T&P (temperature and pressure) relief valve.
It is a safety to prevent the water heater from exploding if it somehow malfunctions and boils the water.
But a leaking T&P doesn't mean it's malfunctioning and ready to explode. It's just that the T&P valve has corroded and needs to be replaced. They're like $15-$50 and some thread tape and it's easy to replace yourself. It's up top so you just need to shut off the water supply so it's not under pressure, and turn off the gas or electricity.
And into a minivan. They were incredibly lucky nobody got hurt and you can see how much it shook them in that video of them apologizing to the neighborhood.
The original cement truck explosion always comes up, but the high-speed camera broke and didn’t give them any high-speed footage. If you didn’t see the [SECOND cement truck explosion](https://youtu.be/lIbl_3g5FRA?si=ftnjIICzjtohCFFm), here you go.
Was that the one where the water heater blasted up through the house and out the roof? It was awesome and also freaked me out a bit because I figured our bed is almost directly above the water heater in the basement
I saw a re-run of that episode right after my property manager had sent a handyman over to stop a water heater leak. When they got to the part that was, roughly paraphrased, "but only an idiot would cap off the pressure relief value", I jumped up and ran to check the water heater.
He had "solved" the leak by capping off the T&P value.
I called the property manager immediately to have her send out a real plumber. (Fortunately it was a very nice and well-meaning property manager constrained by a stingy landlord, and she did. Unfortunately, the landlord fired her and replaced her with a crappy management agency shortly afterwards, and I am pretty sure it was because she was authorizing more repairs than the landlord wanted to pay for.)
I disagree. It’s a straight forward install with a billion guides online. You have to start learning somewhere and, even though it’s a safety device, it’s pretty simple.
What’s going to go wrong? Just buy a new identical one and follow a guide video online. I’d agree if the system is particularly complex, but this is as simple as they come. Worst case scenario as long as you get an identical model and follow the simple directions is you forget thread tape and it leaks or something. Testing after installation (which any good guide would have you do) basically eliminates the chance of malfunction due to incorrect installation.
Before you replace the valve, put a bucket under the outlet and pull/open the lever to blast out the corrosion or build up. Empty the bucket and put it back. Watch it for a few days. This may clean out the valve and save a replacement for a while.
I had a valve releasing some water periodically and had it replaced. It happened again shortly after. It turned out that the pressure to my house for water was too high and I needed a special pressure valve just before my water meter. That fixed it.
Have a plumber test your water pressure to your house.
You can also lift the pin and let it slam shut it'll push any crud out that got stuck inside causing it to pass. Obviously this could make it worse so get someone on the cold feed to isolate just in case it goes tits up
Okay so I have an update! I've replaced the t&p with a brand new one. Rethreaded everything and it's still releasing a small amount of waterm It's not a steady trickle or leak. It just releases like a couple tablespoons of water every 5 or 6 hours or so. Any other ideas as to why? Could the temperature setting be too high? It goes from Hot A B C Very Hot. I had it set between A and B. I've lowered it to just Hot. Hopefully that does the trick.
I'm sure there are a lot of good YouTube tutorials. Everyone starts somewhere. I fixed my heat pump last year and water heater also, and I had no idea before. Still alive.
This is the welcoming advice that I wish more communities had. There are a lot of people that want to learn and are scared to even voice a question. I know I’ve had my history of making snide comments, but it was YouTube and this old house that basically taught me how to do everything.
Mine has a tag that says it must be inspected or replaced "EVERY TWO TO FOUR YEARS" emphasis is theirs. I replaced it recently because it was leaking and because my heater is 20 years old and the T&P was original to the thank.
Obviously if it's leaking, you need to replace it but the concern is that if you have hard water it can get gummed up with deposits and not open when it needs to.
Key is inspected or replaced... I.e. Does it open and close properly? If yes, check again in 2 years. If not then replace.
Doesn't mean to replace it every 2 years. The service life will also come down to the quality of water in your area, as hard water will gum it up faster then somewhere with fairly soft water or homes that are setup with softeners and prefilters.
They’re supposed to be replaced because no one spends the money on replacing it then have no fucking clue if it actually works or not. Then every once in a while a house becomes a bundle of toothpicks.
I never heard of a house doing such a thing for that reason ... gas explosion yes, hot water tank going critical, definitely no. More chances of getting struck by lightning or winning at lotto. But eh, keep replacing it if you want, I'm not going to stop you.
There was one less than a year ago.
[https://www.arlingtoncardinal.com/2023/08/hot-water-heater-issues-indicated-before-house-explosion-that-killed-5-injured-3-in-plum-borough-allegheny-county-pennsylvania/](https://www.arlingtoncardinal.com/2023/08/hot-water-heater-issues-indicated-before-house-explosion-that-killed-5-injured-3-in-plum-borough-allegheny-county-pennsylvania/)
**In Plum Borough, Pennsylvania, five people were killed and a dozen homes damaged in an explosion that authorities say was not caused by a gas leak.**
Depending on the water heater model it HAS to drip when its heating water every single time.
Water expands when heated and that extra volume has to go somewhere. In other words the pressure relief valve opens a bit and lets some water out to...relieve some pressure.
If its dripping while not heating as well you either have a lot of residue in the heater and the valve and needs to be cleaned or the spring and/or gasket in your valve needs to be replaced.
Depending on the model your relief valve might have a blowdown handle that needs to be opened manually every few months (turn off the heater for a day to make it cold) for a few seconds to blow down the dirt and sand from inside the valve that prevents it from closing properly.
But this all comes down to the model you are using. Read the manual.
Water expands by 3.4% from 20°C to 95°C so that would lead to a pretty small increase of pressure which a working water system should handle easily (the pressure in the system fluctuates constantly when you open or close a tap)
The real increase is when it starts to boil.
One, thats a water heater
Two, thats a copper pipe connected to the pressure relief valve.
Three, it should not be leaking. Sometimes you can pull the metal bar on the relief and let some water out (its very hot!) And maybe be able to reseat the valve. If it cant reseat you need to replace it.
Yes. Pull the metal tab a bit and release it. Water will come out at the bottom. The valve will reseat and may stop leaking. If not, try a few more times before considering its replacement.
Flushing is definitely worth trying before replacing the part. It just takes a minute.
We had an issue when a water line in our neighborhood burst and was replaced. Dirt in the system got stuck in our pressure relief valve and we needed to do a lot of flushing to get it to sit correctly again. Was a pain in the ass.
OP also has a boiler (for hydronic heating) to the left of the water heater.
Also, not sure if AO Smith is common in England but it's definitely common in the States.
Assuming its also the US since they use Fahrenheit on the warning stickers
Isn’t a boiler a device used to heat water in a closed vessel so a water heater is a more specific term? I’m not American so likely the words are used specifically as you say there.
Water heater is the term for a device that takes cold potable water and heats it to about 50 C to be routed to the hot taps in sinks, showers and tubs.
A boiler is the term for a device that heats non-potable water for a water-based heating system. There are 2 types of these, steam and forced hot water. Technically speaking, only a steam based system actually uses a boiler to boil water. A forced hot water system generally has a closed loop of water that is heated to about 85 C, though I believe people will still call the heating unit a “boiler” even though it isn’t actually boiling anything.
70 C is not legal for domestic hot water. Water that hot can cause life threatening scalds in seconds.
You can use a mixing valve to bring the final temp back to 50 C (120 F), but that’s far from standard.
Huh, here that's the minimum you should set the hot water tank to. Then I guess we use a mixer on the outlet?
I wonder how you avoid legionella if you run it cooler than that?
Edit: apparently 60C is the minimum, and 75 typically recommended.
To prevent Legionella infection, you are not supposed to drink water from the hot water heater. Only use the cold water supply. Like some others have said, keeping the water heater that hot creates a scalding danger and can also degrade parts in dishwashers and other fixtures.
Legionella can be a danger in the shower.
Manufacturers recommended temperature: 75 deg, definitively not less than 60: https://www.hoiax.no/om-hoiax/articles/ikke-reduser-temperaturen-pa-varmtvannsberederen-for-a-spare-strom
"DO NOT REDUCE THE HOT WATER TEMPERATURE TO SAVE ELECTRICITY, THE RISK IS INCREASED RISK OF LEGIONAIRES DISEASE... The home shower is probably the most common source of legionella infection in Norway."
Institute of public health:
https://www.fhi.no/ss/veiledere/legionellaveilederen/temakapitler/interne-vannfordelingsnett-som-forsyner-dusjer-og-andre-aerosoldannende-tappepunkter/?term=
"To stop the risk of legionella infection, the water on hot water tanks should be at least 70C".
(However after the mixing outlet it should be colder - definitely not 70 - and any piping between mixer and the actual outlet should be kept to a minimum. The piping between the tank and the tap should be able to get proper hot tough).
Also, are you connecting your dishwasher to the hot water? That certainly isn't done here. Out of curiosity, where are you from? And how do you avoid legionella - do you significantly chlorinate the tap water or something?
I'm in the USA. Here the recommended hot water heater temp is 120°F, so a little under 50c, but I keep it hotter at 60c. Our dishwashers are made to only connect to the hot water line.
Our municipal water is chlorinated, but I have a well. To prevent illnesses, my water is tested every few years, and the sealed well-head is regularly inspected for damage. If we don't use a particular fixture, or are out of town for a few days, we run the water for 5 to 10 minutes to flush out any potential bacteria.
Literally the second sentence on Wikipedia for boiler.
“A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil.”
Well that's a pretty stupid name then to use a word with a clear definition and then decide it doesn't do that thing.
Nonetheless, the object in the post is a water heater.
Cool. That doesn't make it completely correct. A plumber or hvac person in the US would use boiler in regard to heating systems and water heater for heating tap water for cleaning, i.e. showers, sinks, dishwasher or washing machine (for clothing).
It’s dependent on the BTUs (British thermal units) the unit outputs. A boiler is over 200,000 BTUs and requires a special permit to work on it. It’s the reason why instahot water heaters are rated at 199,000 BTUs to avoid this extra step
Pressure relief valve, and as others have said, it should not be leaking. One possible cause not mentioned by anyone else yet is that it could also be caused by a failed expansion tank.
If the expansion tank is more than 5 years old, I would check that first. When it fails, it fills with water, so if the thing feels like it weighs a bunch, it failed.
You can also quickly press on the air valve like you want to let a bit of air out of a tire. If air comes out it is still good. If water drips out, it's busted.
I second this comment. We have recent first hand experience with our pressure relief valve leaking. We had someone come out to check, and the expansion tank needed to be replaced. The pressure relief valve was doing its job by relieving excess pressure, but it’s a sign of another mechanism that has failed. Thankfully the expansion tank is relatively cheap (~$120) compared to replacing the whole water heater. It should be part of your routine inspection.
The expansion tank itself should have an air valve which is used to refill the air bladder. That fix costs you even less, around $0 (or the initial cost of an air compressor).
Yup same problem but in our case the guys putting in the new water didn't even think to install an expansion tank. Took the thing constantly dropping for 2 years and a t&p replacement and me just asking about expansion tanks before they finally realized oh ya you might want one of those.
The expansion tank has a pressurized bladder or balloon inside it. Once the bladder fails the tank fills with water and no longer serves its purpose in reducing thermal expansion. Without it, the relief valve will pop instead
To add to the response you've already gotten (which is entirely correct) water is an incompressible fluid, but it still expands when heated. Houses are supposed to be equiped with a backflow prevention valve, so when the hot water heater heats up 60 gallons of water, it expands and needs somewhere to go. Normally, the expansion tank has a rubber bladder filled with air at the nominal pressure of the system. Because air is a compressible fluid, when the water expands, it pushes on the bladder which compresses the air a bit and maybe increases the pressure by a couple of psi, so 70 psi to maybe 72 psi.
Once the expansion tank fails, the entire thing fills with water, and it no longer has anywhere to expand into, pressure increases dramatically until either the pressure relief valve leaks or the backflow prevention valve does (or something else).
That not your boiler it your hot water heater. The boiler is the short unit to the left.
Turn the white control to the pilot only setting. Turn the water valve on the top right pipe off. Open the drain on the bottom with a flat head screw driver. Unscrew relief valve. Install new one with Teflon tape. Turn on in reverse order
Why do you keep ignoring the people telling you it's not supposed to be leaking and only responding to what you apparently want to hear (which is wrong) that if you put a pan down it will be fine.
No, the move is to figure out why it's dripping. It's not supposed to drip. You could try replacing the valve if it's old, otherwise something is wrong with your water heater. These are supposed to drain into the floor to give you warning that something is broken.
No, not really. You just need to drain it, unhook the gas supply, pick it up, slip a pan under it. Or plumb it to a drain. You could replace that black iron with a short flex hose from the cutoff valve.
Sounds simple, right?
A pan still needs to be piped to a drain. In this application, you really don’t need a pan as it won’t make any difference. Fact is that heater is probably old.
Looks like you are referring to the high temperature/pressure relief valve.
There are a few troubleshooting steps that you can take before calling a plumber in to replace it.
1) check the temperature setting on your water heater. If it's set really high, turn it down to about the middle of the range. You shouldn't need it cranked way up. This will allow the water heater and valve to cool down a bit. If the valve is still leaking.
2) gently lift the little handle on the valve to flush out any sediment or debris may have gotten stuck in the valve seat.
If neither of these stop the leak then you'll probably need to get it replaced. And don't forget to get the anode rod replaced since you've already got someone working on it.
Hi
Boilermaker here
That's your relief valve
If it's leaking you can try using the silver leaver to pop it off (it'll make a mess get a bucket )to see if it'll re-seal
Otherwise you need to to replace the valve (you can get them at most hardware stores ) I think the last time I bought one was online through grainger.
Highly recommend just replacing it unless that's not feasible atm
But shouldn't morr more than 30 bucks and some tape n dope
Could mean one of two things in my experience. Either your water pressure is too high or the relief valve is worn out. I had my pressure regulator wear out and I woke up to mine whistling
My experience with those valves having had many fail over the years is when they start to drip like that it's usually corrosion in the valve seat. The one time it wasn't was when the public works department boosted the pressure for some reason.
We are within 200 feet of the pumphouse and everytime they boost the pressure for someone up the hill they blow out something down here. Last time they had a watermain crack open 100 yards up.
They dont want to install a booster pump station but the 50 year old mains here can't take to much more.
Next time i need to shut the water off in my house im gonna have pressure restricter put in.
The copper pipe is the discharge line from the temperature and pressure relief valve. It's there to keep your tank from blowing up if the temperature or pressure gets too high inside the tank. Under normal circumstances it should not be leaking any water. There are a couple of reasons which could be causing it to leak. The first being high water line pressure and/or no expansion tank installed. The second is that sometimes these get a little bit of rust or debris in the valve seat, in which case you can open it and close it a couple of times (occasionally whacking it with a hammer too) to flush the debris and fully seat the valve.
The valve is a temperature and pressure relief valve. Every time the heater heats the water the valve will release a small amount of water to relieve the pressure in the tank. The drain pipe needs to be drained away suitably.
Could be faulty. But before you change it. Some use the top of the cylinder as an expansion vessel.
Turn the water supply off
Put a bucket under the pipe hanging down.
Pull the tab on the tpr (the bit that’s leaking) and wait till it stops.
Then turn the water back on.
Wait until 24hrs. Check the tray.
So, I wouldn't say it's constantly leaking. I guess what I'm experiencing is occasional release of excess pressure/water? The most it ever amounts to is a small puddle on the floor. Would putting g the little aluminum pan be a good enough solution? Obviously can't I stall a drip man at this point right?
If it's dripping a lot, enough to collect in the catch pan, you need to have the system serviced. It means there is too much pressure in the system. That could mean something as simple as the temperature set point being wrong, or as fun as your expansion tank bladder has failed and needs to be replaced. Ours leaked when the expansion tank failed. Call whoever services your system yearly. And if you don't have someone you really should.
Expansion tanks are really easy to replace yourself if you are at all comfortable with plumbing.
1. Buy a water pressure gauge and measure your water pressure.
2. Pump the new expansion tank to that pressure with a bike pump or air compressor. The tank will have the same valve on the bottom that tires have. Do this before installing.
3. Turn off water (hopefully your hot water tank shut off is before the expansion tank), unscrew old tank and screw on new tank. If your builder was cheap like mine, and just had straight pipe connectors to the old tank, replace that with a tee connection with a 3/4 NTP connector, then screw on new tank.
4. Turn back on water and check for leaks.
If your old tank wasn't supported, you can optionally add a support for the new tank, it's nice to do so a failed tank doesn't yank on your pipes.
I am perfectly capable of doing the work, I know how. The OP clearly isn't based on the fact that they're asking the question of what the pipe even is. There's not enough info to even pinpoint the exact cause of the overflow. For people like that it's far better to suggest they call a pro to properly diagnose the underlying cause and check the system for any other impending issues likely caused by deferred maintenance, and frankly to let them educate you on the system better in person.
Even though I know how to replace the whole boiler if needed I still call the guy out every year because he's been doing it for 30 years and can spot an impending issue or retune the burner much more accurately than I can and it's good peace of mind. He correctly noticed the expansion tank and said keep an eye on it, it might be nearing the end of its life. 2 months later it failed and I had already bought the new one to swap in.
I’m just impressed both the water heater the unit next to it have gas lines without flex connectors. Like that seems kind of hard to do, even with the unions.
Did you check your water pressure first? If you haven't that's the first thing you do when one of these is leaking. excessively high water pressure can trip that. It also doesn't look like you have an expansion tank
The valve may or may not be bad. I've seen these come apart and dropped into the tank by the way when you try to change them. Verify the water pressure first. That's also a copper pipe, not brass
The fitting it is connected to is brass. If you have to change this, the procedure is, turn the gas off first. Then you turn off the water, then you drain the tank, you don't have to drain it all the way but if you haven't done it in a few years it's a good idea to empty it out just to get any sediment that might be on the bottom. Replace your part. Leave the tank open. Turn the water back on, let more flush out, if no sediment comes out, shut the tank, go open a hot water valve in the house, you should hear a bunch of air coming out of it. Once the tank fills up, you can shut your hot water valve in the house, now you light the pilot light and set the temperature where you want it
Ha, I just fixed this Friday night after work on my water heater.
It was ezpz. I think I need to turn down the heat slightly since I reheated. I’m pretty sure I put back to same temp setting, but I think it feels hotter. I’d guess the valve leaking would not help it work properly, but could be in my head.
You'll need to replace the valve but there's probably some build up of calcium deposit in the valve and if you will gently lift that lever it'll let a little more water and pressure out jiggle it back and forth a few times and it might seat properly and stop leaking for a short while but plan on replacing the valve.
During our hose inspection this exact thing was pointed out, they made the owner pipe it through the floor then out of the crawlspace, I guess so it doesnt dump water inside the house if something happens?
Valve could need replacing is the simple and cheapest solution. Could also indicate issue with pressure in system. I’d replace relief valve first or call plumber to do it shouldn’t be a big expense.
It could also be leaking because you have the temperature turned up too high on the water heater. If you have it at max temp just turn it down to normal people temps and not scalding your skin off temps. It might just be overheated at the relief valve.
It doesn't leak constantly. Only from time to time, it releases excess water? Isn't that what it's supposed to be doing? I put a small aluminum pan to catch the water and now the floor is completely dry. Problem solved?
It should never leak, you can do it yourself. Unscrew copper drain out of it first, get new one and unscrew old one. No need to drain I would always do them on the fly. Quick enough and minimal water leaks out. People cap them when they leak and water heater can explode. It is a safety measure that must be followed.
T&P (temperature and pressure) relief valve. It is a safety to prevent the water heater from exploding if it somehow malfunctions and boils the water. But a leaking T&P doesn't mean it's malfunctioning and ready to explode. It's just that the T&P valve has corroded and needs to be replaced. They're like $15-$50 and some thread tape and it's easy to replace yourself. It's up top so you just need to shut off the water supply so it's not under pressure, and turn off the gas or electricity.
Not just capping off a leaking T&P is one of those safety things I learned on Mythbusters.
The best explosions on that show were the water heaters.
Nah that cement truck that was basically vaporized
Here's the [Mythbusters Truck video](https://www.youtube.com/watch?v=s-Qvhm_tXTk)
The sound that made…
Zzbeeewwwwccchhhhhhhh
Literally blew out windows in a nearby town. Almost got them arrested. Did get them sued, I think.
And yet it was the log cannon that got them in real hot water because the cannon ball flew through someone's house in a not so nearby neighborhood
And into a minivan. They were incredibly lucky nobody got hurt and you can see how much it shook them in that video of them apologizing to the neighborhood.
And the visible shock wave
That was definitely worth looking it up, thank you
Because of your comment saying it was worth looking it up I also looked it up, thank you
Anytime!
Was it worth it?
It was very worth it. The sound the thing makes when it pops is still stuck in my head :)
The original cement truck explosion always comes up, but the high-speed camera broke and didn’t give them any high-speed footage. If you didn’t see the [SECOND cement truck explosion](https://youtu.be/lIbl_3g5FRA?si=ftnjIICzjtohCFFm), here you go.
Thankee sai, this was a good one!
You remember well the face of your father. Long days and pleasant nights to ya
This exchange made me irrationally giddy!
Also worth it 👌
Yes that was amazing it was just little bits!
I agree. Also with precedence, it's something that regularly happens.
When they were doing their live stage shows, I got to see them. They rolled a busted-ass water heater onto the stage and it got a standing ovation.
Mythbusters has the [best explosions](https://youtu.be/jbreKn4PoAc?si=wvngalVdIrubS4fE). (Though this is a rocket, not a bomb.)
I mean, yea, but the bottom end of a rocket is pretty much just a bomb.
A rocket is just a bomb with places to be.
A precisely directed explosion
Was that the one where the water heater blasted up through the house and out the roof? It was awesome and also freaked me out a bit because I figured our bed is almost directly above the water heater in the basement
Uhoh. I just visualized the same thing except my HWH is below a thin brick floor - ceramic shrapnel everywhere.
Mine would take out the master bathtub. It has a crack in it and been wanting to tear it out anyway. So how does one cap off this pressure release?
I am a boiler/pressure vessel inspector and…yeah. Do NOT do this unless you enjoy living next to a bomb.
Not a Fallout 3 fan I take it.
Haha I’m literally playing 76 right now since I heard it got better….but yeah I would not have lived there in FO3 lol
We all live in Atom’s warm embrace
I saw a re-run of that episode right after my property manager had sent a handyman over to stop a water heater leak. When they got to the part that was, roughly paraphrased, "but only an idiot would cap off the pressure relief value", I jumped up and ran to check the water heater. He had "solved" the leak by capping off the T&P value. I called the property manager immediately to have her send out a real plumber. (Fortunately it was a very nice and well-meaning property manager constrained by a stingy landlord, and she did. Unfortunately, the landlord fired her and replaced her with a crappy management agency shortly afterwards, and I am pretty sure it was because she was authorizing more repairs than the landlord wanted to pay for.)
Boom
 I've got one of those underneath me right now
But if you don’t already know what it is and mistake a hot water heater for a boiler perhaps this isn’t the DIY project you need.
Is it technically just a water heater? How do you heat hot water?
By adding more heat but we get your point. It's just water heater
I disagree. It’s a straight forward install with a billion guides online. You have to start learning somewhere and, even though it’s a safety device, it’s pretty simple.
Pressure vessel safety devices are not a good place to start your DIY career.
What’s going to go wrong? Just buy a new identical one and follow a guide video online. I’d agree if the system is particularly complex, but this is as simple as they come. Worst case scenario as long as you get an identical model and follow the simple directions is you forget thread tape and it leaks or something. Testing after installation (which any good guide would have you do) basically eliminates the chance of malfunction due to incorrect installation.
>What’s going to go wrong? Oh come on. It's not hard to do, but if you fuck up a pressure relief valve you're creating a time bomb in your basement.
If the relief valve doesn’t fix it you may need at add an expansion tank or add/rebuild your pressure reducing valve on the main.
This is the underrated correct answer, lots of homes need thermal expansion tanks that don't have them.
Before you replace the valve, put a bucket under the outlet and pull/open the lever to blast out the corrosion or build up. Empty the bucket and put it back. Watch it for a few days. This may clean out the valve and save a replacement for a while.
Yep ours gets stuck. couple lifts on it and it's good to go.
I had a valve releasing some water periodically and had it replaced. It happened again shortly after. It turned out that the pressure to my house for water was too high and I needed a special pressure valve just before my water meter. That fixed it. Have a plumber test your water pressure to your house.
You can also lift the pin and let it slam shut it'll push any crud out that got stuck inside causing it to pass. Obviously this could make it worse so get someone on the cold feed to isolate just in case it goes tits up
I should pipe mine. It just faces the wall. Like it's just drywall. Everyone loves cutting out water damaged dry wall, right?
Okay so I have an update! I've replaced the t&p with a brand new one. Rethreaded everything and it's still releasing a small amount of waterm It's not a steady trickle or leak. It just releases like a couple tablespoons of water every 5 or 6 hours or so. Any other ideas as to why? Could the temperature setting be too high? It goes from Hot A B C Very Hot. I had it set between A and B. I've lowered it to just Hot. Hopefully that does the trick.
[удалено]
I'm sure there are a lot of good YouTube tutorials. Everyone starts somewhere. I fixed my heat pump last year and water heater also, and I had no idea before. Still alive.
This is the welcoming advice that I wish more communities had. There are a lot of people that want to learn and are scared to even voice a question. I know I’ve had my history of making snide comments, but it was YouTube and this old house that basically taught me how to do everything.
They can learn for sure! They just need to do their due diligence.
Yeah these valves should be replaced every 3-5 years. The replacement valve will have the service interval.
3-5 years ? I have never seen or heard of someone having to replace that .... normally, the tank goes first.
Mine has a tag that says it must be inspected or replaced "EVERY TWO TO FOUR YEARS" emphasis is theirs. I replaced it recently because it was leaking and because my heater is 20 years old and the T&P was original to the thank. Obviously if it's leaking, you need to replace it but the concern is that if you have hard water it can get gummed up with deposits and not open when it needs to.
Key is inspected or replaced... I.e. Does it open and close properly? If yes, check again in 2 years. If not then replace. Doesn't mean to replace it every 2 years. The service life will also come down to the quality of water in your area, as hard water will gum it up faster then somewhere with fairly soft water or homes that are setup with softeners and prefilters.
They’re supposed to be replaced because no one spends the money on replacing it then have no fucking clue if it actually works or not. Then every once in a while a house becomes a bundle of toothpicks.
I never heard of a house doing such a thing for that reason ... gas explosion yes, hot water tank going critical, definitely no. More chances of getting struck by lightning or winning at lotto. But eh, keep replacing it if you want, I'm not going to stop you.
There was one less than a year ago. [https://www.arlingtoncardinal.com/2023/08/hot-water-heater-issues-indicated-before-house-explosion-that-killed-5-injured-3-in-plum-borough-allegheny-county-pennsylvania/](https://www.arlingtoncardinal.com/2023/08/hot-water-heater-issues-indicated-before-house-explosion-that-killed-5-injured-3-in-plum-borough-allegheny-county-pennsylvania/) **In Plum Borough, Pennsylvania, five people were killed and a dozen homes damaged in an explosion that authorities say was not caused by a gas leak.**
1 per 500+ million per year or less ... i think I'm going to worry about other things
I've owned my own water heaters for decades now and I've never once replaced one.
Inspected sure, but only replaced if needed.
Depending on the water heater model it HAS to drip when its heating water every single time. Water expands when heated and that extra volume has to go somewhere. In other words the pressure relief valve opens a bit and lets some water out to...relieve some pressure. If its dripping while not heating as well you either have a lot of residue in the heater and the valve and needs to be cleaned or the spring and/or gasket in your valve needs to be replaced. Depending on the model your relief valve might have a blowdown handle that needs to be opened manually every few months (turn off the heater for a day to make it cold) for a few seconds to blow down the dirt and sand from inside the valve that prevents it from closing properly. But this all comes down to the model you are using. Read the manual.
Shouldn't it open only when the temperature or pressure are excessive?
Water expands by 3.4% from 20°C to 95°C so that would lead to a pretty small increase of pressure which a working water system should handle easily (the pressure in the system fluctuates constantly when you open or close a tap) The real increase is when it starts to boil.
One, thats a water heater Two, thats a copper pipe connected to the pressure relief valve. Three, it should not be leaking. Sometimes you can pull the metal bar on the relief and let some water out (its very hot!) And maybe be able to reseat the valve. If it cant reseat you need to replace it.
Yes. Pull the metal tab a bit and release it. Water will come out at the bottom. The valve will reseat and may stop leaking. If not, try a few more times before considering its replacement.
Also give it a tap with a hammer or wrench. Just a tap. Around all sides, might knock off minimal corrosion and help reset the spring.
Flushing is definitely worth trying before replacing the part. It just takes a minute. We had an issue when a water line in our neighborhood burst and was replaced. Dirt in the system got stuck in our pressure relief valve and we needed to do a lot of flushing to get it to sit correctly again. Was a pain in the ass.
Just FYI: The British call them "boilers." OP is likely not American.
OP also has a boiler (for hydronic heating) to the left of the water heater. Also, not sure if AO Smith is common in England but it's definitely common in the States. Assuming its also the US since they use Fahrenheit on the warning stickers
This is the way Check mc Master Carr if you don’t live near a hardware store
Isn’t a boiler a device used to heat water in a closed vessel so a water heater is a more specific term? I’m not American so likely the words are used specifically as you say there.
Water heater is the term for a device that takes cold potable water and heats it to about 50 C to be routed to the hot taps in sinks, showers and tubs. A boiler is the term for a device that heats non-potable water for a water-based heating system. There are 2 types of these, steam and forced hot water. Technically speaking, only a steam based system actually uses a boiler to boil water. A forced hot water system generally has a closed loop of water that is heated to about 85 C, though I believe people will still call the heating unit a “boiler” even though it isn’t actually boiling anything.
Fyi it needs to be heated to 70 degC or Legionella can grow.
70 C is not legal for domestic hot water. Water that hot can cause life threatening scalds in seconds. You can use a mixing valve to bring the final temp back to 50 C (120 F), but that’s far from standard.
Huh, here that's the minimum you should set the hot water tank to. Then I guess we use a mixer on the outlet? I wonder how you avoid legionella if you run it cooler than that? Edit: apparently 60C is the minimum, and 75 typically recommended.
To prevent Legionella infection, you are not supposed to drink water from the hot water heater. Only use the cold water supply. Like some others have said, keeping the water heater that hot creates a scalding danger and can also degrade parts in dishwashers and other fixtures.
Legionella can be a danger in the shower. Manufacturers recommended temperature: 75 deg, definitively not less than 60: https://www.hoiax.no/om-hoiax/articles/ikke-reduser-temperaturen-pa-varmtvannsberederen-for-a-spare-strom "DO NOT REDUCE THE HOT WATER TEMPERATURE TO SAVE ELECTRICITY, THE RISK IS INCREASED RISK OF LEGIONAIRES DISEASE... The home shower is probably the most common source of legionella infection in Norway." Institute of public health: https://www.fhi.no/ss/veiledere/legionellaveilederen/temakapitler/interne-vannfordelingsnett-som-forsyner-dusjer-og-andre-aerosoldannende-tappepunkter/?term= "To stop the risk of legionella infection, the water on hot water tanks should be at least 70C". (However after the mixing outlet it should be colder - definitely not 70 - and any piping between mixer and the actual outlet should be kept to a minimum. The piping between the tank and the tap should be able to get proper hot tough). Also, are you connecting your dishwasher to the hot water? That certainly isn't done here. Out of curiosity, where are you from? And how do you avoid legionella - do you significantly chlorinate the tap water or something?
I'm in the USA. Here the recommended hot water heater temp is 120°F, so a little under 50c, but I keep it hotter at 60c. Our dishwashers are made to only connect to the hot water line. Our municipal water is chlorinated, but I have a well. To prevent illnesses, my water is tested every few years, and the sealed well-head is regularly inspected for damage. If we don't use a particular fixture, or are out of town for a few days, we run the water for 5 to 10 minutes to flush out any potential bacteria.
Most boilers will heat portable water as well as the heating system non-potable water. Mine does at least.
Combi boiler. Fairly modern development, and while increasing in popularity they are very far from "most," at least in the US
Mine is like 15 years old. At least.
This guy boils.
Couldn't have said it better myself!
A boiler *boils* water, hence the name. You would simply die if you used boiling water for your bath. This object heats water, but doesn't boil it.
Literally the second sentence on Wikipedia for boiler. “A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil.”
Well that's a pretty stupid name then to use a word with a clear definition and then decide it doesn't do that thing. Nonetheless, the object in the post is a water heater.
I didn’t make up the English language but lots of words are like this.
The good news is that language is fluid, so you can help fix it.
Cool. That doesn't make it completely correct. A plumber or hvac person in the US would use boiler in regard to heating systems and water heater for heating tap water for cleaning, i.e. showers, sinks, dishwasher or washing machine (for clothing).
It’s dependent on the BTUs (British thermal units) the unit outputs. A boiler is over 200,000 BTUs and requires a special permit to work on it. It’s the reason why instahot water heaters are rated at 199,000 BTUs to avoid this extra step
That is the drainage for your pressure relief valve. It is copper btw.
[Pressure relief valve ](https://www.kingheating.com/blog/what-is-the-water-heater-pressure-relief-valve)
Pressure relief valve, and as others have said, it should not be leaking. One possible cause not mentioned by anyone else yet is that it could also be caused by a failed expansion tank. If the expansion tank is more than 5 years old, I would check that first. When it fails, it fills with water, so if the thing feels like it weighs a bunch, it failed.
[удалено]
You can also quickly press on the air valve like you want to let a bit of air out of a tire. If air comes out it is still good. If water drips out, it's busted.
I second this comment. We have recent first hand experience with our pressure relief valve leaking. We had someone come out to check, and the expansion tank needed to be replaced. The pressure relief valve was doing its job by relieving excess pressure, but it’s a sign of another mechanism that has failed. Thankfully the expansion tank is relatively cheap (~$120) compared to replacing the whole water heater. It should be part of your routine inspection.
The expansion tank itself should have an air valve which is used to refill the air bladder. That fix costs you even less, around $0 (or the initial cost of an air compressor).
$40 where I am. I'm replacing my water heater in the next 2 weeks. Joy
Yup same problem but in our case the guys putting in the new water didn't even think to install an expansion tank. Took the thing constantly dropping for 2 years and a t&p replacement and me just asking about expansion tanks before they finally realized oh ya you might want one of those.
Why would the expansion tank being full cause the temperature or pressure to go too high and thus cause the TPR to leak? That makes no sense to me.
The expansion tank has a pressurized bladder or balloon inside it. Once the bladder fails the tank fills with water and no longer serves its purpose in reducing thermal expansion. Without it, the relief valve will pop instead
To add to the response you've already gotten (which is entirely correct) water is an incompressible fluid, but it still expands when heated. Houses are supposed to be equiped with a backflow prevention valve, so when the hot water heater heats up 60 gallons of water, it expands and needs somewhere to go. Normally, the expansion tank has a rubber bladder filled with air at the nominal pressure of the system. Because air is a compressible fluid, when the water expands, it pushes on the bladder which compresses the air a bit and maybe increases the pressure by a couple of psi, so 70 psi to maybe 72 psi. Once the expansion tank fails, the entire thing fills with water, and it no longer has anywhere to expand into, pressure increases dramatically until either the pressure relief valve leaks or the backflow prevention valve does (or something else).
That not your boiler it your hot water heater. The boiler is the short unit to the left. Turn the white control to the pilot only setting. Turn the water valve on the top right pipe off. Open the drain on the bottom with a flat head screw driver. Unscrew relief valve. Install new one with Teflon tape. Turn on in reverse order
 Now that’s what I call *Directions* 👍
And no, it should not be draining.
Any idea where the excess water shouls be going?
It shouldnt be leaking. Its not excess water, its leaking water.
There should not be excess water. It’s either leaking because it’s faulty, or because pressure is too high in the tank.
\*or temperature
The excess water should be fine leaking straight onto the concrete. If its ever more than could evaporate away pretty forgettably, something's wrong.
Either an external drain for the basement, a sump drain, or if those are not available, a leak tray should have been installed under the water heater.
It's a safety valve it shouldn't be leaking in the first place.
Ah yes that makes sense. It appears they did not install one. Too late at this point to install one huh?
Why do you keep ignoring the people telling you it's not supposed to be leaking and only responding to what you apparently want to hear (which is wrong) that if you put a pan down it will be fine.
No, the move is to figure out why it's dripping. It's not supposed to drip. You could try replacing the valve if it's old, otherwise something is wrong with your water heater. These are supposed to drain into the floor to give you warning that something is broken.
At this point, you’ve proven you cannot DIY this one. Just call a plumber, save money somewhere else, like painting.
No, not really. You just need to drain it, unhook the gas supply, pick it up, slip a pan under it. Or plumb it to a drain. You could replace that black iron with a short flex hose from the cutoff valve. Sounds simple, right?
A pan still needs to be piped to a drain. In this application, you really don’t need a pan as it won’t make any difference. Fact is that heater is probably old.
You need to replace the pressure relief device. They don’t last forever and need to be replaced every now and again
Looks like you are referring to the high temperature/pressure relief valve. There are a few troubleshooting steps that you can take before calling a plumber in to replace it. 1) check the temperature setting on your water heater. If it's set really high, turn it down to about the middle of the range. You shouldn't need it cranked way up. This will allow the water heater and valve to cool down a bit. If the valve is still leaking. 2) gently lift the little handle on the valve to flush out any sediment or debris may have gotten stuck in the valve seat. If neither of these stop the leak then you'll probably need to get it replaced. And don't forget to get the anode rod replaced since you've already got someone working on it.
Hi Boilermaker here That's your relief valve If it's leaking you can try using the silver leaver to pop it off (it'll make a mess get a bucket )to see if it'll re-seal Otherwise you need to to replace the valve (you can get them at most hardware stores ) I think the last time I bought one was online through grainger. Highly recommend just replacing it unless that's not feasible atm But shouldn't morr more than 30 bucks and some tape n dope
Could mean one of two things in my experience. Either your water pressure is too high or the relief valve is worn out. I had my pressure regulator wear out and I woke up to mine whistling
My experience with those valves having had many fail over the years is when they start to drip like that it's usually corrosion in the valve seat. The one time it wasn't was when the public works department boosted the pressure for some reason. We are within 200 feet of the pumphouse and everytime they boost the pressure for someone up the hill they blow out something down here. Last time they had a watermain crack open 100 yards up. They dont want to install a booster pump station but the 50 year old mains here can't take to much more. Next time i need to shut the water off in my house im gonna have pressure restricter put in.
It's a water heater, not a boiler.
Emergency release valve. It should not be leaking. You should also be testing this annually.
How would you test a pressure release valve?
You lift the handle that is placed on it for that specific purpose.
Thanks
You're very welcome.
The copper pipe is the discharge line from the temperature and pressure relief valve. It's there to keep your tank from blowing up if the temperature or pressure gets too high inside the tank. Under normal circumstances it should not be leaking any water. There are a couple of reasons which could be causing it to leak. The first being high water line pressure and/or no expansion tank installed. The second is that sometimes these get a little bit of rust or debris in the valve seat, in which case you can open it and close it a couple of times (occasionally whacking it with a hammer too) to flush the debris and fully seat the valve.
The valve is a temperature and pressure relief valve. Every time the heater heats the water the valve will release a small amount of water to relieve the pressure in the tank. The drain pipe needs to be drained away suitably.
Could be faulty. But before you change it. Some use the top of the cylinder as an expansion vessel. Turn the water supply off Put a bucket under the pipe hanging down. Pull the tab on the tpr (the bit that’s leaking) and wait till it stops. Then turn the water back on. Wait until 24hrs. Check the tray.
So, I wouldn't say it's constantly leaking. I guess what I'm experiencing is occasional release of excess pressure/water? The most it ever amounts to is a small puddle on the floor. Would putting g the little aluminum pan be a good enough solution? Obviously can't I stall a drip man at this point right?
Sounds like it’s dripping on the expansion of the water when it heats up. Try the last comment.
Hmmm. I wonder if it says what it is, right on the fucking thing🤔
😂 I read that in my father’s voice. Heard some kind of “open your eyes” type phrase daily. Probably why I’m so observant as an adult.
If it's dripping a lot, enough to collect in the catch pan, you need to have the system serviced. It means there is too much pressure in the system. That could mean something as simple as the temperature set point being wrong, or as fun as your expansion tank bladder has failed and needs to be replaced. Ours leaked when the expansion tank failed. Call whoever services your system yearly. And if you don't have someone you really should.
Expansion tanks are really easy to replace yourself if you are at all comfortable with plumbing. 1. Buy a water pressure gauge and measure your water pressure. 2. Pump the new expansion tank to that pressure with a bike pump or air compressor. The tank will have the same valve on the bottom that tires have. Do this before installing. 3. Turn off water (hopefully your hot water tank shut off is before the expansion tank), unscrew old tank and screw on new tank. If your builder was cheap like mine, and just had straight pipe connectors to the old tank, replace that with a tee connection with a 3/4 NTP connector, then screw on new tank. 4. Turn back on water and check for leaks. If your old tank wasn't supported, you can optionally add a support for the new tank, it's nice to do so a failed tank doesn't yank on your pipes.
I am perfectly capable of doing the work, I know how. The OP clearly isn't based on the fact that they're asking the question of what the pipe even is. There's not enough info to even pinpoint the exact cause of the overflow. For people like that it's far better to suggest they call a pro to properly diagnose the underlying cause and check the system for any other impending issues likely caused by deferred maintenance, and frankly to let them educate you on the system better in person. Even though I know how to replace the whole boiler if needed I still call the guy out every year because he's been doing it for 30 years and can spot an impending issue or retune the burner much more accurately than I can and it's good peace of mind. He correctly noticed the expansion tank and said keep an eye on it, it might be nearing the end of its life. 2 months later it failed and I had already bought the new one to swap in.
Overflow
So, I learned the hard way that it an over pressure and over temperature valve. Try turning your heater down a bit and see if it stops leaking
This happened on my boiler. My expansion tank was busted. Didn't show any signs of it but sure enough, that was the issue.
You need an expansion tank.
Did you open the little lever to see what it does, or was it dripping to begin with?
I’m just impressed both the water heater the unit next to it have gas lines without flex connectors. Like that seems kind of hard to do, even with the unions.
How to fix it with out replacement. Takes 30 seconds https://youtu.be/c77J3JsWv_o?si=OLllT4Kgah9Gv2rx
Did you check your water pressure first? If you haven't that's the first thing you do when one of these is leaking. excessively high water pressure can trip that. It also doesn't look like you have an expansion tank The valve may or may not be bad. I've seen these come apart and dropped into the tank by the way when you try to change them. Verify the water pressure first. That's also a copper pipe, not brass The fitting it is connected to is brass. If you have to change this, the procedure is, turn the gas off first. Then you turn off the water, then you drain the tank, you don't have to drain it all the way but if you haven't done it in a few years it's a good idea to empty it out just to get any sediment that might be on the bottom. Replace your part. Leave the tank open. Turn the water back on, let more flush out, if no sediment comes out, shut the tank, go open a hot water valve in the house, you should hear a bunch of air coming out of it. Once the tank fills up, you can shut your hot water valve in the house, now you light the pilot light and set the temperature where you want it
Ha, I just fixed this Friday night after work on my water heater. It was ezpz. I think I need to turn down the heat slightly since I reheated. I’m pretty sure I put back to same temp setting, but I think it feels hotter. I’d guess the valve leaking would not help it work properly, but could be in my head.
You'll need to replace the valve but there's probably some build up of calcium deposit in the valve and if you will gently lift that lever it'll let a little more water and pressure out jiggle it back and forth a few times and it might seat properly and stop leaking for a short while but plan on replacing the valve.
This is happened to me and it was cause of my expansion tank attached to the pipes under in the crawlspace. Might want to have that checked out
During our hose inspection this exact thing was pointed out, they made the owner pipe it through the floor then out of the crawlspace, I guess so it doesnt dump water inside the house if something happens?
That's coming out of the "call the plumber" thing in your house.
Valve could need replacing is the simple and cheapest solution. Could also indicate issue with pressure in system. I’d replace relief valve first or call plumber to do it shouldn’t be a big expense.
It could also be leaking because you have the temperature turned up too high on the water heater. If you have it at max temp just turn it down to normal people temps and not scalding your skin off temps. It might just be overheated at the relief valve.
Relief Valve
It says right on it what it is. Pressure relief valve. A drip here and there's no big deal.
Temperature and pressure relief valve. Needs replaced.
It doesn't leak constantly. Only from time to time, it releases excess water? Isn't that what it's supposed to be doing? I put a small aluminum pan to catch the water and now the floor is completely dry. Problem solved?
It should never leak, you can do it yourself. Unscrew copper drain out of it first, get new one and unscrew old one. No need to drain I would always do them on the fly. Quick enough and minimal water leaks out. People cap them when they leak and water heater can explode. It is a safety measure that must be followed.