Running out of Hot Water


Hi Folks -
This one has me stumped. When we bought this house 5 years ago, we quickly discovered it was easy to run out of hot water. I did the usual checks to see if the WH was connected correctly and also checked each plumbing fixture to see if a bad valve might be allowing the cold and hot to mix. I finally chalked it up to on old 40gal gas heater full of gunk and turned the temp up.
The heater finally died this summer so I replaced it with a 50gal unit with a larger burner. I set it at the recommended setting and figured all would be well. Lately, I find we are running out of hot water again. This morning, one shower emptied it. It is burning correctly, just full of cold water.
I bumped the temp up a bit but I really liked not burning my hands to a cinder with hot water. There has to be something causing this but I am stumped.
By the way, the old heater wasn't significantly heaver than the new one after I emptied it.
Any ideas?
Thanks!
PoD
--



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wrote:

Very weird, unless of course, you are taking real long showers. With 2 water heaters, and one of them brand new, it would seem your idea of the hot water somehow being cross connected with the cold is possible, though it would seem unlikely.
I'd perform the following quick and easy test. Let the system sit overnight. Then before any water is used, try opening just the cold faucets one at a time, and let it flow for a min. Go check the hot water pipe coming out of the WH a few feet from the unit. If it's hot, you'll know that somehow the hot and cold are interconnected.
I'd also measure the temp of the water coming out of the hot faucet. I think I have mine at about 130, which isn't real hot and I don't run out here with a 40 gal unit.
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wrote:

I think the key is:
.......Lately, I find we are running out of hot water again. This morning, one shower emptied it. ...........
and
...... I set it at the recommended setting and figured all would be well. .........
With a traditional tank style water heater there are couple of key variables.
tank size, water heater recovery rate, water heater temperature setting, hot water usage pattern & cold water feed temp
If the lack of hot water kinda went away last summer when you replaced the old 40 with a 50 (does the new one have a better recovery rate?) then I would guess that the problem came back because of a drop in cold water feed temp in your area.
Plus mfr's suggest a "low" setting for energy savings & to avoid liability wrt to scalding.
In my house the water heater is a small utility vault / basement....access is via a small closet door & a stairway.....the best I can do is a 40 but I made sure it had a better recovery rate than average. It's in SoCal, so even in the winter the cold water is usually about 60/65 at the coldest.
In colder areas of Ca (mountains) the cold water can get down to a bone chilling 40/45F.....so cold that using cold water alone can be a painful experience.
In addition as the cold water temp fails, one uses more hot water in a shower situation........ in "normal" shower situtation closer to 1 to 1 mix will give you a decent shower temp. When your cold water temp is COLD you wind up closer to a 2 to1 mix.
The solution most folks use is.....boost the water temp but that increases the risk of scalding & increases energy loss to the environment
The scald risk can be avoided with a tempering valve downstream of the water heater.
As if there are not enough things to think about ........with electric water heaters, there is a significant risk of Legionnaire's disease bacteria being able to thrive at water temp setting of 120F...... even boosting to 140F doesn't eliminate the risk. Gas / oil fired water heaters do not seem to have this problem.
cheers Bob.
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...

...
I can't find anything to substantiate the claim of electric vis a vis gas being any different and in fact, the only real substantive place that I saw it reported specifically states they cannot associate the observed correlation w/ causation owing to confounding factors in the study, not to mention it was a sample size of (3)...
"Although the Legionnaires' patients were more likely to have electric than gas hot-water heaters, the finding was confounded with water supply source -- that is, people with electric water heaters were also more likely to have non-municipal water in their homes. Therefore, we can't conclusively determine whether water heater type itself is associated with Legionnaires' disease risk." --http://researchnews.osu.edu/archive/legion.htm
I also found a brief quote from a report that indicates apparently a followup study did not find any statistical correlation on the electric water heater correlation. Here's a link and the blurb, but am not IEEE member so couldn't read whole thing on line. DA(very)QGS but didn't find the paper for further details.
"[h]ome electric water heaters were found not to be a. major risk factor for Legionnaires' disease in a 2-year. study conducted recently in Ohio. ..." -- ieeexplore.ieee.org/iel1/39/9905/00469560.pdf?arnumberF9560
And, OSHA specifically notes while possible to acquire LBD from inhaled mist in residential water systems, indications are the probabilities are much less than for commercial systems and more likely associated in the home w/ things such as whirlpools, etc.
"Q. Can my home water heater also be a source of LDB contamination?
A. Yes, but evidence indicates that smaller water systems such as those used in homes are not as likely to be infected with LDB as larger systems in workplaces and public buildings."
--http://www.osha.gov/dts/osta/otm/legionnaires/faq.html
So, I think you can stop worrying much over this one...
What I found does indicate that it pays to take care when doing maintenance on plumbing systems and especially if on non-municipal systems to be careful of general contamination issues in potable water supplies. That, of course, is true for a myriad of other issues most of which are more likely than LBD imo (coliform, etc., come to mind...)
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D-
here's the report I ran across
http://www.pulsus.com/infdis/15_01/leve_ed.htm
I should have posted with my earlier reply & I cannot vouch for the reliability of the report but it looked like it came from a refereed journal.
cheers Bob
btw I don't worry about LBD or scalding there are too many more important things closer to the top of that list
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--
Interesting. Unfortunately, there\'s no link to the study cited as the
source of the statistic they quote as providing the link between
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Paul of Dayton wrote:

    Isn't there supposed to be a tube that forces the cold water into the water heater so that it enters the bottom of the tank? If so, I wonder if they are installed?
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The other issue is what type of shower nozzle you have? Low flow ones provide less water but longer showers.
I would install a tempering valve, set the tank HOT thje tempering valve at the temp you prefer.
cold winter water temp is likely the source of the problem
how many BTUs is the new tank? 75,000 is prefered, many are 35,000 BTUs:( or less
the tempering valve effectively gives you more hot water and will fix your problem
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<snipped>
The shower nozzle is certainly something to consider. We had an old shower nozzle that would really pump the water out. It was great, but the hot water would start running out towards the end of the shower. No problems with a new nozzle.
-Felder
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snipped-for-privacy@aol.com wrote:

2nd on the tempering valve.
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That was my thought, your dip tube could be busted.
The fill for the WH is on the top, but so is the exit, so, to prevent the cold water coming in from going straight out without being heated, there is supposed to be a dip tube that brings the cold all the way to the bottom of the tank, so, if you looked at your hot water heaters cross section, the bottom would be cold and the top hot.
there was a class action suit a while ago where almost every water heater in production had faulty dip tubes that would disintegrate after a few years leaving the tank without a tube, I had plastic chunks coming out of my hot tap for a while till the tub was replaced. The old tube was only 3 inches long instead of the 3 feet it should have been.
since you say you have a new tank, its less likely that this is the case, but is it possible the tube is cracked or not attached correctly?
Dave
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Ken wrote:

IT's called a dip tube and it sounds like it was either never installed or recently broke free inside the tank (but that's unlikely on a new heater).
Low-flow shower heads will certainly help. I have one with a slider "bar" in the head that blocks off the flow of water so you can take a "navy shower". I rarely use that as I take what sailors call a "hollywood" shower. :-)
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My shower head has one to those sliders. I use it often. I like to turn the water off so I can apply soap without it getting washed away immediately.
I recently replaced a washer in the hot-water shower faucet. Now, every few days there's a big pressure drop and I have to clean the shower head because one or more pieces of that old broken washer got stuck in there (right behind the metal disk with holes in it).
--
Mark Lloyd
http://notstupid.laughingsquid.com
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On Thu, 01 Feb 2007 14:51:51 GMT, "Paul of Dayton"

This is an oil fired heater? SOmetime when you haven't run any water for a while, crank the nob all the way over to hot, and fill the bathtub until it starts running cold. How much water is that?
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3 things come to mind: Is there a tempering valve in your plumbing system? Is it possible that there is a dripping hot water faucet or maybe some kind of appliance valve (washer, dishwasher?) and, what kind of showerhead does your shower have? Have you tried a limited-flow showerhead?
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Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf.lonestar.org
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Thanks to everyone who answered. I have checked pipes and hot/cold where it isn't supposed to be. I think the sudden cold snap here in Ohio is the cause of my problem. As I mentioned in the 1st post, I have raised the temp a bit. It made a very noticeable change at the tap. I'll let everyone know if I still run out.
PoD

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I live in Ohio as well, and I had the same problem with my house when I first moved in. The wife liked to take Hollywood showers which depleted the hot water tank.
My fix was installing a high efficiency shower head. We tried a 2GPM shower head, but that frustrated the wife. I agreed with her as well - there simply was too little water coming out. So I set off to Home Depot and bought the 2.5GPM shower head. She reluctantly accepted that shower head and got used to it real quickly. Now we can take back to back showers without depleting our old 40 gallon tank.
Heat recovery is another factor. Hot water tanks vary in how quickly they recover. Older tanks may have a large amount of sediment in them which can reduce the amount of capacity. Flushing the tank once a year normally resolves this problem.
Best of luck!!!
wrote:

message
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snipped-for-privacy@yahoo.com wrote:

There is a company that manufactures shower heads compliant with government regulations.
The device consists of FOUR shower heads, each delivering no more than the Big Brother mandated 2 gallons per minute.
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Thanks for all the ideas, folks. The shower valve and head are quite new American Standard antique look-alikes. I raised the heater temp a notch which made a noticable change at the faucet. Didn't run out yesterday. I figure the sudden cold snap was the culprit.
I appreciate all the help!
PoD
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