Weird plumbing noise, warm hallway tiles?

[AZRedhawk44]

I have a Grundfos recirculation pump on my hot water heater.

I've just now unplugged it.

I hear a "whooshing" noise, like the sound pipes typically make when water runs through them.

I don't have any faucets turned on, though.

My house was built in 1977 and is slab construction.  To my knowledge, no pipes are run through the slab and they are all located in the attic.

Down my hallway, I have 3 hallway tiles that are extremely warm.

No moisture apparent from broken pipes or anything like that.  No lack of hot water; I can take a long shower with no problems.

Even with the recirc pump unplugged, the warm tiles are still warm and the whoosh noise is still going on.

Why?   

Even when plugged in, it was only set to go on a handful of times a day, for only 15 minutes.

I've even gone to the far end of the hot water line and turned off the hot water feed, which disables the hot/cold bridge that makes the recirc pump able to work.

So:
-Pump has no power
-Bridge is disabled.

I still have:
-Warm floor tiles
-whooshing sound of running water, but no faucets on and no wet walls anywhere and no water leaking out my foundation.

What the heck is up with my house?

[Torchman]

Perhaps your main waterline coming INTO the house?

[Jim147]

I think the first thing I would do is take a look at the water meter and make sure it's not spinning around.

jim

[AZRedhawk44]

Water meter at front of house is spinning.

I turned off the main and came back inside, drained the pipes.

Sound went away.

Evidently I have a leak somewhere in my hot system, but I can't see any leaks in the walls or around the foundation of the house.

And why the heck are my floor tiles hot?

[Northwoods]

Perhaps your main waterline coming INTO the house?

That would be making the tiles cold.  I know he's in AZ, but it is February.  The water there does get fairly cold in the winter time.

And why the heck are my floor tiles hot?

Are you sure there's not a radiant floor heating system?

[never_retreat]

Its hot because you have a leek on the hot side. Its just pissing into the gravel under the slab.
Time to get out the sledge and do some exploratory surgery.

[Nick1911]

Its hot because you have a leek on the hot side. Its just pissing into the gravel under the slab.
Time to get out the sledge and do some exploratory surgery.

This would be my guess as well.

What an odd situation.

[AZRedhawk44]

+1 for home warranties.

$49 and I don't have to worry about it.

Best $349 I'll probably ever have spent.

Main line is off, plumbing company coming in this afternoon to assess.

Probably leaking at a rate of 1 gallon per hour, looking at the front line's meter.  $#!+.  I don't see how that is warming the slab to where I can feel it though... that slow of a leak shouldn't have an effect on temp.

[Brad Johnson]

Probably leaking at a rate of 1 gallon per hour, looking at the front line's meter.  $#!+.  I don't see how that is warming the slab to where I can feel it though... that slow of a leak shouldn't have an effect on temp.

Soil is quite a good insulator.  If it's been leaking for a while it will, indeed, cause a hot spot in a slab.  Just how warm is dictated by location, conditions, etc.

Check and see if you have someone in your area that specializes in leak detection.  The ones around here are pretty good at diagnosing and pinpointing hard-to-find leaks.

Brad

[geronimotwo]

a stethescope can come in handy.

[AZRedhawk44]

Well, plumber is gonna do a pipe-otomy.

Run fresh pipe through the attic and cut the pipe under the slab.  Gonna cost me a pretty penny though.  Bummer.

[never_retreat]

Also don't rule out some sort of localized fission reaction, any nuclear waste dumps in the area? 

[Fly320s]

I don't see how that is warming the slab to where I can feel it though...

Leak in the drain/sewer pipe?

[Hawkmoon]

Water meter at front of house is spinning.

I turned off the main and came back inside, drained the pipes.

Sound went away.

Evidently I have a leak somewhere in my hot system, but I can't see any leaks in the walls or around the foundation of the house.

And why the heck are my floor tiles hot?

There are usually two hot water systems in a house. One is for "hot water" -- the stuff you use when washing dishes or taking a shower. The other is for "heat." The stuff you get from the faucets and shower is "potable" hot water and that system is separate from the heating system (if you have hot water heat rather than air) so the drinking water won't be contaminated by "stuff" from the boiler.

I have no idea what kind of system may be in your house, but it sounds like the house may have a radiant heated floor slab, which would mean a network of heating water pipes in the slab. It may be that one of those has spring a leak.

[Gewehr98]

There are usually two hot water systems in a house. One is for "hot water" -- the stuff you use when washing dishes or taking a shower. The other is for "heat." The stuff you get from the faucets and shower is "potable" hot water and that system is separate from the heating system (if you have hot water heat rather than air) so the drinking water won't be contaminated by "stuff" from the boiler.

 

Looking around my place for that elusive second hot water circuit...

[CNYCacher]

Probably leaking at a rate of 1 gallon per hour, looking at the front line's meter.  $#!+.  I don't see how that is warming the slab to where I can feel it though... that slow of a leak shouldn't have an effect on temp.

Sure it's not measuring cubic feet?  That's about 7 gallons.

[RocketMan]

Can we come watch when your house falls into the sinkhole the leak made?  

[p12]

A small leak will put out a lot of water.

The house in Lubbock we sold had recently had a foundation leak. Hot water side. They guessed the hole to be about half the size of a pencil lead. Over a 36 hour period it warmed about a 24 square foot area of the floor.

We did the trench-less repair. That's where they open the ends of the pipe at the manifolds and inject the epoxy stuff into the pipe. Works like a champ. No breaking any concrete and no running lines in the walls and attic.

$4k for the hot side. Insurance covered about 3/4 of it due to the 2 month old laminate that the leak was under.

[AZRedhawk44]

Plumber said it was no big deal.

He said that a "hot slab" leak is nothing to worry about once the problem is diagnosed and the hot water is turned off.

It will be a few days until I have it fixed, but he's just gonna bypass that set of pipes and run a new line through the attic.  Until then, I can turn on the hot water for showers and other uses, but I just have to turn it back off once done with it.

[Jim147]

"Nothing to worry about"

He's not the one with molemen digging up from near the earths core under his house.


jim

[MillCreek]

Or a cataclysmic volcano eruption.  But as HTG has taught us, these are not worth worrying about.

[Grandpa Shooter]

Red,

Been puzzling about this one.  Where is your hot water heater and is it in an interior space?  If it is interior, where has the TPC valve been plumbed to?  Is there any chance the heater is in an inside room and vented through the slab?  If so, and the TPC valve is defective it could be letting hot water escape through the in-slab vent line.  It would only heat a limited area before it cooled.

Just thinking?

[Jim147]

That is a good thought Grandpa Shooter. I see so few that are plumbed at all. Just waiting to leak all over the place or burn somebody that walks by and pulls on the little lever.

jim

[280plus]

Hah, I know a former sub sailor that thought that because he was on a sub at one time he could pipe his own boiler. Besides the fact that his piping was all wrong he left himself as couple extra branches on borth sides with ball valves and no plug/cap etc on them. I told him I thought he should oughta do something about that and I got the "Yea, sure, whatever you say buddy." look from him. 

Interesting because I just passed on a job similar to this. Two story condo though, I truly had no idea how to deal with it so I'm learning here. We normally have basements so it was the first time I had ever run into such a thing. I told them they needed someone who had more experience with that particular problem. Would my only choice have been to run up TWO floors to the attic? Somehow I knew chopping up concrete to find where the leak is was not the answer.

Plus it became obvious that this problem had existed for a while and they WERE getting a warm floor out in the middle of the living room, so I have to wonder how much it is undermined. 

They discovered it when they pulled up the glued carpet pad and the water started oozing out the crack it was covering. 

 

[AZRedhawk44]

Red,

Been puzzling about this one.  Where is your hot water heater and is it in an interior space?  If it is interior, where has the TPC valve been plumbed to?  Is there any chance the heater is in an inside room and vented through the slab?  If so, and the TPC valve is defective it could be letting hot water escape through the in-slab vent line.  It would only heat a limited area before it cooled.

Just thinking?

TPC valve?  What's that?

The heater is in my laundry/utility room on the far west side of my house.  If the TPC valve is the copper one in the center with the funny lever on it, it vents outside.

The heater is probably 40 feet away from the warm tiles.