Mystery hot water running

[Tucker]

I have a gas hot water heater that, for the last week, has been constantly trying to heat the water (with a normal flame), but I only get warm water throughout the house. There is a slight sound of running water that is loudest behind the shower/tub on the second floor. There is no evidence of water on the ceiling below the shower or anywhere else. When I turn off the water supply to the tank, the sound slowly stops, and the water quickly heats up to normal temp. Each time I need hot water, I must turn on the tank supply, and then off again when finished. The shower-tub control is a Moen 2739A single handle control. Yesterday I replaced the cartridge, thinking that there might be something that was related (It also had a slight drip that is still there with the new cartridge --except when I turn off the water supply to the heater).

Before I tear into the wall behind the tub, is there any other possibility that there is hot water crossing through the Moen apparatus into the cold water pipes? The heater is not dumping through the relief valve, but it is going somewhere after it leaves the tank output line??


If the picture of the Moen parts does not show up, go to this Moen URL and click on "STEP 1: View Illustrated Parts Diagram to find the part you need ".
http://www.moen.com/buymoen/buyparts/parts.cfm?sku_Refno=307685&CFID=2255553&CFTOKEN=42284e43dfdde777-9E40A57B-9BA8-142E-C2D796DD170970E8

[BAPlumber]

sounds like a leak in the hot water piping somewhere in the house. the sound of the leak could transmit itself quite a ways. Is there a bathroom directly below the upstairs bath? is there a crawl space?

[cwhyu2]

This is not a pressure balanance faucet.You could have a broken dip tube
in your w/h a by pass mixes hot with cold.How old is your w/h?

[Tucker]

Brent, the 2nd floor bathroom where I hear the sound the loudest is over my garage. I have had some unrelated leaks in the past, and it shows up as a stain on the ceiling sheetrock (nothing yet). There is no other plumbing nearby. There is no useable crawlspace, other than the space between ceiling trusses over the garage. The hot water loss must be substantial since the heater cannot get past minimal warm--about 120 degrees F.

[Tucker]

CWHYU2, the heater is a Sears Kenmore 8 with a "Roto Swirl" dip tube. I don't see anything to allow water to escape without making a puddle somewhere. It about 6 years old (WAG).

[jimbo]

Do you have a recirculating pump on the hot water system? The hot/cold crossover really does not happen unless you have a pump.

The other possibility is an underslab leak, if you are on a slab. Check for warm spots on the floor anywhere on the first floor.

[BAPlumber]

You probably have a leak underground. Need to find a plumber who does underground leak detection or a leak detection company.

[cwhyu2]

check this out .Is your washing machine operating properly.
sometimes if the solinoid valve becomes stuck it can make sound like water
running through out the whole house.This will cause a by pass.
With out being there its hard to diagnose.

[BAPlumber]

check this out .Is your washing machine operating properly.
sometimes if the solinoid valve becomes stuck it can make sound like water
running through out the whole house.This will cause a by pass.
With out being there its hard to diagnose.

from what's been said it doesn't sound like this problem has anything to do with a mixing valve or bypass. the hot water is getting out of the system somehow. slab leak.

[Tucker]

No recirculating pump & washing machine is ok. I will now spend the day checking for hot spots in slab. Over time, maybe plants/weeds will start to grow where they didn't before. Is it possible for there to be a higher pressure in the hot water line than in the cold line (due to expansion heating of the water and an anti_back flow check valve)? If so, then some defect in the Moen valve cartridge (o rings or the 2 big rubber gaskets) might allow hot water to be pushed back into the cold line??!!

[master plumber mark]

If the washing machine is not doing a bypass thing

then most likely you got a slab leak and that is nothing

but fun fun fun....

I suggest before you start to tear the floors up,
you might want to consider seeing if you can re-run the water lines up out of the concrete for both hot and cold..

it sounds like a lot more work but the hot lin can get you again anytime again.


becasue once you have one slab leak usually you can
expect another one ....they usually come in 3


weigh your options carefully before you get out the
jackhammer...and pull back the living room carpet.

[Terry]

I'm throwing in a vote for leak under the slab.

[geniescience]

how much time does it take, after you turn the water supply to the heater back on, for the temperature of the hot water pipe coming out of the heater to feel only 120 degrees? Instead of real hot.

David

[cwhyu2]

from what's been said it doesn't sound like this problem has anything to do with a mixing valve or bypass. the hot water is getting out of the system somehow. slab leak.
I did not know it was a slab.But if it is aleak underground on hot water side
then the pressure and volume may be lower on the hot side.If pressure and
volume are the same on hot and cold.Then I think dip tube.Regardless of age of w/h.

[Tucker]

When I turn the water supply back on, there is a 5 second rush of water to refill the tank. At this point, the water was normal hot. Running the water in the sink for 4-5 minutes brought the temp down to about 120 degrees. If there is a leak in the slab, is there a diy test to confirm it other than feeling the concrete for warmth? This is Corpus Christi, Texas, and everything is hot!


BTW, in a somewhat related subject, When I attempted to replace the cartridge yesterday, it was stuck, as advertised (not). In reading all the posts here and elsewhere, I saw a picture of the tool that is made to remove these cartridges. Years ago, I bought a box of plumbing gadgets at a garage sale for pennies, and lo--there was this odd tool and I had no clue of it's purpose. It was the extractor! See why I ignore my bride's pleas to "throw out all the things that you never use in the garage"? Anyway, most posts indicated that it only removed the inner part of the cartridge and messed up the brass outer part. I put a big washer between the extractor and the Brass housing to keep from bending the housing as I tightened the nut. Also, I didn't bottom out the screw that goes into the valve stem. I didn't move the bar handle, since the tabs that it is meant to turn were long gone from the cartridge. It came out in one piece. The washer has to have an inner hole that is big enough to allow the cartridge to pass through it as we tighten the outer nut (see picture).

[cwhyu2]

I love these things. they work good.As far as your hot water problem Iwish
there more I could do.Keep listening.

[master plumber mark]

you can payu someone to come out and find the hot spot....


Its pretty easy to know wether you have a slab leak or not...

all you have to do is turn off your hot water at the water heater and wait about 10 - 15 minutes ...
dont turn on anything.

then after 15 minutes simply go to your kitchen and turn on the hot water...

if their is no leak in the slab, you should still have full
pressure in that water line. for a minute or so it should come
out in full force till you exaust the pressure in the line...


if you turn on the kit faucet and it barely trickles out a stream at all,
(like when I go to the bathroom)

then that means it escaped through the hole under the concrete slab.

[jimbo]

One obvious thing I forgot to mention....can you go look at your water meter? With all the taps in the house off ( but that WH shutoff open) the meter dial should not move at all.

[Tucker]

I will check the water meter in the morning before anyone uses water. Thanks to all for ideas!

[toolaholic]

I'm reading every post saying check THE water METER
We have an Eichler home with radiant heat. found the 3/8" copper tubes with my Raytek raynger st laser heat gun.Will find hot spots in slab. I was core drilling in Mine

[Tucker]

Good idea--Harbor Freight has a non contact thermometer on sale until tomorrow for 40$, minus a 15% coupon. It should work for these purposes if my meter has moved in the morning!

[geniescience]

When I turn the water supply back on, there is a 5 second rush of water to refill the tank. At this point, the water was normal hot. Running the water in the sink for 4-5 minutes brought the temp down to about 120 degrees. If there is a leak in the slab ....no good. What will tell you something real is how much time it takes for the HW heater temperature to go down WITHOUT you turning on any taps, as this will be one real good indicator that there is a leak (under slab or elsewere). Another post from someone else also pointed out that when you turn off the main supply and wait fifteen minutes, the kitchen tap either has a lot of water to let out or a little, depending... That is the same idea, the same type of information confirming or not whether water is leaving your system. And whether the meter is showing any flow.

The HW heater may give you a little more clues about the problem, if it is something really unusual.

david

[hj]

You DO have an underfloor leak. You DO NOT have a water heater, Moen valve, or anything else problem. Call your homeowner's insurance company to see if there is coverage for this, (some require that the water be coming throught the floor causing damage first), then a plumber, and he may call a leak locator if the spot is not self evident.

[Tucker]

This morning, I heard the same sound of water running behind the upstairs shower wall and the tub spigot still had a slight drip (about 1 per 3 seconds). The water meter showed water usage, as expected. I went through a series of shutting off the tank supply, opening faucets throughout the house, turning the supply on and off, etc. There was a sudden rush of air and rusty water, and then everything was back to pre-problem normal! No sound of running water, no drip at the Moen tub spigot, and the meter is no longer moving. If there was a leak in the slab pipes, it got plugged by the rust. The sound of water movement was always loudest around the 2nd floor shower/tub walls, so some mysteries go unsolved. I never turned the water on to flush out the Moen guts while the cartridge was out, so maybe there was something there distorting one of the rubber pads or O-rings? The valve works better/easier now than it has since 1985 when we built the house. Hope it stays that way. The power of prayer!
Thanks to all for the wisdom -- I am a lot smarter now. John

[geniescience]

http://www.dvdclassicscorner.net/images/AliceinWonderland-masterpieceedition.jpg

curiouser and curiouser. Alice in Wonderland stuff.

I figured that this being a noise heard on the second floor, you might have a leak that was not necessarily in the slab, and that the water might not be finding its way down to the garage ceiling, at least not now.

No way is anyone going to tell you to go back to normal and assume the problem has gone away. The problem is not solved, not repaired, not improved, no way. For the time being, water flow is down to next-to-nothing is the way I see it.

David

[Gary Slusser]

I don't recall if it was mentioned as to where the heater is but how about a temp/pressure relief valve leaking when the heater is heating water due to using hot water?

Air is not a good sign, especially when you have the water to the heater shut off.... sounds like the heater is overheating the water, creating DO to come out of solution or the formation of steam. And when you got the flow of air, it scrubbed the plumbing clean of rust sediment build up in the pipes which is normal.

So I think you still have the problem but the symptoms went away for awhile.

[Tucker]

My computer was down all day. The air got into the line when I had the supply turned off and opened spigots on both floors to drain the pipes. I closed the spigots, turned on the supply, and then opened a spigot. That is when the rush of air and rusty water shot out, and the problem disappeared.!?!? It could be that the blast cleared some obstruction in the valve and flushed it out. The water was not unusually hot. I never saw any indication that the overtemp/pressure relief valve had opened even though the sound of running water was present upstairs. Enough water was leaving the tank to cause a major puddle somewhere if there was a leak
(except if it was in the slab). I should have looked in the outside sewer trap to see if water was running through it, but how would it get there directly from a supply pipe? Is there some construction code that requires a relief valve that dumps into the sewer line under special conditions? If so, it could have been stuck open. No toilet, sink or washer was running. So far, all is normal. I hesitate to go on a trip without shutting off the hot supply in case the phantom returns.

[statjunk]

It isn't really the phantom that you fear it's the bill.

Tom

[Tucker]

Good day to all. The phantom struck again, as you all predicted. This time it won't quit. I can feel a hot spot on the tile (slab), so this 68 yr old will probably have to tunnel :mad:. As I understand it, the pipes are below the stressed concrete slab, so the culprit should be accessable without a jackhammer. My house is on Padre Island, on sand, so tunneling 5 to 10 feet is not a major thing except for tree roots and sore joints. What is the cause for a leak in the middle of a straight run of copper pipe? There is no significant cracking in the slab. Can it be just expansion and contraction fatigue from temperature variations over 22 years? Should I make the fix with a special flexible connection of some sort to relieve future stress? The option to install above-slab pipes would require a lot of visible pipe to a lot of places. Yes, the expense in water and gas is the driving reason to do the fix, plus no really hot water.

[Terry]

http://upload.wikimedia.org/wikipedia/commons/thumb/7/71/Piratey%2C_vector_version.svg/180px-Piratey%2C_vector_version.svg.png (http://en.wikipedia.org/wiki/Image:Piratey%2C_vector_version.svg)
Arrr!" So we were right!

Why would copper leak under concrete?
Could be done by a pick, corrosion, bad fitting
Concrete and copper are not a good mix.
Whatever you repair with, make sure it doesn't come in contact with the concrete.

[jadnashua]

I'd be very leary about tunneling under the house, especially with sand which could shift, bury you or mess with the slab.

[geniescience]

ditto.

Film a documentary whatever you do.

david

[GrumpyPlumber]

I'd be very leary about tunneling under the house, especially with sand which could shift, bury you or mess with the slab.

Add to that the fact there may already be a washout from the leak.

[markts30]

I would bite the bullet and look into having the house re-piped...
One hot water leak now usually means many to follow soon.;..
Best to abandon all hot (at least) piping under the slab and re-run new piping overhead - I would do both hot and cold at once...

[GrumpyPlumber]

I think "Master" Mark said that too, I agree.
I'd look into getting it all above ground, find a point to connect both and not worry about having to cut future slab.

[Tucker]

IBeen off line for a while, practicing my mining skills. The bad pipe was only (?) 5 feet in and was kinked since day 1. I have removed most of the overhead sand and talked my visiting son (37 yrs old) into doing the temporary fix. He is more able to squirm into small places. Now I get hot water everywhere except in the kitchen. I just have to widen it a bit for the plumber to get in for the permanent fix. It sure is hot and humid in there--a fan was a must. Miners are a tougher breed than I.

[toolaholic]

Plumber didn't bury the lines!

[Tucker]

Plumber may crawl in the hole tomorrow to sweat in some unkinked pipe. Hopefully, the leak is due to just the kink, and not an indication that there will be more leaks. Maybe I should not be in a hurry to fill in the tunnel :( . It looks like they didn't straighten the copper when they uncoiled it or someone stepped on it. Does anyone know if it is necessary to get the sand back in so that it goes up to the concrete? If so, how?

[toolaholic]

One side was down 3 1/2" I jacked it up! Long story. But after excavating and pouring new footing, I knew I still had some sluff off. I had My laborers try to compact as best they could. With My Lazer temp. gun I marked the rediant tubes [3/8" copper] core drilled 2" holes in slab. Had a grout pump with 2" nozzel pump in conc. with fly ash, added to mix. Fly ash makes the the concrete slick! Two struct. Eng., I use ,told Me I couldn't do this repair,I did.House is nuts on level now! Drainage problems corrected.

[Tucker]

The fix is in! The Plumber friend was able to crawl in and sweat a new section of copper pipe in where the kink was (see attachment). I held the fan to cool him off and blow out the fumes. No leaks so far, but I will wait a few weeks to fill in any sand.
The rate of things breaking seems to be going up! Just a day ago the home AC quit (guests due in shortly). Luckily the only problem was a recurring one--Roasted Ants in the relay (attachment 2). Blew them out and sprinkled ant killer around. Works now.