Intermittent hot water + draining a water heater


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Old 03-04-21, 03:50 PM
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Intermittent hot water + draining a water heater

On a few occasions in the past, my wife and I both noticed that the shower water would not get real hot (if I recall correctly, this was usually in the morning where it was in the upper 20s or low 30s). It would be hot enough for a shower, but if you wanted it a wee bit hotter, even turning it on all the way wouldn't make it real hot (to the point where you couldn't be under the water).

Today (with the temp about 40 degrees outside), we both noticed it was just hot enough. This was in two separate showers. We had the heater installed in 2010 (and the date on it shows 2010). As I was looking for info about this issue, I came across some websites saying to drain a water heater twice a year (which seems excessive).

So, a few questions:

1. Is 10 years a good run, or is there something else I could look at to try to fix this problem?

2. Are water heaters supposed to be drained twice (or even once) a year? They talked about doing it to get rid of sediment to prevent the bottom from rusting.

3. If it needs to be drained, what's the process for doing this?

https://photos.app.goo.gl/cDSrT77omYniuqB18

Thanks,

Andy

 

Last edited by hikerguy; 03-04-21 at 04:05 PM.
  #2  
Old 03-04-21, 04:16 PM
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The short answer is YES and YES.
7 to 10 years is the average life of today's appliances. However a hot water tank used in a normal or typical fashion should get you at least 12 years or more. But when you get to 15 then consider or be ready for a new one.
Draining a gal or two once or twice a year is recommended. I don't do it and my tank last on average 15 to 20 years. Why? Because if the tank has those cheap plastic hose bibs then they will never seal right after a few times. And I'm not so sure you'll get anymore than maybe an extra year whether you do it or not. Better still is to us the PTV to make sure it's working. Snap it on and snap it off.
Others are going tell you to make sure you drain a gallon or two every 6 months like a religion. Note, your local water conditions will play a large part as to draining a gallon or two is necessary. Are you on municipal water? If so and it's very drinkable then maybe it's not so important. But if you have very hard water or Sulphur water or well water or sediment clogging up your sink ariators then do it.
 
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Old 03-04-21, 04:46 PM
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Thanks for the reply Norm. I thought they were talking about draining the WHOLE tank. I only need to drain 1-2 gallons??

Do I drain the water by releasing the pressure valve?? Is that what you're referring to ("cheap plastic hose bibs")? I did operate my valve tonight while I was out there just to see if it would release a little water (and it did).

We're on city water.


Any idea why sometimes it's barely hot enough for a shower, but other times we can crack past where it's comfortable to stand under?
 
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Old 03-04-21, 04:48 PM
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No not the relief valve to drain the one or two gal. That's just to test the relief valve.

It's the hose bib at the bottom that you would use to draw off one or two gals. It you have a metal one then go to it.
 
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Old 03-04-21, 04:56 PM
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Not sure why your not getting consistent hot water. Could be several reason. Maybe a broken dip tube. Some models were known for those to disintegrate. If the tube is broken or shortened then cold water is enter at the top and that's where you're drawing off water.

 

Last edited by Norm201; 03-04-21 at 05:00 PM. Reason: got mi ins and outs mixed up
  #6  
Old 03-05-21, 08:26 AM
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Flipping the pressure valve will drain some water and test that valve but will not accomplish the task of removing sediment.

Did inconsistently cool water for your shower occur when no one had been using hot water for a long time?

First thing in the morning try slowly turning up the temperature dial a few notches and immediately and slowly turn it back to where it was. If the water heater kicks on and stays running for more than 15 minutes you may have a sluggish thermostat (usually due to age) where the heater does not top off the water temperature after cooling down overnight.

Too much sediment accumulating in the tank can block the drain valve and make it more difficult to empty the tank for replacing when the time comes.

Nitpicking: Regarding the diagram above, a typical water heater does not operate with a water line with empty space above.within it. Any such space would be wasted space that could be used to hold additional hot water.
 

Last edited by AllanJ; 03-05-21 at 08:50 AM.
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Old 03-05-21, 11:31 AM
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So even though the drain valve/hose bib is at least a foot from the bottom, sediment can build up that high?

It's pretty intermittent that we notice the water isn't as hot as it could be. It's always hot enough for a shower, but just hot enough.

I'll give that suggestion a try this weekend and see if it kicks on.

 
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Old 03-05-21, 11:41 AM
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What temp setting do you have the tank set at?
Just after I installed my current tank about a year ago, I set the temp at normal. I also was not getting the hot water (and I like real hot water for a shower) as expected. My shower is on the second floor and has a lot of pipe to flow through. You'd be surprised how much heat loss takes place just traveling up the pipes. I set the tank temp up a little over normal. Major difference! I no longer have any problems with delivery of hot water at a sustained flow.
 
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Old 03-05-21, 05:08 PM
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It's set to A (whatever that means). I guess I could tweak it up some and see if that takes care of it. Take a look at the link below. One of the pics shows the dial:

https://photos.app.goo.gl/cDSrT77omYniuqB18
 
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Old 03-05-21, 05:42 PM
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The drain valve/bibb is (had better be) nearly at the tank bottom. Otherwise a lot of water will not come out of the tank when drained and the added weight of that water would be very inconvenient when it was time to replace the heater and get it out of the basement.

The burner and combustion chamber are under the tank.

 
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Old 03-05-21, 06:17 PM
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Set it to the B setting at least while the weather is cold. When it gets to be spring and summer set it back to A. If that does not give you consistent hot water then you have other problems.
 
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Old 03-05-21, 06:45 PM
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I meant why isn't it even lower/closer to the bottom? If there's sediment, it should be on the bottom, so I was thinking if the bib is even closer to the bottom, you'd have a better chance of the sediment flowing out when you drain the water. Maybe I'm overthinking this
 
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Old 03-05-21, 06:53 PM
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@Norm I decided to do this in steps and moved it between A and B. If that's not noticeable, I'll kick it up to B. Think I'll drain a few gallons this weekend and see what I see when I drain it. Thanks for the info.
 
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Old 03-06-21, 04:14 AM
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I meant why isn't it even lower/closer to the bottom?
It's about as low as they can get it. Just below the hose bib is the heater. Look at the diagram I posted in #5.

If you get rusty water or sediment or low flow then you know that your tank is at it's end of life. Most often a tank that needs replacement will show a leak. But not always.
Take some video or pics when you drain it load them up here.
Other possible problems as Allen J suggested is a sluggish thermostat, but that's very remote possibility.

Just a note...If you get to the point that you decide a new tank is in order, I suggest you stay away from the electronic ignition style and stick with a pilot light system.
 
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Old 03-06-21, 12:43 PM
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I meant why isn't it even lower/closer to the bottom?
The drain valve is at the bottom of the tank.
 
  #16  
Old 03-06-21, 05:53 PM
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Debris at bottom of water tanks promotes failure. Most manufacturers recommend flushing debris out of bottom of tanks several times a year. Just fully open bottom tank valve and flush a couple of gallons.

To reduce problem from debris install whole house water filter with clear plastic housing in feed to hot water tank and hydronic system. For ease of operation this type has 3 position, built in valve for Off, Filter and By-pass.

DH has municipal water here. Filter quickly gets brown from rust particles but only change element yearly.

https://www.lowes.com/pd/A-O-Smith-A...tem/1000576411
 

Last edited by doughess; 03-06-21 at 06:46 PM.
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Old 03-09-21, 11:54 AM
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So, I just drained at least a couple of gallons and saw that it had this "milky" look to it. Why would it have that appearance??? I saw no signs of rust. We're on city water. Pics are at the link below:

https://photos.app.goo.gl/cDSrT77omYniuqB18

Thanks,

Andy
 
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Old 03-09-21, 01:05 PM
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Hiker, Is this from the oxygenated water and does it clear up when it settles? If it does then it's normal. Or does the milky residue settle to the bottom and looks like "other" material besides water?
 
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Old 03-09-21, 03:24 PM
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@Norm

What do you mean by "oxygenated water"? I'll draw some more tomorrow and let it settle and report back how it looks after it's settled. Would 15 minutes be enough time to let it settle?
 
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Old 03-09-21, 04:07 PM
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"oxygenated water"
Lots of tiny air bubbles infused in the water (hydrogen and oxygen). Very common from refrigerator water dispensers. Common when with hot water also. They usually settle out within a minute or so. Perfectly harmless.

milky water from hot water tank hose bib - Google Search

If it stays cloudy then you may have a large deposits of suspended minerals. Do you see this from any other faucets?
 
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Old 03-09-21, 06:38 PM
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Debris in water-heaters tanks reduces service life. Rather than analizing debris, do regular flushing and eliminate cause of problem with whole house filter on line to tank.

If filter frequently cloggs then analyize debris for more appropriate type.

DH Post #16 showed a good filter with clear plastic body to see debris.

https://www.lowes.com/pd/A-O-Smith-A...tem/1000576411
 

Last edited by doughess; 03-09-21 at 08:05 PM.
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Old 03-10-21, 12:06 PM
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@Norm

I drained about a half gallon today and it did turn clear within a few minutes, so I guess nothing to worry about there (and yes, I had seen that at my faucet but never looked into the "why").

So, since I see no sediment, I guess I'm good to go? I did tweak up the thermostat a bit, but since it's an intermittent issue with the water being just hot enough for a shower, it's hard to say if that's a fix (but it probably is). I will plan on cranking it up just a bit more during the winter (although we don't get real harsh winters in the Raleigh/Durham area of NC).

 
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Old 03-10-21, 12:34 PM
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Good! About once every 3 or 4 months go ahead and drain out one or two gallons. No harm done.
 
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Old 03-11-21, 07:23 AM
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Thanks Norm!! That's a relief. I will definitely do that.

And thanks to the others who provided their insight as well.
 
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Old 03-12-21, 09:00 AM
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Periodic flushing only prolongs things.

Sediment is on-going issue that can be eliminated with whole house filter. Filte will also protect hydronic heating system from debis.

Installing whole house water filter is besolution those problems. See DH post #16
 
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Old 03-12-21, 09:15 AM
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I'm not saying that a whole house filter isn't any good. And I don't have one (nor have I ever felt the need for one), so I'm only talking from what I've heard from others. But I've heard those types of filters do minimal effectiveness vs cost to replace elements. And it's one more thing to add to the list of maintenance. And will they actually prolong the life of a hot water tank or any other appliance? Maybe, maybe not (perhaps a year more?) The cost is only on average $50. So that ain't bad. Of course as I mentioned earlier the quality of the water from the source is your determining factor. I look at this way, if the water is fit to drink, then it's fine for everything else. In my neck of the woods we have very high quality water coming from Lake Erie. Although a bit on the hard side, but not so bad that it has ever caused a problem with appliances. Very few people have water softeners here.
So my inclination, is if you think you need a whole house filter, don't go cheap, get a water softener and do it right. Just say'n.
 
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Old 03-13-21, 09:41 AM
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It is common on DIT.com to see posts link different issues often confusing problem. Issue here is debris in hot water tanks. Whole house filters eliminate debris.

Water softerners deals with a different issue, chemical/biologidal things that impact humans.

A common problem with municipal water is rust particles from water mains piping systerms. Some municpal systems also have mineral/hard water.

Whole house filters stops that debris from entering water heater. A $40 filter is low cost solution to one on-going problem. Softeners at $400 deal with different problem. Some places both are needed.

Whole house elements only needs to be changed when it lowers pressure. DHs cheap solutuion quickly gets rust colored but only change it every year or so. The $360 cost saving is another benifit.

https://www.lowes.com/pd/A-O-Smith-A...tem/1000576411

https://www.homedepot.com/b/Kitchen-...s/N-5yc1vZc6sb
 

Last edited by doughess; 03-13-21 at 10:17 AM.
 

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