation on the type of garden hose to get? Avoiding leaks is important because I live in a high-rise.

Step 4 question: Should I turn off the main water supply valve? In some Youtube videos, they don't do that, saying that leaving it on increases the flow strength. In other Youtube videos, they turn off the main water supply valve and let the tank drain completely. Then, they turn it back on for 30 seconds at a time, letting it drain again completely each time. Which method do you recommend?

5. Either way, I know I will have to open the drain valve on the water heater with a screwdriver.

Last question. If I leave the main water supply valve on the entire time, should I turn it off before of close the drain valve on the water heater with a screwdriver? Or can I just leave it on?

Thank you!

https://www.youtube.com/watch?v=HvkA8jRRdv8

 
  #2  
Old 06-15-24, 03:37 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,816
Received 875 Upvotes on 766 Posts
I leave the breaker and water on and drain off a few gallons about 3 times a yr.
Unless your temp is turned way up I'd think most any garden hose would suffice.
 
TonySexton voted this post useful.
  #3  
Old 06-15-24, 04:48 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,386
Received 2,326 Upvotes on 2,068 Posts
I leave the water on and the power to the heater on. Just hook up a hose and open the drain valve. I run the hose into a bucket so I can see what's coming out. I keep letting the water run as long as sediment or cloudy water comes out.
 
  #4  
Old 06-15-24, 06:34 AM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
It's safe to leave the power on? This is an electric water heater.

Do you have a garden hose recommendation? Do I need a specialized one to prevent leaks? Edit: If it's safe to leave the electricity on and the main water valve open, and if I should drain into a bucket, I suppose I would need a short hose.

Second edit: Just about any garden hose would work. I was reading too fast. The water is hot but not cranked way high.
 
  #5  
Old 06-15-24, 06:56 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,816
Received 875 Upvotes on 766 Posts
Leaving the electric on is only an issue if you allow the water level to drop below the heating element. No reason for that to happen if the water isn't turned off. You are unlikely to drain it faster than it can refill.
 
  #6  
Old 06-15-24, 07:15 AM
W
Member
Join Date: Jun 2023
Posts: 115
Upvotes: 0
Received 32 Upvotes on 26 Posts
Any sediment you have in your tank will be on the bottom of the tank. The best way, I think, to get that out is to drain the tank all the way down with the intake turned off. Once it is drained you then turn on the water intake fully. This will stir up the stuff on the bottom and help get rid of any sediment. I let the water run for a minute, shut it off, let it continue to drain. I go through this cycle a couple of times keeping an eye on the drain hose to see what's coming out, If you do it this way you have to shut off the power first to avoid damage.
 
TonySexton voted this post useful.
  #7  
Old 06-15-24, 01:02 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
Help!!! The water is not draining from the water heater very much at all.

I did exactly what the manual said to do. I:

1. Turned the circuit breaker off
2. opened a hot water faucet and let the water cool
3. connected a garden hose to the drain valve and put the other end in the toilet to drain the water
4. turned the main water supply off
5. Opened the drain valve with a screwdriver by turning it to the left about a quarter turn until it stopped
6. Opened a hot water faucet to help the water drain faster

The water didn't start coming out until I opened a hot water faucet. It started coming out, but then it stopped like a minute later. There's no way an entire tank could have drained that fast. Here's a video showing my setup:

https://youtu.be/pIzgv_ctG0c
 
  #8  
Old 06-15-24, 01:05 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,993
Received 4,154 Upvotes on 3,730 Posts
Although draining the tank completely is one way to accomplish this tank... I've never done it.

I have a gas water heater. I hate to waste hot water.
I turn it off the night before.
I use an old washing machine hose and drain it into a 5 gallon bucket.
I drain until clean. Typically two buckets max.

I use a double valve setup.
Water heater valves rarely shut off completely.
I put a good grade of brass shutoff valve on top of the water heater valve.
I use a little never seize on the threads. Vaseline will do.

If you don't want to use a second valve.... have a cap on hand.
 
  #9  
Old 06-15-24, 01:25 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
I appreciate the last post, but it went over my head. You know I'm not the best at this.

Let me see if I can simplify.

38-gallon electric water heater. The power is off. A garden hose is connected. The main water is off. I opened the valve on the heater. No water flowed. Then I opened a hot water faucet and got okay flow for about a minute. Then no flow. I opened the main back up and filled up the equivalent of several large buckets. The water is coming out cleaner now. No more large dark particles, and several little of the stuff that looks like thin sand.

But, when I turn the main off, I get no water flow still.

What else is there to do?
 
  #10  
Old 06-15-24, 01:31 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,993
Received 4,154 Upvotes on 3,730 Posts
With the water supply shut off..... there is a vacuum on the tank.
Opening a hot water faucet can partially reduce the vacuum.

It's much quicker and easier to leave the water turned on.

You could open the T & P valve to relieve the vacuum BUT that could cause it to leak.
 
  #11  
Old 06-15-24, 01:37 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
I had to try something because the water wasn't draining. So, with the hose connected, I opened the main, which let water through the hose. Some debris definitely came out. After doing that for a while, until the water was fairly clear, I turned the main back off.

The hose is still connected, the the water valve on the heater is still open. Now the water is draining even though the main is off. So I am going to let it drain all the way down.

So my understanding is that, once the water has drained all the way out, all I need to do is close the water valve on the heater, opened the main back up, and fill up the heater. How will I know when the heater is full again?
 
  #12  
Old 06-15-24, 02:45 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,993
Received 4,154 Upvotes on 3,730 Posts
You need to check for water at a hot water faucet.
Don't turn the power back on until there is water coming out the hot faucet.
 
TonySexton voted this post useful.
  #13  
Old 06-15-24, 04:53 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
Another DIY job successfully completed thanks to DIY.com. Thanks!
 
  #14  
Old 06-15-24, 07:56 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,993
Received 4,154 Upvotes on 3,730 Posts
Good job.
 
  #15  
Old 06-15-24, 09:58 PM
W
Member
Join Date: Jun 2023
Posts: 115
Upvotes: 0
Received 32 Upvotes on 26 Posts
A trick I used years ago when I had a water heater that would not drain was to backflush through the drain valve. If you have access to a faucet, a couple of pieces of hose, some hose male/female adapters and a Y valve like the one below. (You will need to use male/female adapters or cut the hoses and replace the ends as needed). Connect a hose from the water heater to the Y valve on the side marked A. Then connect a hose from a faucet to the B side. Then you need another hose connected to C and that runs out to somewhere where it can drain. Now you can open the drain valve on the water heater and when it stops draining, shut off the Y valve on the drain side (C) and open the side connected to the faucet (B), Open the faucet and water will run into the water heater and stir the sludge up. Do this for a short burst then shut off B, open C and drain. Works well if you're trying to stir the junk on the bottom of the tank

 
sdodder voted this post useful.
  #16  
Old 06-16-24, 04:32 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
Okay, I'll keep that trick in mind going forward. I don't think mine is that clogged yet.
 
  #17  
Old 06-17-24, 06:08 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,625
Upvotes: 0
Received 296 Upvotes on 271 Posts
I'll keep this part simple, without lots of words or paragraphs.
Before draining water from a water heater, shut off its heat. The "pilot" setting if any is okay. The "vacation" setting if any is not low enough.
Don't turn the heat back on until you have water gushing out a hot faucet for a full minute.

You might need to drain out only a little water but it is too easy to forget and drain out too miuch and then the heater kicks on and damages itself.

******
Depending on make and model of heater, draining may carve a channel in the layer of sediment at the bottom of the tank and the water then runs clear. leaving a lot of sediment behind. Repeating the procedure every 6 months should get most of the sediment out. But if you haven't drained it for a long time before, do the next three drainings 2 to 3 months apart.

If you first run the hot water out a faucet until cool, you need to wait a few hours for churned up sediment to settle down to give a better measure of how much to drain from the heater itself before the job is done.


 

Last edited by AllanJ; 06-17-24 at 06:20 AM.
  #18  
Old 06-19-24, 02:59 PM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
Wow, that's a long time to wait. Do you recommend not letting the hot water run cool then?
 
  #19  
Old 06-20-24, 04:31 AM
T
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 455
Received 9 Upvotes on 7 Posts
Also, remember that, once the tank is empty, I am turning the main back on for 30 seconds to a minute to try to agitate the sediment at the bottom of the tank.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: