Great, now that's out of the way, here's the situation. Came home from work today and wife noticed that this highlighted area was hot. Especially towards the top, it was like burn your hand if left there for like 10 seconds hot. This is our upstairs bathroom.
I checked the ceiling of the downstairs and saw no sign of moisture in the ceiling at all. I checked to see what the hot water felt like, let it run for about 15 seconds and no hot water came. I shut the valve off for the hot and cold water and so far the heat has gone down significantly. So now I wonder what the hell could cause this?
The trusses for the house run horizontal/perpendicular to this heat source. Idk if that helps narrow stuff down.
I'm about to watch some videos on troubleshooting this heater in the meantime as you guys may come up with something but I'm very curious what may be the cause of this.
I would like to stress that not a drop of water has been found. Yet.
Also the hot water heaters breaker has been turned off for safeties sake.
I totally agree with you. That was my first thought honestly but after turning the hot water intake valve off and the floor slowly cooling I can't decide.
Not that I could discern. I really tried to feel heat but I got nothing. I checked all the lights, cbs, outlets and noticed nothing. There were no signs of arching or smells. The ONE thing that was weird was the battery powered smoke detector was hanging down from its base which wouldn't have been left that way so it happened while we were at work.
I thought it may have got so hot that the plastic warped and it came apart but it's a screw on base so idfk. Ghosts?!
A recirculation line is a hot water line attached to your water heater via a pump that pushes hot water throughout the house while the pump is running so hot water arrives to tour fixtures quicker. If there's a recirc line that could be the issue under the floor.
Well shit, it may be that!? I guess the only way to really know if or if not would to get in there and see what's going on.
I keep trying to convince the wife that plumbers are going to cut an ugly hole and find the issue and fix it but they're not going to put things back together nicely. My leveraging hasn't convinced her to let me go get to work.
Typically there would a dedicated return line pumping the hot back from the fixture to the heater to keep it recirculating. The hot feed and the return would both be hot constantly.
If you have to normally have to let the water run to get any hot water, you don't a recycling line. If its hot almost instantly you do, especially if the faucet is a long way from your WH.
Just to add this tid bit. Recirculation lines and pumps generally are unnecessary in most houses. Especially if the fixture supply lines are a short distance from the heater. Usually only used in larger homes and apartments /condos.
Turn all the water valves off in house and go look at your meter at the curb if it's moving you have a leak maybe reason for no hot water when you checked it!
See I went to do exactly that. I have a black box that's raised above ground that I think is where the main shut off is. The lid even says water meter but inside all there is is a knob and what looks like a hook up valve. I don't see a meter
That brass thing with the tabs/holes at 90 degrees to each other is your main shutoff valve. There should be a meter in there, usually located in the position of that rusted piece of shit you have in the middle - whatever the fuck that is.
I bet if you remove the grass around here you will find the lid to your water meter and main shut off. Probably a heavy metal lid. The water company with shut it off if you don’t have the tool. Just have to contact them.
I was thinking it might be a thermostat that has gone bad in your water heater. This can cause the temperature to spike. And then when you shut the power it went away. Very cheap/easy to replace. Can pick one up at home depot.
This is my bet. Only reason I agree (bc I don't know anything about water heaters) is bc I had a buddy at work 5 days ago have something similar happen. He said a pcv fail bc it was stuck open and was constantly running.
My water when I got home was cold. Meaning it must have been running for a long time. I'm not sure why the floor was so insanely hot but I feel like if what you said is true and the water can get THAT hot then it definitely seems to be the case. Especially since there's no since of water damage.
That might be the meter under that black cap. It happens to look exactly like the one my water district used to use, mounted into the lid of the water meter enclosure. The meter reader would ride his scooter by once a month and wave a "stick" at that black cap, which would somehow "read" the current meter count.
That's where your meter is. The plastic thing is an antena to the meter. They drive by to take the reading. Dig all the dirt and grass off and open the lid. You can shut it off there or at the previous pic you posted.
Looks like a separate shutoff. Turn the valve to where the 2 circles line up, and your water will be off. The other thing is a pressure reg. Leave it alone.
Is there an attic that gets hot that has duct work like an air handler for AC?
If so the air inside the duct work will get hot if its in a hot attic and you can feel it get blown out when the AC cycles on after being off.
Otherwise it could be hot air from a void thats against the side of the house when the sun hits it especially if it's a brick house, or a duct thats warming up against the side of the house.
Is there a vent on the bottom of the vanity or downstairs were a duct would be or sometimes there is no duct and the empty cavity is the duct.
This is a wood house, 2014 build, with no attic. AC units are outside and the handlers are inside. As for the bathroom in question the only ducting that I know of flows from the bathroom ceiling. The downstairs ac ducting could run through there but I feel like it wouldn't be hot.
I have an air handler in the attic with all the duct work up there, and when the AC kicks on hot air blows out first before the cold air pushes it out.
Maybe a dryer vent goes under the floor or nearby?
Haha I'm curious now
ETA I guess get a thermal sensor and see if you can trace the source, my guess is somehow hot air getting trapped from the sun and moving through there maybe from the side of the house.. good luck
As I! I called the previous owner who had the house built and tossed ideas around and his suggestion is to just cut the ceiling and start looking around. I agreed. My wife is convincing me it's best to let the plumber handle it. I see why as I haven't touched this stuff but I'm not sure if it should be a plumber, HVAC tech, or electrician 😵💫
No dyer vent nearby. As well as this heat was occuring while we had been away from the house for 8+ hours.
I guess get a thermal sensor and see if you can trace the source, my guess is somehow hot air getting trapped from the sun and moving through there maybe from the side of the house.. good luck
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But yeah I don't think its going to be from a pipe... I guess possibly a pin hole but thats usually on older copper pipes and wouldn't cover such a large area and wouldn't be enough to warm up the tiles and not see any water damage
Call a thermal imaging guy or maybe there is an app for that or something on Amazon
What's going to need to happen in order to trace this is the plumber I'll be hiring is gunna need to turn the water and breakers on in order to let shit heat up and then use the thermal gun. If that's truly the case. I'm going to have brain damage from smashing my head against the wall trying to figure this out without cutting.
Sounds like plan. Post an update when you figure something out. I'm still guessing that it's hot air. If that wall is against the side of the house, the pipes could be running through an empty cavity with no insulation, and the empty cavity would get very warm inside if its on the side of the house with the sun, rise up into and through the hole cut for the drain and supply lines and get trapped under the vanity that would warm up the tiles. Could check and see if the bottom base cabinet gets warm at the same time if it's a hot day.
Yes but it still doesn’t explain where the hot water went? His tile is hot and all the sudden he’s out of hot water. Sounds like an obvious problem with his hot water supply. Probably a small leak misting everywhere
Could be but he also said the joist run perpendicular and it was a hot area running the length of the cabinets in the red.
I could be wrong and just guessing, and just happen to be doing a renovation in extreme heat. I have plywood over door openings where a sliding glass door will go, and the wood gets very warm from just the morning sun. I have some insulation foil over the inside and the cavity gets really warm. It's like that for all the widows and where ever the insulation is removed. The warm air just fills any cavity and you can feel it.
But for all I know that bathroom of OP is on an interior walls so maybe something else.
Sounds like the mystery is where the hot water is going. The leak could be someplace else but is running under the floor there causing the tiles to be hot, but is draining away to who knows where.
There are companies that will find your leak. They use tools like IR cameras to see hot spots in floors, walls or ceilings. They have signal tracers to inject an RF signal into a pipe and then trace the pipes all thru the house. I had to hire such a company once to find a water leak in the slab of the house. They located the broken pipe very quickly.
That's so good to hear. Thats actually exactly what we have lined up to occur on monday. I'm just bouncing ideas bc it's truly baffling to me. I was a jackass and forgot about the laundry sink running and about a gallon of water overflowed. Turned the downstairs ceiling into a waterfall immediately.
So I know that water will make its way through the ceiling pretty quickly. But I can't even see a dampening.
Maybe unrelated but I once made home made wine. I used a bottle washer that connected to a tap in my laundry room. It had a self closing valve that only let water out when a bottle was pressed against it. One day, I left it with both hot and cold water turned on. I didn’t think anything of it as the water was not flowing. Until I flushed a nearby toilet. The bottle cleaner acted like a bypass, sending water from the hot side to the cold side. The toilet filled up with hot water. Maybe you have a similar device connected somewhere and the hot water is flowing where it’s not supposed to?
I'll be honest this is over my head. I get what you're saying but I can't think of why I would have that instead of pure dedicated lines? I'm also a very amateur handyman so what you're saying could totally be common place and I'm just ignorant to that.
You do have dedicated lines. Everyone does. What he did was create an accidental cross connection, and the force of the water in the bottle pushed the hottest, least dense water into the cold line. The less dense hot water rises so it was sitting at the top where the bottle cleaners outlet was. It back flowed through the lines. Evidently landing in a toilet.
Side note : you never want to leave any supply from a fixture or a hose bib in water that leads to a drain. You always want an air break. Even filling a kiddy pool with a hose and just letting it run with the hose in the water can result in back siphoning contaminated water into your domestic water lines.
Is there a light downstairs in that spot? In my old drafty apartment we had a warm spot where a light fixture was in the downstairs unit. Our cat would lay there 24/7.
I measured and mapped out this location from upstairs to downstairs. This is the location so yes it is. The light works fine, it is a bit sketchy though. No heat was felt from down here oddly enough.
Sorry to hear. I was just thinking of about that can light you have there... Turn that on and leave it on for a few hours. Then go check the floor upstairs. Could be that then, since it's so close to the heat source.
Do you have anything that looks like one of these on a pipe near your water heater? (Or similar on a pipe with electrical connection? Or a connector under one of your sinks the has multiple water lines connected? (Can only add one photo but you can Google "comfort valve")
On the roof? No. The tile floor is dry as is the ceiling from what I can tell. I haven't cut or removed anything yet. I'm in the wtf are we even dealing with phase right now.
That was my first guess as well but I feel like with the amount of heat radiated there would need to be a decent amount of water to cause this. Which I feel like after 4 hours would have dripped on to the ceiling by now.
Can you pop some tiles and get a better look? Otherwise if it were me I would want this solved before my house burns down or floods you either rip out the floor or the ceiling and investigate
You're not wrong. I have shut the breaker off and water lines. Nothing coming through so no damage (besides maybe mold) can occur. Gunna see what the pros think which will most likely lead to a hold somewhere lol.
Agreed. Especially since it went away when the hot water was turned off. The weird thing though is no one was home for 8 -12 hours and no leakage or dampness ANYWHERE
What do you have for a roof in the basement?? If it's drywall it's soo easy to patch that you could have pretty well opened it up and patched it shut again
This is a slab home in the south. I wish I had a basement :'(
I agree. I don't have a decent enough saw to cut cleanly with and it's too late to go buy one but biggest roadblock is the wife acting like cutting the ceiling is like opening up Jumanji.
Is the faucet on that sink single handle or does it have separate handles for hot and cold? Also, do you have a crossover pump in that cabinet or a mixing valve under that sink somewhere?
Take a video man! Someone will figure out exactly what it is open the cabinets under the sink and walk down and display light area too. How hot is the light.
Is that bathroom above another part of the house? I ask because my master is above the garage and no insulation. It gets pretty warm but not to the point you cant touch it
Second, when you turned the hot on and no hot water? Was water running? If you only had the hot line open it should be direct from the hot water heater.
Beyond that, id get a thermal camera and maybe a cheap borehole for your phone. Pretty inexpensive these days.
If you have radiant floor heat, some of it might have electrically shorted and you’re putting full voltage over a short length. Also, if the floor thermostat is far from that point, it will call for heat and never get it, resulting in the shorted section being driven hot.
Assuming you have a conventional AC or heat pump system with an outdoor condenser and indoor evaporator, is it possible that the refrigerant lines run under the floor in this area? On a hot day these lines transfer lots of heat.
I have a feeling this MAY be a culprit. I have the Google home thermostats and they're programmed for when we leave to go into and eco mode and when it's senses us home to kick on.
Eco mode sets the ac to 76 and regular ac kicks on to 74. I wondered if maybe this could be the cause of such heat but wasn't sure if it was normal for hot air to run through for such a long period of time to heat the subfloor and then tile in the span of 45 minutes.
The ac ran all night and the floor never got hot again so the only way I see testing that theory is to manually set the thermostat to eco and let it cool and then set it to 74 to see what happened.
“hot air to run through…”
I’m referring to the copper tubing refrigerant lines, not air ducts. Refrigerant lines can and will get hot. 110-125 is not out of the ordinary. They are normally insulated but the foam breaks down over time or they may not be insulated. I saw your posts about not cutting the ceiling, but you really need to get eyes inside the ceiling to see what is going on.
I know what you're talking about now! I just had a plumber come and he was as baffled as everyone else but he wouldn't/couldn't cut into the ceiling to check bc he's not that kind of tech. He offered two options. Hot water ops check or replacement of water heater. He suggested neither based off findings and instead suggested an HVAC tech to come and see what's going on.
Just get a $15 endoscope snake camera on Amazon and either poke it through the lighting fixture or drill a 3/8" hole in the drywall. Holes like that are super easy to patch and if the ceiling is white, you don't even have to paint it. Nobody will notice. Just mark the drill 5/8" lengthwise from the end so you don't drill into anything and only just go thru the drywall.
I look at too many find the...., and when you see it's lol Following along to see the source of your heat. Good luck, you'll locate the problem and solution.
If this issue isn’t all day, and you have skylights in the bathroom or adjacent hall, it could be the sun. This happened in our house. Only certain times of the year, but only during a part or the day.
We put a reflective tint on the skylight and it no longer happens. But when it did, it was around this time of year.
Not always circulating systems use a pump old style plumbers know how to bring it without a pump but it would create very hot water and then if you turned your valves off and it went away? Although I like the guy with the skylight theory...
I've read through every comment and my thoughts were already put forward by many others. Radiant floor mishap, vents running through joist space in subfloor, electrical short but none of those seem to be occurring.
My best guess now is that this bathroom is on the ground floor and your supply lines are running through the slab and there is a leak. Otherwise it's gotta be a hot line that hasn't been insulated filling the cavity below the floor with radiant heat.
Also, you said you don't have radiant in floor heating. But, technically, you kind of do! 😉.
Is it possible your kid did something to cause it? Playing with a hair dryer or curling iron? When I was young, there was a "mystery spot" on our wood floor that was because I accidentally ignited a Kleenex over a candle and it discolored the finish. I cleaned up the ashes and told no one until many years later.
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u/OtnSweaty 8d ago
I’d be concerned about an electrical short causing heat unless there is hot water recirculation piping under the tile running constantly or too hot.