Do I need a thermal expansion tank? - Let's do an experiment!
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- čas přidán 1. 06. 2024
- Why do you need a thermal expansion tank? It's a common question among home owners and newer plumbers.
Well, the simple answer is because it saves your water heater from becoming a rocket. BOOM!
The long answer is because as water increases in temperature, it also increases in volume. So when we have a sealed system, That added volume of water will turn into tremendous pressure. That is unless we provide a place for that added volume of water to go.
First, we display just how much added water volume is created when we heat a 50 gallon tank of water. You'll be surprised at how fast it happens too!
Next, we perform the same test again but this time the pipes are sealed up so the added volume of water has nowhere to go. This means it turns into water pressure. It only takes a few minutes for the pressure to exceed 150 psi.
From there, we display a clear thermal expansion tank so you can see exactly what happens inside a thermal expansion tank. As the volume of water increases, the size of the rubber bladder decreases. This allows the water pressure to remain stable.
Finally, we showcase what happens to the water pressure when we install a thermal expansion tank. It's pretty neat to watch the pressure gauge while the thermal expansion tank get to work.
If you enjoyed this video, then make sure to give it a thumbs up and subscribe to the channel. We have many more informational videos like these in the works
For more great info, check out our other videos on this channel or visit our webpage at www.CallSmedley.com
@WattsWater @StateWaterHeaters @AOSmithWaterProducts @bradfordwhitewaterheaters5020 @rheemwaterheatertraining @fergusonenterprises @HomeDepot @lowes @menards
When learning about this expansion tank, there shouldn't be any other video than this one. You showed thermal expansion visually and with a pressure gauge. You showed us the bladder inside and how it works with an increase in pressure. You can't show any more about this topic. Nice job man
Thanks!
You can show the calculations used to get the proper sizes off the expansion tank's and also explain the different precharge pressure for different systems
@@noelburke6224 watts has a calculator just for that as well!
www.watts.com/resources/planning/etp
For real. This video is amazing! Thanks for sharing your knowledge!
Agreed
The reason you now need a thermal expansion tank is because public water supplies used to be "open." Basically just a pipe from the street to your house. When water in the water heater expanded, it could easily flow back into the public water supply. However, there were instances of stuff getting into the water supply so today most water meters have a "check valve" that prevents this from happening. So you need a thermal expansion tank nowadays. If you don't have one, among other things, the water heater tank will balloon out when the water pressure is high and then back in when it's not. This in and out tank expansion cracks the glass lining of the tank causing it to corrode and leak prematurely. So thermal expansion tanks make water heaters last longer. Also the greatly increased water pressure from thermal expansion often damages piping and valves on washing machines, dishwashers, ice makers, etc. and can cause pipe connections to leak. The temperature and pressure relief valve will open if the pressure gets too high, but if that happens frequently, the T&P safety valve can get clogged with sediment and may not work when you really need it to.
To check if you need a thermal expansion tank (or to test if the one you have is working), put a water pressure gauge anywhere on the cold water side of your plumbing system, then use a lot of hot water (so the tank will fill with cold) and watch the pressure gauge as the cold water is heated. If the pressure does not rise during a heating cycle, either you don't need a thermal expansion tank or the one you have is working. However, utilities come around and replace meters all the time so you may not need one today and could need one tomorrow. My neighbor (who, ironically, works for the water company) got her meter replaced (while at work). She had no expansion tank. A few days later, a plastic fitting under a bathroom sink couldn't take the higher pressure and her house was flooded (took six months to repair).
Finally, it's a good idea to get some leak detectors (they look a lot like smoke detectors) and put under sinks, near the HVAC system--anywhere water might leak. Has saved my house several times...
Great info!
I wondered about that. The real reason incoming line isn't open to the city if you have a pressure reducing device on the inbound line and it doesn't go backwards. Some places the city might be up near 90 pounds.
But if you have a well with a holding tank and your pump only pressurizes the line when there's a demand for water, you won't need an expansion tank.
@@mrcryptozoic817 I have a well with pressure tank. I feel that way as well, the well pressure is so low already, any that the tank creates can spread over the system just fine.
I would hope to God your hot water tank has a pressure relief valve....problem solved... literally the only country in the world which requires such a stupid system
@@kjemad The temperature and pressure relief valve (T&P) is mandatory. Designed to open at a specific high temperature or pressure, the T&P valve is a safety device. It is not designed to open every operating cycle. Depending on the hardness of the water, if used regularly to relieve pressure, the T&P valve can become clogged with sediment or debris which reduces its capacity or in some cases can cause it to fail completely. Also, T&P valves are rarely drained outside so there's that. An expansion tank on the other hand is designed to deal with the more frequent (lower) pressure spikes due to water expanding when heated. These occur every operating cycle. These devices do not do the same thing and one is not a substitute for the other.
Plumbing contractor for 40 years, always knew and respected thermal expansion and your video illustrated it perfectly! Thanks so much! Also, came from your other video where you compared box store water heater to pro grade. I was one of those who thought they were the same.... Not anymore! Great educational videos that are extremely well done!!! You Rock!!
Wow, thanks!
Been in the plumbing industry for 20+ years. The way this video is put together is PERFECT, definitely knows plumbing very well. Just make sure to run video at 1.25 speed so that it feels normal. 😁
Thanks!
😂
Agreed, even if you’re a newbie this was a little long and drawn out, but an excellent video nonetheless
I've watched a ton of videos of people complaining that teachers speak too fast. you can't please everybody...
I bought this water heater czcams.com/users/postUgkx8G49mV71sAzUl9shXyLW-r3XgHH9EVh1 for use in my bus conversion. I installed it under my kitchen sink and it is fed by a high efficiency on-demand LP water heater. It is both a backup hot water source as well as a water saving device since we have hot water on demand rather than having to wait for the gas on demand water heater to finish its ignition cycle. I decided on this water heater due to the fact that it only draws 1300watts when it's ON instead of the 1500 watts that most Water heaters this size draw. In an RV a couple hundred watts can be a big deal. With very low standby losses, I don't have to worry about excessive power consumption. When propane is not available for our gas water heater, in conjunction with our low flow shower head there is enough hot water available to shower, albeit we won't be taking "hotel showers." Also very happy with the recovery rate of this water heater. Granted, it is quite small, but it does exactly what we need it to do.
Thanks,!
I am a retired home inspector and never received this type of training. When I came across these tanks I only knew to check the pressure on both the water heater and the tank based on training myself through compairson between different homes. This is an excellent video and a valuable training aid to all...
Thanks!
I'm over here wondering why our public schools don't do what you just did. You sir are a legend. Keep it up!!
I appreciate that!
The school system is not keeping up with modern times.
Still teaching Romeo and Juliette as composary courses.
Go figure.
@@loktom4068 Actually now they are teaching critical race theory, gender confusion theory and Marxism.
@robbyneleson3 Exactly! Our school system needs to stop making our children feel guilty for not going to college. Forget bringing back trade programs to high school, we should be introducing kids to this type of material in elementary and middle school AND high school. I spent 12 years in the automotive industry, and now work in the hvac & home remodel industry. Both of my school age kids can identify a capacitor, a contactor, and more automotive parts than I care to count. If the schools won't do it, it's up to us to teach our kids everything we know. @Smedley Plumbing - Very awesome and well put together video! keep up the good work.
@@hoppershelpfulautomotive thanks!
This is one of the best documentary on expansion tank.
Thanks!
This should be a required part of the training every new plumber must receive. You did an outstanding job presenting this information in a way that every home owner, building inspector and tradesman will understand and remember. I’m really impressed!
Thank you! We are pretty proud of this video as well.
well when youre an actual REAL plumber that went to school anytime in the past 4-10 years its pretty standard to know id even argue earlier than 10 years but thats municipal dependent.
@@Astrnauted no need for hateful comments. Water all trying to share knowledge and learn here.
@@SmedleyPlumbing lol bud that’s not hateful. Just emphasis on real. Get a grip
Thank you very much for this valuable and educational video. Questions: What size expansion tank is needed for the 40 gal, 50 gal, and a 75 gal water heater tank sizes. The sizes I noted that are available on the market are like 2 gal and 4 gal. I've had a 75 gal tank heater for over 20 years and never have had an expansion tank, nor to my knowledge, had the pressure relief valve to open on its own to relieve the pressure. Would you kindly comment on the best path forward that i should pursue. Another question: Where on the water heater tank would you add a temp gauge if these gauges are available on the market. My old water heater doesn't come with either a pressure or Temp gauge, unfortunately. Thank you
HVAC guy here. This video was awesome. Thank you!
Glad you liked it!
Thank you so much for posting this video. About two years ago, our small town replaced the old water meters. Immediately after this, we noticed water on the floor of our basement at the bottom of our tank water heater, clearly from the PRV. We were having to empty a large plastic Folger's coffee container every 2-3 days. We were also experiencing a short blast of high pressure water whenever we would turn on a faucet. Uneducated about this particular area of plumbing, I was still smart enough to know that none of this was right....at all. It took several days of internet investigation and calls to Town Hall to find out that the new meters changed our water supply to a closed system. Long story short.....I have a Watts thermal expansion tank (honestly...because that's the label on your tanks...lol) arriving this weekend. And I've already installed a secondary inline PRV. I just didn't trust the PRV on the tank for some reason. Again, we cannot thank you enough! You can't imagine the stress you have relieved in this household. This video should be the Gold Standard for all educational videos posted! You truly did a fantastic job. We have subscribed and clicked the bell......you've got us for life!! ❤😊❤
Boom! That's why we do this! Glad we could help!
What a GREAT demonstration! You should mention that it is code in many locations to put those in. This is because municipalities are putting in backflow preventers at residential meters and the water has nowhere to go. With no backflow prevention the water simply goes back out into the main. We know that, but people that don't know what expansion tanks are don't.
Correct. Problem is nobody knows if there are checks in the system. If they aren't blindly required by the local code, then it's best to perform a pressure test and monitor pressure through the heating cycle. Code doesn't technically require them but local municipalities sometimes do. Code just requires that thermal expansion must be controlled when it's present.
@@SmedleyPlumbing it's probably the safest option to expect at least a Dual Check valve. Cannot be tested, and I'm seeing lots of them in default meter installations in many locations. Some meters have them built in to the meter assembly itself, or put in with the meter.
Not having one with a check valve will damage the system and the check valve itself. Over back-pressures the check disks. Thanks 😊👍
Why would it go back into the main? I'd just expect my house to have really good water pressure
@@johnpeace971
In a 3/4" line, how much water VOLUME from the street to the water tank would TRULY backflow into the system when pressurized? I mean seriously this is a farce. The water that actually did go back into the system would never have left it in the first place.
@@brianreinhardt4050 He demonstrated in the video that for his given temperature rise, about a quart of water is displaced. Assuming negligible expansion of the system you can assume that the volume of water that would backflow is roughly a bit less than that quart, that backflow would only start to flow once the system pressure was greater than the incoming main pressure.
As a retired plumber of 48 years, I used to be puzzled at how many people did not know basic physics. Now I realize my Earth Science teacher in 9th grade was a jewel, Thanks Mr. Rice, Central High, Cheyenne Wyo. 1969
Comes in handy sometimes!
Awareness principle, it blows my mind that people don’t naturally understand the things I regularly look at. Then, I remind myself that I don’t know jack shit about computers compared to every single person I know.
@@bojanglesobrien6883 True, though one is actually the world around us, we feel touch and see from birth. The other is a man made object
I am on a municipal water system with no backflow preventer installed. Now I know why an expansion tank was not installed on my water system.👍🏻
Quite possibly. It's always good to test with a pressure gauge during a heat cycle of the water heater just to make sure.
I was under the impression that water heaters were an “open” system, so did not need expansion tanks. By contrast, hot water heating systems were “closed” and thus needed the expansion tanks., Thank you, and other commenters, for educating me. I plan to add an expansion tank as a result.
I have asked this question - to tank or not to tank - of a number of professionals and none seemed confident in their responses. Their answers were limited to “what they’ve seen.”
Your point about the anti-corrosion glass liners cracking, exposing the tank metal to corrosion, makes a lot of sense. It seems to me that it should be possible to detect such a breakdown, which would give you some warning that the water heater was living on borrowed time - unless the liners are frequently defective from the start.
Indeed, I wonder why expansion components re not integral to the water heaters.
I begin to understand why my first water heater split a seam after less than seven years. The replacement heater just passed the four year mark.
Based upon your videos, I should replace the anode and add an expansion tank as soon as I can - if I want this heater to last.
Glad we could help!
All true if the house has a PRV or some form of backflow prevention (i.e., check-valve, not all do!) as that won't allow water to expand back into the system, causing the excess pressure. If the house doesn't have a a PRV or check valve an expansion tank is NOT needed. My home has neither a PRV nor a tank. That being said, good explanation of why many homes DO need a tank!
Thanks!
One other thing you should add to your discussion is the potential effect of added pressure to any weak pipe connection in the system, for instance a buried elbow hidden inside a living space wall. For anyone still using Polybutylene pipes, a thermal expansion tank could mean significant added life to their water supply system. I did an in depth study of thermal expansion tanks a few years ago and I now have them both at my home and my vacation home as well. Thanks for the video, the visualization of the water expansion and the baloon in the bottle were highly instructive, great lateral thinking on your part.
Thanks. We could go on for a while on the damages thermal expansion might cause. Or next video will highlight the worst case scenario....🤯
No one could have done a more thorough and effective job of explaining all this as you did. I learned so much. Great job!
Glad it was helpful!
Yes my friend , you did wonderful job for mechsnical contractor
Thank you
Owned many homes for decades, never needed an expansion tank. Never had a problem
They are only needed when check valves or pressure regulation valves are installed on the main incoming water line.
Another big thing to know is whether your incoming water to your house has a one way check valve at the water meter. If there is one you are defiently going to need an expansion tank. In my area there is no check valves for the incoming water supply. So an expansion tank is not required. Great demonstration.
Yep. Best way to test for the presence on a check valve is with a pressure gauge.
Isn't a check valve required to prevent potential contamination of the municipal water supply?
@@dubmob151 yes. You're exactly right.
also if you are pumping from a well or cistern... in that case there is already a large expansion tank, so putting another little one on the heater is redundant... right?
@@Sean_y4k2l5 correct. If you're on a well or cistern, your bladder tank also serves as an expansion tank.
I am a retired marine engineer and was aware of how an expansion tank works because we had similar but much larger systems on boar made by a company called Newpress. I watched your video just to see how good an explanation you were going to give an I must admit you did an excellent job of explaining how the system works and why you need expansion tanks in a sealed system. The only thing I would add, if I may, is the reason why your expansion tank doesn’t collapse like the water bottle did. Thanks that was a very well explained tutorial with excellent demonstrations. Thank you.
Yeah the water heaters are never subjected to negative pressure. Plus they are more durable than a plastic bottle.
OKAY, IMO,,,,,,,,,,THEE BEST PLUMBING VIDEO I EVER SAW DEALING WITH ANY SUBJECT........I DEBATED WATCHING CAUSE I CAN'T WATCH LONG TEACHING VIDEOS...............TOO MUCH NONSENSE AND USELESS JIBBER JABBER..........THIS ONE HAD NONE OF THESE DRAWBACKS..........YOU ARE AN EXCELLENT TEACHER.......YOU EXPLAIN TO BE UNDERSTOOD...........I LEARNED A LOT...........SUBSCRIBED ,,,,,,,,,,,AND LOOK FORWARD TO MORE OF YOUR VIDEOS.........CAN'T BELIEVE 31 MINUTES WENT THAT FAST AND I DIDN'T FAST FORWARD ONE SECOND OF THE VIDEO.........A GREAT BEYOND GREAT VIDEO........WISH MORE WERE LIKE YOURS...........YOU DON'T TALK TOO FAST OR SLOW,,,,,,,,,,,JUST RIGHT,,,,,,,,,,,,,ONCE AGAIN JUST MY OPINION.........BUT PROBABLY A LOT OF OTHERS TOO...
Thanks!
Greetings from the Gambia🇬🇲. Im a plumber in my 5th year apprenticeship. You can follow nice meeting my fellow plumbers😊❤
Welcome!
@@SmedleyPlumbing thanks. Nice works you got there I really appreciate your efforts
I think you about covered every angle on this ! I installed a pressure reducing valve on our system in addition to the expansion tank. The PRV definitely closes to system but I believe very essential to reduce pressure to fixtures to 50 psi max. They will last longer. Our input pressure is over 80 psi at the meter . I also think that the expansion tank may prolong the tank life by retinue the amount of expansion/contraction inside it. For those who think 80 plus psi is nice, be aware that most well pumps only deliver within a 30-50 psi range.
Thanks!
To add a few things that might help those who aren’t quite aware of symptoms and causes …
First, don’t do testing like that in your own home. Learn by watching the video, not by being a copycat.
Residential plumbing codes in most jurisdictions in the USA have an upper limit of 80 PSI as the maximum pressure to feed plumbing fixtures. In many places the incoming municipal water will have a pressure well above that (my house had 105 PSI when I last measured it), so a pressure reducing valve (PRV) is installed just past the water meter. As far as I know, all PRVs for residential water prevent back flow to the water meter; and many water meters also prevent back flow into the water service lines. So expanded water isn’t able to flow back into the water service lines in most cases.
So where does it go if there is no expansion tank and the T&P isn’t dripping?
Old ball float toilet valves were good for letting the expanded water flow through them and then down the overflow tube ;)
Old faucets with washers and seats would often have a wear point that would let the expanded water drip through.
So it’s quite possible that a dripping faucet or running toilet is an indicator that you need an expansion tank.
Yes sir. Some prv's allow for back flow but the interior pressure must exceed the incoming pressure before it can happen. In those situations, you're right back to the elevated pressure you were trying to prevent by adding the PRV.
Great video. There is no "more water". It is expanded water. As you show, if the pressure gets high enough to be a danger, the pressure relief valve opens and reduces the pressure. At best, expansion tanks save you this wasted water. And there is also a second safety valve that pops on water heater should the pressure relief value fail. One would think water heater makers would include an expansion tank inside the water heater, but they are cheap. I bet they could sell a lot if they did that though since it save installation time. Also, the pressure does not keep building and building until the water heater explodes, provided the thermostat is working. It shuts off the heating and the pressure stops increasing. To make the water heater explode, you have to disable the pressure relief valve, block the emergency pressure plug, and disable the thermostat. Doing that is crazy since it make the water heater a bomb.
Have you seen the video where we tried that?
Also, expansion tanks not only keep the water heater from exploding. They also maintain a system pressure of less than 80 psi which is the max pressure allowed by code.
This is an awesome explainer video! Thank you! Now I am educated and can educate 😊
Thanks!
This is all very simple, but what is usually missed is that you do NOT need one of these unless you have a backflow preventer. most old houses do NOT have such a thing, so when the water begins to expand it simply pushes the extra volume back into the water main. Water supply systems use centrifugal pumps, and thus water can be pushed backwards through them, and on a huge city system, there is always a tap open somewhere.
Having a pressure regulator valve would also require the need for a thermal expansion tank.
@@SmedleyPlumbing Nope, not unless it has an integral backflow preventer which I can tell you mine doesn't. A regulator alone doesn't stop backflow. I added a regulator 20 years ago because my water pressure is 125 psi, no issues at all, in just the last couple months I added an exp tank because the stupid local inspector doesn't know his ars from a hole in the ground, and the pressure still rises about 15 psi after you stop running water as the tank heats, but at least it doesn't have to reach the 125 psi main pressure before it has relief.
@@integr8er66 if incoming pressure is elevated (say 120 psi) and then the reducing valve brings that pressure down to 70 psi, the interior pressure would need to build up to over 120 psi before a bypass PRV will allow reverse flow. So you're right back to the elevated pressure you were trying to protect against with the prv until someone opens a faucet.
So… no danger of 155psi pressure buildup when water is supplied from the city with no back flow obstruction
In my case, the water comes in at 60psi
@@-.__.__.-Rad all depends if the city has a check valve in their meter.
Thanks for taking your time to show us this. Excellent work!
You're welcome! And thank you!
I wish my plumber had watched this. Instead I put up with 13 yrs of a dripping T/P valve, then finally installed one myself. Thanks for educating us all!
Sorry to hear that. Glad you fixed it though!
Outstanding explanation, thank you. Being from the old school when we were informed for the need an expansion tank it was perplexing. What are and for, what reason do we now needed one when for decades there were not such a thing. They told us "it is now code" without any further explanation. Again, thank you for your video.
In your next video mount the camera. It is unnerving watching a video with the camera bouncing around, where do we focus? Oh, please remove the background music, it is very distracting and annoying. It is beyond me why CZcams content creators think it cool-cute-necessary, having music playing over their voice. We came to hear you, not fight the music. Many folks have hearing difficulties, thus when we attempt to hear the spoken works and there is music as well, we cannot turn up the volume without turning up the volume of the music. In a word frustrating. To understand what you are saying what we must do is turn on the CC. Hope this makes sense.
Thanks for the feedback
I'm in St. Louis. Customers, especially older ones, are all so skeptical of "that blue ball thing that you put on my water heater". I've developed a pretty good understanding of thermal expansion and I feel like I'm able to explain it pretty well, but this video is a game changer. Thanks for putting in the time.
That's exactly why we made the video! Put this info to use!
Can you learn everything about everything then teach it all to us just like this? Great job, appreciate the time and effort you put in this video for us.
I appreciate that!
Outstanding video that teaches the plumbing. Good job i learned a lot from you.
Glad you enjoyed it!
Hopefully done a good job he says
This is a definitive video for the explanation of the use and need for a hot water expansion tank.
Thank you
Thanks!
I truly appreciate the amount of time and effort put into this video, setting up the visuals and also editing it all together.. with incredible quality both audio and video. Very hard to come by videos this great today.
Glad you enjoyed it!
I used to live in the Midwest, now I’m in East Phoenix. Almost all residential water distribution is above ground out here. I can remember when I’d only been out here a few months, I was home in the middle of the day and tried to take a shower when it was ~115° outside.
On full cold the water was just shy of scalding, 120°+. It was at the extreme upper limit of tolerable for me - and then only for exceedingly short periods.
So yeah, no doing laundry or showering in the middle of the day unless you’ve got some MacGyver projects already in flight.
Another piece of trivia showing Arizona is not a suitable environment for humans: there’s a phenomenon of people in motorcycle/traffic accidents, or pedestrians struck by vehicles, wherein the victim ends up on the blacktop and suffering more serious injuries from having laid or fallen on the ground than from the collision which threw them to the ground.
Stay where there’s trees & grass & seasons & most of the people on the interstate aren’t from LA. Where using your turn signal isn’t considered a sign of weakness. I’ve wandered off topic and into a nostalgic rant, my apologies.
Enjoy your content.
Cheers!
Thanks! Enjoy AZ for us!
I've been a plumber for 40+ years. I think you nailed it.
Thanks!
If you are responsible for the plumbing setup in your video... 👏👏👏! Beautifully done!
Thanks!
Seeing the demonstrations helps me understand the concept tremendously! Nice job 👍
Glad it was helpful!
Fantastic and comprehensive look at current plumbing best-practices. Definitely learned a thing or two for my home. Bravo!
Glad it was helpful!
For the first time, I had pleasure clicking the thumbs up 👍🏽 button.
Thanks!
Great post Great comments. Having lived with pumped water my life, every system has an expansion tank built in the pump pressure tank, usually 40 gal but I use a 60 gal cause bigger is better. Less swing, less pump cycles, less stress cycles...
One big perk of being on a well!
This has been an excellent video. Great explanations and demonstrations. I have always wondered why expansion tanks became common on plumbing systems. Well done!
Thanks!
Wow! What a great lecture and demo! Thank you.
Thanks!
Perfect interpretation of how important these tanks truly are.
Thanks!
Two comments from a retired engineer:
1. I can’t believe you were questioning whether the engineers were correct about the amount of water expansion with temperature. 😂
2. Even though I understand this principle very well, it is always fun to watch a good experiment. Nicely done. It is nice to see a tradesman who takes the time to understand the science involved in their trade.
Thanks!
Wow! By far the best video on expansion tanks on the web!!! Great job thank you very much for doing this and sharing
Wow, thanks!
This might be the best home systems video I’ve ever seen. Amazing demonstration, thank you.
Wow, thanks!
Plumber here- great info. I would like to add a technical detail. You actually want the expansion tank pressure to be just slightly lower than the static pressure by a pound or two. Reason- the diaphragm of the tank will slam into the internal body of the vessel when the first use of water after a period of hot water use and then non use- a shower and every one sits down and watches tv and create a noise similar to what we call water hammer.
This is especially evident on larger systems- 50 to 80 and more.
Hard to explain here , but trust me it happens.
We've done these this way for years and never heard of this before. We have incoming pressures of about 100-150 psi and regulate that down to 60-75 psi.
Had a number of calls during my career for random pipe noises. It was usually an oil fired water heater( they recover quickly) or an indirect ( Amtrol or equivalent) that would cause the problem. Oil is big up here in New England.
What happened was that there would be a large use of hot water, say just before bedtime and the first person up in the morning would get the noise- a loud thump and then it would not happen again until the conditions were right.
The pressure would build up to 100 or 120 and then slam back to the static pre- charge which is the neutral. By having the air pressure down about 2-5 psi, the diaphragm would not “ slam” into the bottom of the tank and make the “ thump”.
@@JTTTTx sounds like another issue going on. The expansion tank bladder moves as slowly as the water expanded in the video. Once compressed, when someone uses a tap, it will return to its static state fairly quickly but it does it silently.
Maybe where you are, but my area we have to install them that way. Maybe it was the first generation Amtrol St-5’s and ST12’s , but reducing the pre charge pressure to just under the static solved the problems , no more thump.
Maybe they added a suppressor like the Fluidmaster 400a toilet fill valve did awhile ago.
I've been in the hvac business for 20 yrs and had boilers with hot water element fail every 2 yrs leak and now it makes perfect sense thank you for your detailed info and dedication 😮
You bet!
Great explanation of the expansion tank and why it is needed. When I bought my 60 year old house a few years ago I installed a whole house filter system. Along with the filters I put in a PRV, which my house did not have originally. I found that the water pressure coming into my house was around 120 - 125 psi. I set the PRV to 60 psi and thought everything was good. A few days later my filters were leaking and the pressure had increased back to 120 psi after the filters. I thought the PRV had gone bad and the mfg sent me a replacement, the same thing happened. Then I did some digging around and figured out my problem was there was never an expansion tank installed in my home. I put one in and have since never had any issues. I recently replaced my 20 year old water heater in this house and found that the T&P valve was non functional. You would think that a home inspector would test these things when you pay them to check the home for issues before buying it.
There are a lot of things that the everyday person would think or hope a home inspector would check. But unfortunately they aren't as thorough as we would like them to be once we find something wrong with the home.
Many thanks. I'm a landlord of 20 properties and never thought it was important to spend the extra for an expansion tank. Guess I have work todo installing some expansion tanks! Very good video. Explained well.
Glad I could help
Depends on the local regulations(some require backflow preventors on all properties, some on just new, and some require install during renovation) and whether the properties have backflow preventors if on municipal water, or if on well water if it's one with a check valve to keep prime and no pressure tank(really uncommon)
If your water can go backwards and pass pressure past the supply then a expansion tank will really only help mitigate possible freezing issues where ice physically plugs the pipe and sends pressure into the house that way
I'm renting a house the plumber they sent out didn't even know how to test the system I found out that he's a apprentice plumber and works in rough install. Thank you very much for the effort. You are keeping me at JACK of all trades
Training other plumbers was taken into consideration when we created this video.
I am from south africa and thanks the video was very informative
Love to hear it!
Wasn't sure if I was going to watch the whole video but I am so glad I did. Best demonstration video in the history of ever! Thank you so much for the break down of everything. Amazing Job!!
Wow, thanks!
Fascinating; thanks for sharing. I didn’t know about the function of the relief tank - I thought it was to prevent water hammer.
Originally I didn’t have the pressure tank in my system. Last time I replaced the water heater, the plumber took it upon himself to add the pressure tank. Now I see he was a competent technician who kept up with best industry practice.
Exactly! They do help with hammer as well!
I have to compliment you on the demonstration of thermal expansion of liquid water. There is a shortcoming in your experiment in that when you turned on your heater and the thermo-expansion started it was in a limited volume space just taking in the volume of the water heater and the capped off pipes. In reality the volume with all valves open and the pressure would also take in the entire volume of the water system matrix from main water pump or reservoir to local source. Pascal's law would state the entire system in a static state would be equal throughout the system. In other words the volume of the water system would be able to absorb the 1 quart difference. Being a water system matrix would never be static there is someone somewhere drawing on the system depleting the pressure. Granted in a population of 200,000 and a family of 4, there would be 50,000 water heaters going off but never at the same time to raise the system to breakage threshold. (theoretical average). In my short plumbing career in the 80sI have never seen those pressure equalizing tanks used for that purpose. I worked at a Dept. of Defence safety group and the pressure equalizer tank was never brought up nor did we have one.. I do not have one in my house and in the 10 years I have yet to see a popoff ever pop or in any house did I see one pop off. Please note that the Mythbusters did prove that those things are a very necessary safety device in any system that heats water. After seeing a hot water heater blow the few dollars for such a safety valve is well worth the price. A bladder tank is albeit very useful if water hammer is present.
Cities are now installing check valves on the incoming water lines to prevent reverse flow back into their system. Also pressure regulation valves act like check valves as well.
This is the most lifesome lesson that I have ever learned in the industry! Bravo !
Love it!
Great video. I never had thermal expansion tanks on homes I owned or lived in near Chicago. I have one in my home near Dallas and had to replace it this past weekend when the old one sprung a leak. I enjoyed getting an understanding of its purpose.
Oh wow!
Absolutely awesome video. Many engineering courses teach this science, but you gave us a great visualization of this application in the practical world and you also demonstrated the things that can go wrong if you don’t address it properly with components like expansion tanks. You also showed what negative pressure can do to a thin walled cylinder (like a water heater tank) when negative line pressure / vacuum collapsed the plastic bottle. I know in some older cities in Massachusetts, you need a vacuum break on your hot water heater tank. As I’m told, if a fire truck starts sucking water from a nearby hydrant and you do not have a water line check valve in your home, then it could result in the collapse of your hot water heater tank, so awesome demonstration. Thank you for pulling this together.
Yeah I've seen pics of collapsed water heaters in high rise buildings that didn't have a vacuum breaker.
Good show. I have an old house with many old copper connections throughout. I just replaced my 1985, A.O. Smith gas 50 gal with the same make and size. What a difference this new one makes.
Even though I have an open system ( no backflow or check valve at the meter) your video has convinced me to install an expansion tank AND a supply regulator. The last thing I need is an old solder joint breaking loose in a 100 year old house. Thanks again
Glad we could help!
This is the perfect explanation. This guy could teach calculus to an infant.
Thanks!
I've taught apprentices in the past and your presentation is excellent! I have one tip and one question:
TIP - I've used something called a "bottle bushing", it's a plastic adapter bushing that you glue into a PVC socket and it uses an O-ring to seal the joint between the bushing and bottle, I've not used mine under system pressure but for my use it's been leak free. A simple google search will take you to the website where I got mine from.
QUESTION - Can you mount the expansion tank above the system piping (essentially up-side down) to help with system drain down i.e. when closing and winterizing a cottage for the winter?
Thanks for the tip!
Yes expansion tanks can be installed in any direction. Some have commented on here that they prefer installing them on the top of the pipe so sediment doesn't build up in them.
Historically, this wasn't an issue in municipalities. What has happened since is that the water companies have installed new meters that are 'tighter' internally. The excess pressure from residential WH's formally used to travel towards the city's meters and beyond. This caused them all kinds of issues on their pumping side. Now, the excess pressures can no longer pass into the city systems. However, residential customers didn't understand why their T&P valves were suddenly seeping/leaking one day.
And in the beginning, when this started to be a problem, municipalities were silent to the plumbers and the public about what was happening. I remember this well. Now it's common knowledge, but it wasn't always so. The municipalities didn't want to be blamed for leaking, in house HW services when all they were doing was protecting their pumping stages/equipment.
Also the EPA started requiring more check valves in the municipal water system. Those check valves help ensure that water only leaves the system and can't return.
@@SmedleyPlumbing Yes, I see this a lot in municipalities now; check valves right against the meters. Required too if you have a separate meter for irrigation as a fight against back-siphonage.
@@TheReal1953 yep. And thus the need for more thermal expansion control.
Thanks for showing this, and God bless you!
You are very welcome
All of the work I do is applied physics. I do commercial HVAC. This was a good demonstration. Thanks for helping those kids to get a clue.
Glad it was helpful!
This is really a "compression" tank, not an "expansion" tank. There's a difference. The compression tank compresses the trapped air in the tank, separated from the water by the diaphragm, while an expansion tank is open to the atmosphere. FYI 🤔
I see where you can think that. However, you'll never find one by calling it a compression tank. The code book doesn't even use that terminology.
Wow! A rare and great lecture by a plumber who knows the "how" of the trade and also understand the "why" of the theory behind it.
Would love to see you shine some light on how to properly charge a thermal expansion tank. Is the factory charge of 40? psi good for all residential houses?
We could do a video on that soon!
1. Measure your water pressure
2. Turn off water to the home
3. Remove existing expansion tank
4. Using a tire pump, air up new tank yo match water pressure.
5. Apply thread tape and or pipe dope to threads.
6. Install new tank
7. Restore water service making sure to open faucets and flush toilets to bleed out the air.
@@SmedleyPlumbing I'm just a DIY-er but last time I installed an expansion tank I installed it then measured the pressure then closed the inlet valve of the water tank itself and left a hot water tap open in the bathroom. I simply aired the tank to the correct pressure then turned everything back on. I think it's faster/easier than shutting the main valve off :)
@@balint133 yeah that works also. The most important thing is that you are airing up the expansion tank without water pressure pushing against the other side of the bladder
@@balint133 how did you come up with that on your own? 😊
Great video on Thermal Expansion tanks.
Thanks!
Excellent demonstration - Thanks
Thanks!
Shame shame, First of all you did not tell all your viewers weather or not you were on city water or well water or if you had a pressure reducing valve on your city water and you know what a difference that would make The only time you would need a expansion tank on a hot water system other than a heating Boiler is if you had a closed heat system. When you are connected to the city water there will never be a pressure rise from a water heater heating up because it will expand to the city water system and if you were connected to a well system you would have a well expansion tank on that also, which will also work for the heat expansion of the water heater heating up. In most cases dam near all you will not need a expansion tank on your water heater. Waste of you money.
If only you were correct. Aside from being required by code, they are more commonly needed and not.
Why do people rant like this about things they don't fully understand. "Shame, shame..." 🤦
And it's, "whether," not, "weather."
I have lived in 4 homes in modern suburbia with many water heaters…. And never had an expansion tank.
That was cool I never thought about how hot water exploded WOW just all common sense
😅😅😅
Yep!
Well said SIR.
Thanks!
One of the best educational videos ive ever seen on youtube. You explained it perfectly sir. If only my highschool teachers would of had your teaching skills. Or possibly I wasn't paying attention back then. Thank you for the great lesson.
Glad it was helpful!
One of the best no-bs demonstrations I've watched on youtube to date! Very well done, thank you!
Glad it was helpful!
Loved your comment about AZ cold water temp... I'm in Tucson and during this summer (2023) there were a couple weeks where the cold water was warm/hot enough so that my showers didn't need any hot water...
Yep. You get hot or hotter. Lol
Great science hydrology class as well
Glad you liked it
Really explained the purpose of a thermal expansion tank. Fine job.
Thanks!
great representation of a expansion tank, you made it all make sense. Great video, thanks for your time!
Thanks!
Holy smokes that was one of the best demonstrations I've ever seen... thanks you so much for that brilliantly detailed example!
Wow, thank you!
perfect explanation! Our home has 30lb city water pressure and we have never had a water pressure release(knock on wood) Our last home had city pressure that could easily have 120psi without a pressure regulator. Those regulators didn't last long and you could hear neighbor's regulator failure with loud whistle/groan
Thanks!
Great work sir - my dumba** thought it was just for a few more gallons for last 12 years. lol
Lol
Thank You for nerding out on this! People don’t understand this stuff but definitely need to understand that
It's very important. Especially if you're trying to make these sales to customers.
Very good video explaining the purpose and how the thermal expansion work. My only "silly" suggestion is to chance "water creation" to "more volume" . The mass of water doesn't change but its volume. Thank you
Great point!
Thank you! Amazing video and example 👏🏽 👌🏾
Thanks!
Great, great explanation of how expansion tanks work. Love your video and how detailed it is explained. Clearly visualize with the gauges and simulated scenario in real time. Thanks for share your knowledge and experience. Today I learned more!! 👏👏
Glad it was helpful!
Good stuff. Going to use this to show the people I train.
That's part of why we made the video. It's a great training tool!
One of the best demonstrations I’ve ever seen. Very well done!
Thanks!
The best video explaining thermal expansion tanks and water heating functions! Excellent work!
Glad you enjoyed it!
Hi from north of ya -Iowa- the way you speak so humbly makes me feel more thankful that I am in the right trade . Wish I had more time to work out a plan to work for myself and make people happy . Raising 4 kids takes lotta time away for things you wanna do and venture !
Keep it up boss !
It's a great trade to be part of!
Absolutely fantastic video. Extremely helpful
Great to hear!
That is the most understandable explanation I have ever seen to express the need for expansion tanks on water heaters. I appreciate all the visuals you used to demonstrate what is really happening inside that water heater. Awesome job.
Thanks!
What an amazing job explaining things such a clear manor. Great teacher! Thank you
Thank you!
Very simple scientific demo for layman to understand water preasure snd relief tank. Thanks.
You are welcome
Awesome demonstration. Thanks for putting in the work on this.
Glad it was helpful!
Good visual presentation
Glad you liked it!
I learned a lot from this video. Thanks a lot for putting in the effort to educate everyone on this important topic not many people pay attention to
Glad it was helpful!
Excellent demonstration. Well done!
Glad it was helpful!