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-   -   Why doesn't my hot water last? (http://www.diychatroom.com/f7/why-doesnt-my-hot-water-last-488/)

MWM 03-30-2005 08:25 AM

Why doesn't my hot water last?
 
Hi, all...first-time homeowner here.

I have an issue that even my plumbler can't seem to figure out. My fiance' and I live alone in a 3 BR house with only 1 full bath and 3 sinks total (1 bath, 1 powder room, and 1 kitchen). We have a 40 gallon gas-fired hot water heater. The previous owner performed some major rennovations on the house, including changing from oil to gas heat, completely tearing down and replacing the full bath, adding the powder room, and gutting the kitchen. I'm sure some plumbing work was involved in the rennovating, although I'm not sure if he contracted the work out or did it himself.

We're experiencing some strange behavior in regards to how long our hot water lasts. It seems that first thing in the morning, after we've been asleep for 8 hours, the first person in the shower can't seem to get more than 7 minutes or so of hot water before things go tepid. After the unit has a chance to recycle itself, the next person seems to do alright, although we usually find ourselves cranking the hot side up towards the end of the shower. Neither one of us are marathon bathers (10 minutes tops). Sometimes we can't get any hot water at all. On two occassions my bride-to-be has come home from work and tried to draw a bath (again, this is after neither one of us was home all day), and couldn't get the tub to fill with ANY hot water. So it's erratic to say the least, and short-lived on its best days.

My plumber has come out twice and can't figure out for the life of him what the problem is. Of course, he's coming out at 8:30 in the morning, after we've both had showers and the unit has reset itself, so he's not seeing any of the problems we're experiencing. He says that a 40-gallon tank should drain in 20-25 minutes on FULL DRAW (130 degree water...which would scald and burn the skin in about 10 seconds...neither one of us likes it THAT hot). His only suggestion was to replace the water heater, but considering how the problem seems to be isolated to times where the hot water has gone unused for a period of time (in the mornings after we've been asleep or in the evenings right after we come home from work), I'm wondering if there might be something wrong with my plumbing.

Any ideas of what I should do/try before I shell out the money to replace/upgrade the unit (we're thinking of going to a 50 gallon)? Thanks in advance

Tomm 03-30-2005 08:35 PM

MWM; Usually the first thing to do in this case is to flush the mineral sediments from the bottom of the tank. It is not hard to do, BUT you can screw things up if you don't do it right. First though, is why they effect your water temperature in the way you discribed. These sediments are crystal like and they distort and store heat in a way that fools your thermostat into "thinking" it is doing a good job. That being said...all it takes to flush the sediments is a good garden hose. Attatch the hose to the fitting at the bottom of the tank, and run it to your bathtub, this is so you can monitor the discharge to be sure you are removing the sediments, and how much is being removed, and when the water is flowing clear. Above all...do not turn on any hot water valves while flushing, especially a high flow line like your bath tub, ..that will stir the sediments up too much and plug the valve, and believe me, you don't want to do that.

You should notice an improvement after doing this, BUT...you may have to repeat the proceedure again, after a day or two of normal water use, or maybe more than once to get real good service restored. If after two or three flushes you don't get a marked improvement, it's time to check for flow restriction in the lines closest to the water heater. If there is no major restrictions, then I'm afraid it's time for a new water heater.

Teetorbilt 03-30-2005 10:17 PM

I am leaning towards a 'floater'. This could be some scale that has become loose in the cold water service to the heater. When the demand is there, it will be pulled by the flow to the nearest obstruction. This could be an elbo or valve.

ryaniniowa 04-04-2005 04:03 PM

Hi all: How old is your heater? I ask because in the late 90's the manufacturers were using a really cheap crappy dip tube that would fall apart after a few years. Instead of the cold water going all the way to the bottom of the tank the cold and hot would mix at the top and you would run out very fast. The bottom of the tank would be hot but you got cold water out of it. Anyway, just something else to check.

Tomm 04-04-2005 10:06 PM

Thanks for the insight Ryan, it's always a major benifit to hear about particulars such as that, I'm not sure there is another vinue to pick up this type of valuable information than this sight. I for one really appreciate it and look forward to more if it is available.

Teetorbilt 04-04-2005 10:23 PM

Tomm, one of the things that make this site different is that it is tied into a contractors site. Much of the info that is available here come from people who do it for a living.
Enjoy and tell your friends.

MWM 04-05-2005 08:58 AM

Quote:

Originally Posted by ryaniniowa
Hi all: How old is your heater? I ask because in the late 90's the manufacturers were using a really cheap crappy dip tube that would fall apart after a few years. Instead of the cold water going all the way to the bottom of the tank the cold and hot would mix at the top and you would run out very fast. The bottom of the tank would be hot but you got cold water out of it. Anyway, just something else to check.

Replacing the dip tube was the first thing the plumber I called did when he came to service the unit. We couldn't determine the age of the heater, as there were no markings on the cylinder we could decipher as a manufacturing date. My guess is it's about 6 years old. It's a 40 gallon Bradford White.

kidwelli1 05-11-2015 06:30 PM

MWM - can you please tell me what solved your issue? My girlfriend and I are experiencing the SAME EXACT issue with our home. 3 plumbers and still no fix :(
Anything you can tell me would be HUGELY helpful!!
Thank you!!!

Ghostmaker 05-11-2015 06:46 PM

Replace the cold water dip tube on your hot water tank. It has either dissolved or broke on its way down to the bottom.

Akpsdvan 05-11-2015 07:38 PM

I would go with that dip tube..... been there seen it and replaced it because on the Elect one with the elements out of the way one could see the old one laying in the tank... just put another in and life was good again...

kidwelli1 05-12-2015 05:46 PM

Sorry I didn't elaborate further in my initial post... We have actually replaced the entire water heater already, and are still experiencing the issue. We installed a 50 gallon gas Rheem (38,000 btu). One plumber suggested that the flame looked small and a minimum of 40,000 btu's are required to make the hot water last. He suggested that I ask Rheem what my options are to increase the btu's, but I haven't pursued that avenue yet. Does this sound like the right thing to do? Again, our issue is that our hot water only lasts about 5-7 minutes before becoming luke warm.
Thanks in advance for your advice!

TheEplumber 05-12-2015 06:45 PM

Do you have any single handle faucets? There is a possibility the cartridge is bad and is allowing cold water to blend across to the hot and affecting the house system

nanuk 05-12-2015 06:51 PM

Whole house humidifiers waste a good amount of hot water. Mine does :(
Is this relevant?

MTN REMODEL LLC 05-12-2015 06:51 PM

Quote:

Originally Posted by ryaniniowa (Post 2225)
Hi all: How old is your heater? I ask because in the late 90's the manufacturers were using a really cheap crappy dip tube that would fall apart after a few years. Instead of the cold water going all the way to the bottom of the tank the cold and hot would mix at the top and you would run out very fast. The bottom of the tank would be hot but you got cold water out of it. Anyway, just something else to check.

Sorry to digress.... but good lookin pup....:thumbsup::)

MTN REMODEL LLC 05-12-2015 07:04 PM

If I did not miss a post, seems you have only addressed/discussed your SHOWER.

Test your hot water supply at the kitchen sink or another bath. If you have good hot water supply at an alternative site, you can outrule the WH/dip tube/temp regulator.

Or, buy a $20 infrared sensor, and measure the hot water supply out of the W/H.

It's either a W/H issue, or a supply issue in your plumbing/faucets.

(I seem to run into alot of dip tube problems, but they don't explain your lady not having hot water for her bath after she comes home from work with no prior draw on the hot water.)

PS: ( Are you two sure that you are not just spending alot of time and hot water together in the shower...:wink:)


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