# Could water heater be overheating and overflowing?



## bob_cntrctr (Jan 30, 2008)

Gentlemen,

I got a real head scratcher, so I'm starting to clutch at straws.

A duplex had just one water meter, until the water bills suddenly went crazy, so we put individual meters in each side. A week later, check 'em - what a surprise, one side shows three times the consumption of the other.

All fixtures shut off shows zero flow on the meter, so no leaks. Run the water on all fixtures on the other side, still no flow (hey, just in case, I've seen crazier).

So I'm staring the tenant in the eye asking what kind of water games her kids like to play after school before she gets home.

But just in case, I gotta cover all possibilities that might have to do with the plumbing. So I'm down to wondering...

...she says the electric water heater runs out of hot water a lot faster than reasonable. If she does the dishes and then takes a shower, she'll run out of hot water during the shower. It's a 40-gallon tank. The water that comes out of the taps is hot, very hot, but not boiling.

But I have to wonder the crazy theories - is it all possible for a water heater that appears to work fine to be doing something nuts like boiling the water overnight, and it's escaping out the pressure valve? 

We're talking hundreds of gallons a month here, not a few quarts. 

Problem is, the previous doofus that plumbed this place ran the overpressure outlet pipe down inside a wall to a drywell, so there'd be no traces if it was overflowing. I'll be fixing that now that I found it (enclosed in a wall, jeeeeez) - but I'm just curious if it's even a reasonable crazy theory to imagine happening.


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## KillerToiletSpider (May 27, 2007)

The new meters have built check valves in them and their is no longer a place for the water to expand other than the relief valve.


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## bob_cntrctr (Jan 30, 2008)

OK, fine. But ~600 gallons in a month of overlowed expansion?


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## mrmike (Dec 9, 2008)

bob_cntrctr said:


> Gentlemen,
> 
> I got a real head scratcher, so I'm starting to clutch at straws.
> 
> ...


Your theory is probably right on if you cannot see the open line of that pressure relief valve. This usually happens when the bottom element is shot on the heater. The top element is overheating the water to 210 deg setting off the relief valve. Alot of times you can hear it making noise. This will also be the reason for running out of hot water. Usually it is way hotter & you run out quick.
Another place to look for water escaping is the toilet Flappers. Best way to check them is to turn the water valve off to the toilet for a few hours & then check the level in the tank...............


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## KillerToiletSpider (May 27, 2007)

bob_cntrctr said:


> OK, fine. But ~600 gallons in a month of overlowed expansion?



I would think it would be more than that, the relief stays open and flowing for a few minutes after the pressure equalizes at 5 GPM minimum, so really all it takes is once a day with the valve open for four minutes to equal about that. It's something you might want to fix.


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## bob_cntrctr (Jan 30, 2008)

mrmike said:


> Your theory is probably right on if you cannot see the open line of that pressure relief valve. This usually happens when the bottom element is shot on the heater. The top element is overheating the water to 210 deg setting off the relief valve. Alot of times you can hear it making noise. This will also be the reason for running out of hot water. Usually it is way hotter & you run out quick.
> Another place to look for water escaping is the toilet Flappers. Best way to check them is to turn the water valve off to the toilet for a few hours & then check the level in the tank...............


Hmmm . . it is an older tank. And when it's heating it's pretty loud - like when you first turn on the coffee pot. Already checked all the fixtures like the toilets.


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## bob_cntrctr (Jan 30, 2008)

KillerToiletSpider said:


> I would think it would be more than that, the relief stays open and flowing for a few minutes after the pressure equalizes at 5 GPM minimum, so really all it takes is once a day with the valve open for four minutes to equal about that. It's something you might want to fix.


Ya, wait minute - I dropped a zero and a 2 from my calculations - it's not 600 gallons, it's 12,000. 120 cubic meters more than usual over 2 months. 60 m3/month x 200 gals/m3 = 12,000 gallons. Down a drywell, thorugh a pressure relief valve.

No, it can't be...


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## bob_cntrctr (Jan 30, 2008)

mrmike said:


> ...This usually happens when the bottom element is shot on the heater. The top element is overheating the water to 210 deg setting off the relief valve. ...............


Gets me thinking - and electric in all this? She's had higher than expected electric bills since about the same time she's been complaining about the how water running out. But that coincided with the arrival of the cold weather so we figured it was the electric baseboard heaters. I suppose a water heater in this condition will suck up the KW's?


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## KillerToiletSpider (May 27, 2007)

bob_cntrctr said:


> Ya, wait minute - I dropped a zero and a 2 from my calculations - it's not 600 gallons, it's 12,000. 120 cubic meters more than usual over 2 months. 60 m3/month x 200 gals/m3 = 12,000 gallons. Down a drywell, thorugh a pressure relief valve.
> 
> No, it can't be...


Those numbers are closer to what I would expect to see from a relief valve dumping if it is dumping every 5 hours, and a releif valve is basically designed as a one time valve, to be replaced if it is ever forced to activate.

You might want to address the problem instead of continuing to question it.


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## Driftwood (Feb 15, 2004)

*Can't see it in a drywell?????*

W.H. T.P. valve is suppose to dump outdoors ,no less than 6" and no more than 24" above the ground. Inside indirect waste to a trapped floor drain is OK
Sounds like this pipe is set under gravel! If so It's a violation!


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## DuMass (Feb 6, 2008)

If the water heater was made within the last several decades and was overheating, the thermo-disc on the upper thermostat should have tripped at 190-degrees disabling any further heating until being manually reset, normally well before the 210-degree TP valve opens. However, a slow leaking TP valve as mentioned is still a possibility.

I would probably recheck the chains, flush levers and flappers in the toilets as someone else mentioned. A chain that is too long and occasionally rests under the flapper or a flush lever that sticks and partially raises the flapper every so often can really add up to a lot of wasted water when someone flushes the toilet on the way out the door and heads off to an 8-hour workday. 
If the toilets have anti-sweat mixing valves on them then hot water would also be wasted.


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## mrmike (Dec 9, 2008)

MAke sure you check out the water heater as I stated. I haven't found thermo-disc popped out very often. That relief valve is designed to release the water as it is overheated & thermal expansion & usually does before it trips out. I have seen this many times,,,,


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## bob_cntrctr (Jan 30, 2008)

OK, everything is pointing to this old heater. It's probably at least 20 years old anyway. And the thing of running out of water, almost assuredly a blown lower heater element. So rather than fiddle around with checking the overpressure outlet with a bucket and so on and so on, I'm just going down there tomorrow to put in a new one. At least it won't be a question mark anymore.

Damn, another wall to rip open.

Thanks, everyone.


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## Driftwood (Feb 15, 2004)

Do your self a favor. go to a plumbing supply and pick up a BRADFORD WHITE


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## boman47k (Oct 13, 2006)

Just curious here. What if the dip tube is eroded/eaten up and the water is feeding in closer to the top? Would the cold water feeding close enough to the top of the already heated water not cause a reduction in the time it takes to run our of hot water and make the top stat work more?

Hmm, I guess that does not explain water loss though.


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## jcalvin (Feb 1, 2008)

I'm not a plumber but I would check the thermostat on the WH. I had one on my house one time that went bad. The t-stat never told the elements to quit heating and the heated water would cause such pressure the pop off valve kicked in. The part that makes me question this is that it is loud. I was able to hear mine in the basement directly under where I was sitting over the tv. If the WH is somewhat remotely located, I guess I could understand if they couldn't hear it. But is would have to be through several insulated walls to mask the sound.


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## jayson22 (Feb 7, 2009)

I would always recommend changing a T & P valve on a hot water heater if in doubt. As for the water loss, most common areas of water loss are from running toilets and dripping hosebibs.


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## TimelessQuality (Sep 23, 2007)

She runs the 40 gal out takin' a shower? 

Maybe crank the temp up (as long as they don't have children).

I bet if you had her swap units w/the neighbors, the water bill would follow.


Oh yeah, you need a new water heater...


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## bob_cntrctr (Jan 30, 2008)

UPDATE UPDATE UPDATE 

So, as planned, I went and rippedopen the wall. The last damn fool to plumb this place enclosed the WH inside a cavity in the wall.

Remember, what started all this was an outrageous water bill with 130 cubic meters more consumption than usual (two months). Then when we installed separate water meters (on this duplex), a few days showed one apartment using 2 to 3 times as much water as the other, so we thought - aha! - the problem must be over here. And when the tenant reported running out of hot water, a high electric bill, and someone said there was a decades old WH in the wall, everything pointed to that being the culprit.

Anyway - big surprise - it's practically a brand new WH, just a few years old, a quality brand name, in perfect condition. I had ben told it was a 20 -30 year old tank in there. Ran it to cold then watched the electrical meter - sucking exactly the same juice as the WH in the apartment beside it. Heats for an hour, then shuts off just fine. No overflow. No signs of there ever having been an overflow. There's nothing wrong with this tank, and it's not the source of all the problems.

But, it is just a little 22 gallon tank. So guess why she runs out of hot water. One mystery solved.

With the separate water meters installed for 10 days now, we were able to do some comparison and calculations. Yes, one apt is using thwo to htree times as much water as the other. But at this rate, they're on track to consume just ~20% more than the basic amount included in the monthly basic fee. That's maybe an extra 2 cubic meters per month. Nowwhere near enough consumption to generate the 130 m3. At this rate, the other apt, then, is conmsuming a fraction of what is considered normal. It's not that the on is comsuming so much, it's that the other is consuming so little that makes their relative consumption appear so different.

And the electricity - it's electric baseboard heaters throughout, and the bills the tenat's complaining about are for December, January, February - they didn't figure heating your home should cost much more than running light bulbs.
Sooooooooo - water consumption is normal. It's a small tank that's working perfectly. Electricty consumption is normal.
The only remaining mystery is the huge water bill. Another bill came in - consumptin up to the day the new meters were put in, exactly two more months after the previous bill. Still waaaaay high, but less than the previous one. If that much water were leaking in a wall fo four months, the drywall would be falling off the studs. And it'd be the same, or getting worse, not better, and someone's meter would be showing it.

No, apparently someone really did pour 130 m3 of water down the drain. That's ~30,000 gallons. A tap full open = ~ 5gpm. so even at just 1 gpm, that's 30,000 minutes =~ 500 hours, or ~ 3 weeks day and night. Someone has left their tap running. I'm guessing it's the guy in the other apt whose life, from what I've seen, appears to basically consist of getting drunk and passing out.

Just goes to show how information can be misleading sometimes.

Anyway - thanks everyone who tried to help.


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