As Murphy would have it, I had to visit the DMV today and try to figure out a plumbing problem. In doing so, I realized that good plumbers and good programmers have a lot in common.

This particular problem is like trying to debug code I didn't write and really never paid much attention to until it stopped working correctly. The symptom was a lack of hot water this morning. What I found is that the burner in the hot water tank was providing ample fire but the water just didn't seem to getting hot.

Noting that it was a Kenmore water heater, I called Sears. They transferred me to some local place where I got to discuss the finer points of water heaters with a rude, impatient, and dismissive woman. I left that conversation with two bits of data:

  1. The burner was running far too long not to heat the water. That must mean the hot water is going somewhere.
  2. She was a real bitch. I really wish I had paid attention to the name of the company she worked for.

I went around the house and checked each faucet to make sure none were letting any hot water out. Then I studied the water heater for a few more minutes to get a better idea of what could be going on.

There are 2 inputs and 2 outputs. One input is gas. It's used to heat the water and was functioning just fine. I adjusted the temperature control and proved that it also worked. The other input is cold water. It was clearly working as expected.

The two outputs are both for hot water. One is used for emergencies. It provides a way to let out hot water when something goes wrong. The second output is, of course, the hot water that goes to the rest of the house. And, strangely, it sounded as if water was flowing through it.

I noticed the valve on it and closed it. As I did, I distinctly heard the sound of the water's circulation being cut off.

Ah ha!

Hot water is flowing.

But where is it going? I have no fucking clue. Unless a neighbor has managed to tap into my hot water supply, I can't figure out where it's going. And that really bothers me.

Is it collecting in the walls? I find that hard to believe. I'd have seen evidence of it by now. Many gallons of water have flowed through the system.

The plumber I called is also stumped. I suspect that there's a leak in the wall behind the shower upstairs, but that's just a hunch. I managed to convince myself that I faintly heard water flowing back there a few times. He removed the face plate from the shower control but could find no evidence of a leak.


A next logical setup is to let someone rip into the tile and do a better job of trying to find the leak. But I'm not convinced it is the right step.

Like with debugging code, I want to understand more of what's going on. I'd really like a portable X-Ray system that could see into the walls and allow me to map out the plumbing. But I don't know where to get one of those.

There's a bug here somewhere. I'm convinced of that. The water should not be flowing out of the water heater unless I'm using the water.

Tomorrow I'll call another plumber or two and see what they think. Meanwhile, I'm manually enabling the hot water only when I need it. I suspect a really good plumber will have better debugging instincts on this one.

Update: I found the paperwork for the "Home Buyers Protection" plan that my realtor bought me via FATCO. There's still a bit over a month left on it. I'll be using that phone number in the morning.

Posted by jzawodn at January 19, 2005 07:14 PM

Reader Comments
# jr said:

Sadly, my experience with this sort of thing is that there can be a surprisingly small leak somewhere. They're also really, really good at hiding up until you notice water draining from your downstairs chandelier.

With me, it was an improperly welded anti-hammer trap that sprung a leak. It was not a pretty fix afterwards, but it was covered under my townhouse's warranty.

Good luck!

on January 19, 2005 07:48 PM
# chuqui said:

Does your place have a crawlspace? If so, go under it and see if you can find where the leak is exiting the house.

Also, this may seem like an obvious question, but have you or someone else punched things into walls recently? put up pictures, for instance?

Try to fine a friend with a stethoscope and use it to start listening behind walls near the plumbing, or where you might have piping (or try using the glass against the wall trick)

on January 19, 2005 08:30 PM
# Darryl said:

A good plummer is what you need. Or a plummer with good tools. I think you could pump air into the lines and listen for leaks or use a leak detector (listens for the sound of leaking air).

on January 19, 2005 08:32 PM
# Frank Horowitz said:

Just went through something similar myself. Turns out that some mineral in the local sand (thermally? electrochemically?) reacts with the copper pipe run just outside the brick walls in my house.

In Perth, this is such a common problem (in some suburbs) that there exist specialized "leak finding" plumbers, who basically have bought an acoustic microphone/headphone rig mounted like a vacuum cleaner to go around and listen for leaks.

I lucked out. By using my ears, I found the rough location where the _sound_ of running water was loudest. (The irony of this is that I sometimes do seismology professionally! :-) I didn't see anything for weeks, but eventually noticed that the sand between some bricks nearby was wet. Digging down under those bricks, a jet of hot water nearly hit me in the eye. There was a pinhole leak in the middle of a segment of pipe.

Don't know that this will help you in your situation, but strange things *do* happen with plumbing.

on January 19, 2005 09:36 PM
# dan said:

Also remember that plumbers like to tear things apart to fix the problem but they don't have to patch them back up, so keep this in mind when the plumber wants to tear apart the walls that YOU are going to have to put back together.

on January 20, 2005 03:45 AM
# Andy said:

Is it no hot water or a very short supply? I would think a leak big enough to keep a heater empty of any hot water would be significant - and noticable. It doesn't take much of a leak to make a big mess.

How old is the heater? If it is >10 years, it may be failing. Ten years is about the expected life span of most heaters. Sediment build-up, corrosion and such will affect the efficiency giving you a quick "run out" of hot water. The dip tube (brings cold water to the bottom of the tank) has corroded away, you would have hot water to start but it would go cool quickly as the tank refills from the top and is also being emptied from the top.

HowStuffWorks Hot Water Heaters

Good luck!

on January 20, 2005 08:38 AM
# chad said:

Ahhh you're lucky day! There's now a x-ray device for you!

on January 20, 2005 09:19 AM
# Scott Johnson said:

Home Buyer's Protection is always a good thing. :)

on January 20, 2005 09:31 AM
# Jake said:

Sounds like a problem I've been having too. Please keep us updated on the results of your plumbing forensics foray...

on January 20, 2005 09:44 AM
# Tom Norian said:

Sounds to me like you've got a faulty dip tube.

Now I went to a few sites to clarify my thoughts but for a while it was hard to prove that I wasn't imagining things. Then these site helped a bit:

Back in an earlier incarnation I owned 20 or so water heaters for 12 to 15 years.

A few comments....I don't think your conclusion is correct about the water runing.

I understand how you're leaping at it but its just not exactly like that. You're going to get that sound of turning off the water (or flow) in a correctly funtioning non leaking system. Why? I don't know exactly .... it could be a mater or relative pressure in the line or differential of hottwater versus cold water pressure? (warmer water taking up more space or something)

The "why" isn't all that important. And I'm pretty sure there is a mechanism or two in the tank reventing warm water in the tank from flowing up in a passing current into the cold water supply just like modern hosbits have anti siphon devices prenting changes in street water pressure to allow a sucking of contaminated water from your hose in the fishpond being sucked momentarily into the general city water system.

Those things sound far fetched to me but there a lots of valves that are forced to be put on during contruction projects under that public safter premise.

I suspect, from similar frustrating experience, that what you have happening is a worn out piece in your water heater.

I found that newer water heaters (like less than 10 or 15 years old) seemed to wear out quicker than the old ones....they don't build them like they used to ...they build them with "better" parts that supposedly increase saftey and efficiency but are more prone to wear out.

I think I remember a similar problem that I traced to some internal vinyl pipe within the water heater (I didn't see it, I just asked questions like you are).

There is also the possibilty that you've got a "self cleaning" water heater that has something similar where in order to make your heater "last longer" and to run more efficiently there is a internal pipe that rotates the water within.

Any rate, the two issues are similar. The cold water coming in is probably being sucked out rather than having a chance to fall to the bottom and be heated. Basically, in the name of better operations there is some sort of interchange area rather than the cold water being pushed right to the bottom and some vinyl tube within your tank either got plugged, ripped or worn.

A real nerd could take the thing apart and sent in for the propper piece...but of course you are talking skilled labor and a number of hours. Sort of like rebuilding a computer salvaging the box and power supply versus just buying a new one from dell.

Browse the on line do it your self sites but don't be fooled by the simplicity the big sites show...I imagine your model might have the dip tube or some other device in it.

Also, it might be the sediment...heres another link from a guy talking about blasts of it that come when water companies purge their main lines.

on January 20, 2005 02:19 PM
# Tom Norian said:

I'd also add that I'd find it really unusual for you to have a large enough leak to use up your hot water that you didn't have any other signs of. You'd hear the water leaking in the walls and crawlspaces I'd think and would see some water damage.

Now if you had hotwater pipes that were incased in concrete floor slabs that might be anothe issue. Other than for radiant floor heating (which often runs on a seperate system) I just can't imagine piping heated water back toward the cold ground on the way to a shower or sink.

You could test the leak theory by marking your water meter and coming back at the end of the day and looking to see if the hands moved (assuming everyone was out of the house and you didn't have the automatic sprinkers going). That wouldn't isolate the hot water system but you'd see other leaks too.

on January 20, 2005 02:40 PM
# Jeremy Zawodny said:

Tom: we checked the meter--you can see it moving.

on January 20, 2005 05:55 PM
# Dossy said:

I'd really like a portable X-Ray system that could see into the walls and allow me to map out the plumbing. But I don't know where to get one of those.

If you have a buddy in the local fire department, I hear they have some neat gadgetry that allows them to locate bodies in a fire based on what I can only imagine is some kind of infra-red spectrometer.

Find someone with access to one who could bring it over to your house (I don't suggest faking a fire call -- instead, try a case of beer) and walk around your home with it, looking for a heat signature inside a wall that looks like water ...

on January 21, 2005 10:22 AM
# Deadprogrammer said:

This totally reminded me of my favorite quote from "The Bug" by Ellen Ullman.

By the way, about seeing through walls - they sell these nice little fiberoptic scopes that you can just fish it through an outlet opening or a patchable small hole.

on January 22, 2005 11:59 AM
# vmasliah said:

Get infrared binoculars (night-vision) from an army surplus store or on Ebay. Shut off your main water valve to the house to give your water heater time to heat up the water in the tank. Turn the heater up to full hot. At night, turn the water back on to the house and walk around with the infrared specs to see if there are any heat signatures in weird places.
Check appliances that use hot water like the dishwasher which could be letting fresh water down the drain without you seeing it happen.

on June 17, 2005 02:45 PM
# Kay said:

Jeremy: By now you must have solved the problem. What was the outcome? I'm in the US, but I suspect water heaters are water heaters are water heaters no matter where you live.

You mentioned a "Home Buyers Protection" plan, but didn't say if it was for a new house or a resale of an older home. The age of the water heater is a pertinent fact. They tend to fail the day after the warranty expires.

You say, "The burner was running far too long not to heat the water. That must mean the hot water is going somewhere." Not necessarily; more likely the dip tube has rotten off.

You say, "we checked the meter--you can see it moving." The moving meter may be indicating a leaking toilet ... a very common problem.

A toilet doesn't use hot water, but you can hear the sound of running water in your house especially in the piping when one is leaking. Are you getting very high water bills? I vote for Tom Norian's diagnosis ... the dip tube has dropped off.

When hot water is used, it is drawn off the top of the tank; as cold water enters the tank to replace the hot water, it is delivered to the bottom of the tank through the 'dip tube'. But if the 'dip tube' drops off, which will happen, the cold water enters the tank at the top and immediately mixes with the hot water being drawn off the top.

In this case, you can start to take a shower and have plenty of hot water, but the water rapidly cools off as the cold water mixes with the hot in the top of the tank.

What was the solution?


on December 3, 2005 04:53 AM
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