Mystery hot water running

Tucker · Aug 26, 2007

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 · Aug 26, 2007

Tucker said:
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

Sponsor · 2022-01-29T12:20:58-0800

hj · Aug 27, 2007

leak

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 · Aug 27, 2007

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 · Aug 27, 2007

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 · Aug 27, 2007

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 · Aug 27, 2007

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 · Aug 28, 2007

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

Tom

Tucker · Aug 28, 2007

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

. 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 · Aug 28, 2007

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 · Aug 28, 2007

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

Geniescience · Aug 29, 2007

ditto.

Film a documentary whatever you do.

david

GrumpyPlumber · Aug 29, 2007

jadnashua said:
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 · Aug 29, 2007

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 · Aug 29, 2007

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 · Aug 31, 2007

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 · Aug 31, 2007

Don't blame the concrete Guys !

Plumber didn't bury the lines!

Tucker · Aug 31, 2007

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 · Sep 1, 2007

Tucker I also have a slab on grade home i repaired

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 · Sep 1, 2007

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.

Mystery hot water running

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