Home repair crew help needed; Water heater troubles

[klarowe]

My house has a 40gallon water heater. For the past few months (yea, I had other shit to deal with so this was a back burner) I've had some problems with the "lasting abilities" of the hot water. I take some quick 5-10 minute showers and I found that I was constantly having to turn the water temp hotter and hotter just to maintain a decent water temp. And at the end of 10 minutes the dial (single water valve) would be all the way to hot and the water would barely be luke warm. Wifey was having the same issue but would basically be taking a cold shower since hers took longer.

I thought this was odd so I decided to do a test tonight. I turned the dial straight to full hot and turned the water on with the plug in the drain of the tub. I let the water go until it was completely cold coming out of the faucet... so that I knew I had used up every possible stitch of hot water. I then took a 5 gallon bucket (not precision,  but it did the trick) and started emptying the tub into the toilet so I could get a rough measurement of how much hot water I had. I came up with an absolute max of 32 gallons.

Now this has me a little confused. I would say bad water heater, but usually when a water heater goes you just don't have hot water. But the water starts off EXTREMELY hot... almost scolding but then just drops temp drastically as it runs. I understand that the heater doesn't heat the entire tank of water so there won't be 40 gallons of scolding hot water, but I should be getting more out of the tank than I am... I would think.

Any suggestions? The water tank is natural gas, 40 gallon. Its an older tank, but visually is in good shape... no extensive rusting, build-up, etc.

[Kavik]

I'm no expert with those things....but as a first step, have you tried draining some water from the drain valve at the bottom of the tank?  I wonder how much crud there might be built up inside the tank, regardless of how good the outside looks.  I would hope not enough to make up the 8 gallon difference, but maybe enough to be making it not heat as efficiently, slowing down how quickly it can heat new water as the hot water is used up

[madlife]

I'm no expert with those things....but as a first step, have you tried draining some water from the drain valve at the bottom of the tank?  I wonder how much crud there might be built up inside the tank, regardless of how good the outside looks.  I would hope not enough to make up the 8 gallon difference, but maybe enough to be making it not heat as efficiently, slowing down how quickly it can heat new water as the hot water is used up

Same issue here,  and this was my dad's suggestion.   I too have been busy with other shit

[klarowe]

I ran the faucet until there was no hot water left then went down and opened the drain. The water coming out was just as cold / luke warm as what was coming out of the faucet. I did that to check if maybe the internal pipe that picks the water from the bottom of the tank had gone bad... but that seems good. I also watched for sediment and I got about a double shot's worth of brownish water, but that was it. I have a feeling the burner / heating element is going and is not heating the entire tank. I'll probably end up replacing it now that I'll have some tax return money... otherwise with my luck I'll spend my tax return and then next week the tank will completely go and I'll be screwed. So I guess the STI gets no love this time...

[BradleyGT]

couple things here,

water heaters work on capacity/recovery. so just for an example, at 4gpm (average peak usage) with a 40 gal tank, just with capacity you should recieve hot water for 10mins. at whatever temperature the tstat on the tank is allowing. your shower head is somewhere between <1gpm to 3gpm. pretty wide range as far as water is concerned, but really not relavent to the point. the recovery rate is what really is going to help you decide whats going on unless you have complete failure.

if you are still getting hot water for at least a small amount of time, i feel you are on the right track with blaming your burner. however, just draining the tank will not allow everything that may be affecting the ability of the tank to drain out. a little bit of rusty/brownish water settled to the bottom is pretty normal. basing the thought completely on what you've said, i don't think this is your issue, simply because you got about 40gal. of hot water out in the span of about 10 mins. before it went cold.

i would say that you have a thermostat problem. usually the t-stat is incorporated into the gas valve. you may just have to replace that valve, and you're golden.

then again, i would not suggest you do this on your own.

cliff's notes: explore the possibilty of calling a contractor to trouble shoot the tank before replacing the entire unit, might save you some money.

[klarowe]

Part of me would like to just fix this and save money... but the other part of me says replace it because of its age (I believe its over 10years old). I am confident in my abilities to repair it if need be... i'm comfortable working with gas (installed my own boiler in the house and forced air furnace in my garage)

[BradleyGT]

considering the age of the tank i would agree with you. 10-12 years is usually the working life of a water heater. to add to that, most parts for tanks that age are phased out and are either not available or jacked in price due to reduced production. and don't take my suggestion to call a pro as a shot, it's usually a lot of common sense to do a basic install, i just don't suggest it unless you have experience.

[hydrochloric]

It may be different with gas-fired water heaters, but 10 years is a bit less than half as long as our electric one has been running.

[RedRex]

If you have hard water, and no softener before the tank, you should drain a few gals. or so monthly, to reduce sediment. (I have well water with some iron in it, and this works well for me.)

You may find that the bottom of the tank is all sediment.  Without maintenance, 10 yrs. is a long time. 

In my last house, the tank started to leak. When I replaced it I could barely move it with a hand truck. It was 1/2 full with a disgusting pinkish sediment.

[klarowe]

I drained out about a gallon or 2 and only got about 1/2 a cup of sediment... the rest came out perfectly clear.

[Garufi518]

your luck is shot....you need to parts for the sti lets get the important stuff first

[klarowe]

yea... i wish. Hopefully this will be the 2nd to last big purchase for the house for a bit (still gotta do the porch roof this spring). Then maybe I can get fun stuff.