What does an expansion tank do?

In today's video, we talk about the importance of having an expansion tank installed on your water heater. These tanks are very helpful in extending the life of your water heater by keeping stress off of the water heater tank. At Walley Plumbing Company llc., we know how important expansion tanks and we've seen first hand the effects of not having one. Protect your water heater and your home from damage by having one installed. If you live in the Mobile, AL area we'd love for you to call us! contact us @ 251-554-9221 or online @ walleyplumbingcompany.com

[@elirocha8548]

I bought this water heater kzbin.infoUgkx8G49mV71sAzUl9shXyLW-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.

[@thomasluker9434]

I always wondered about expansion tanks. This video really helped me understand how they work, without me asking someone how and embarrassing myself amongst my peers. Thank you Tony, once again, for helping my sound smarter than I am when I talk to people about plumbing

[@walleyplumbingcompanyllc5188]

Any time Thomas! Thanks for watching and asking! That's how we learn!

[@keahi7646]

Thank you, I never knew this timely information.

[@damancarlos]

Good, informative video. Thank you for posting it.

[@howardk1356]

Great video. You answered all my questions. Thanks!

[@walleyplumbingcompanyllc5188]

Thank you so much. What part of the world are you in?

[@jeephoffer758]

Thank you for explaining this

[@walleyplumbingcompanyllc5188]

Thank you for watching. You’re welcome.

[@lutronc4412]

Also helps take pressure changes off supply and lines. If you have a recirculation system...

[@jklwjk]

Thank you.

[@philthebarber]

Excellent! Come to Boston to install one for me.

[@walleyplumbingcompanyllc5188]

Man I’d love to! It may take me a while to get there though! 🤣

[@draxxgaming7981]

lol i just put them in because im supposed to. glad this video exists

[@crod279]

I’m no plumber but I’ve never used one and have never had any issues. By the time it goes bad I just replace it. These things are design to go back the day after warranty is up anyways.

[@1986subway]

How do your heaters usually fail?

[@walleyplumbingcompanyllc5188]

We've had several instances in which the water heater liner fails and begins to leak. In each instance, there was no expansion tank. So i think they have great value. Thanks for commenting, where are you from ?

[@timgaskey2258]

If they were needed they would be designed with them already on them, sometimes people just look for things to put on things that aren't needed.

[@stevebabiak6997]

@@timgaskey2258 - no because there are some installations that don’t need an expansion tank, they aren’t incorporated into the water heater by default. Also, a water heater has a much longer service life than an expansion tank, so water heaters would have to be replaced far sooner if the expansion tank was built in. The real point that was missed in the explanation is when it’s absolutely a must to have an expansion tank regardless of what code requires. If the water meter has a back flow prevention device, then an expansion tank is a must. If the incoming water supply uses a pressure reducing valve, an expansion tank is a must. If the T&P valve on the water heater is dripping, you might (might means maybe, not must) need an expansion tank. The water expansion that occurs when the water heats water is sometimes released by plumbing fixtures - for example, a toilet that seems to run might be doing that because it the increased water pressure that the expanding water produces in an otherwise closed plumbing system.

[@jballs1118]

Great video sir i have a question i have an AO smith gas water heater and for decades i had never install an expansion tank. When the heater goes bad it start leaking from the bottom and i just replace it. Should i get an expansion tank?

[@bobbysmith3196]

My water heater has two different sets of water hookups- Two on the lower side and two on the top... possibly for the type installation... I’ve hooked it up to the ones on the lower side connections and now need to add an expansion tank. Does the expansion tank have to be hooked up to the cold side that is actually supplying the water heater or could i just hook it to the extra (non-used and plugged) top cold hookup? Would just make the job a LOT Easier and should let the thermally expanded water press out of the heater. Thanks in advance for Any Advice!!! Great video btw-best I’ve seen yet 👍

[@daTERRORIZER]

That anode rod looks like it has never been changed.

[@walleyplumbingcompanyllc5188]

Thanks for the comment! You’re right. We had just purchased this building during when we did this video. We installed the expansion tank and then we changed the anode rod. We did a video on changing anode rods so we don’t do another one. You’re pretty observant.

[@daTERRORIZER]

@@walleyplumbingcompanyllc5188 Observant....hmmm maybe but "pretty"......you are way off. ;) Keep up the fine performance.

[@walleyplumbingcompanyllc5188]

Leonardo Medina 😂😂 Thank you sir. Stay safe out there!

[@tino4414]

i have a solar heater whistling badly. seems it is doing that from ceck valve in cold pipeline. would it eleminate the noise, if installed an expansion tank?

[@joegabriel6001]

Does this solve water hammering issue in the house????

[@SuperDagod1]

will this tank stop the thud, thud, thud water pressure noise inside the house when someone turns on the shower?

[@positivevibrations.4607]

Should the pressure tank keep on or off??

[@shawnsg]

We just bought a house and the water pressure is super high. It peaks around 130psi lol. I think I need to install one of these and a pressure reducing thing.

[@walleyplumbingcompanyllc5188]

Yes its called a pressure reducing valve. Our local suppply house carries them in 3/4" and 1"

[@ranger178]

the city might provide one they do where my brother lives his pressure is crazy high if the pressure reducing valve fails stuff blows up like water softeners and things at his house.

[@veganwally]

3 to 5 yrs., mine is 11 yrs. old and still holds 40 psi. Great video.

[@walleyplumbingcompanyllc5188]

Nice! What brand is it? I may need to start buying them!

[@veganwally]

Mine is a "American" water heaters portable water expansion tank 2 gal. #318461-000

[@mrfisther]

My tank is 16 years old, without expansion tank. Never had a problem.

[@adambomb13]

@@mrfisther Same here my system is a Rheem Fury 18yrs old and NO expansion tank, but it is being replaced today without an expansion tank :)

[@abrahamsterbenz6497]

Home water pressure can increase up to 10psi over normal when served by a tank water heater. Heat expands water. Be sure to read pressure while the cold line is isolated.

[@jimmoore6033]

My water pressure goes up to the supply line pressure of 140PSI when our hot water heater turns on, I only have a PRV installed. I will install a Watts 2.1Gal Thermal Expansion Tank this week to keep our water pressure about 50PSI which is the PRV setting.

[@dantesamson2570]

Thanks for the great video. Question: When water is on, we hear hammering noise inside. Water pressure off the water heater drain valve and off the hose bib outside reads 80psi, but inside (wash room) is 38 psi. could be a faulty prv and or expansion tank?

[@ranger178]

there could be a pressure reducing valve in your plumbing system.

[@skiboskeeskiblets]

Just replaced a 20 year old gas water heater, never flushed it, never changed the anode rod, and didn’t have an expansion tank…connected to city water…I replaced it because it was not heating as it should, probably from sediment build up….im sure these tanks are helpful depending on your situation…I didn’t install an expansion tank on my new one…I didn’t have a logical reason too

[@Alex-qe2lf]

Do you need a dielectric union at the ET inlet since it is SS and it comes in contact with dissimilar metal (copper)

[@ranger178]

if it is actually good stainless it should not corrode too much when connected to copper

[@markthibault6551]

Thanks for the great info I would just like to say Untill they made building codes that forced you to use mechanical air hammers instead of the manual style. That we used for years You didn’t need a thermal expansion tank. My opinion

[@ranger178]

you only need expansion tanks in places with pressure relief valves in your house with a backflow preventer that keeps water from being sucked out of house if city pressure goes down like water main break. if you have no backflow preventer the water just expands back on the cold-water supply line a few feet

[@nigelmansell8864]

Can these be installed on the hot water line I’ve seen unvented cylinder in a cramped cupboard before with no balanced cold so just hot pipe leaving cupboard and it was teed in there

[@walleyplumbingcompanyllc5188]

It needs to be on the cold side.

[@marcostudd]

You mentioned "other things you can maintain" or upkeep.. in order to expand the life of the water heater.... what would those things be? I already got this down... also the Anode Rod.. . what else? TIA

[@PowerfullProduce]

Dielectric unions

[@lexbrusb.1821]

if you have open water system (i.e. no check valve in the cold water inlet), then you don't need expansion tank, since the excess pressure will just go back to the city main. Am I correct?

[@javarithms]

By the same logic what's stopping the excess pressure from the city main to put a strain on your pipes?? Expansion tank is like insurance, you hope you'll never need it but will be glad when you do.

[@edgarsanandres3053]

Do the pressure relief valve and the over flow pipe the same function?

[@rsan3829]

Yes

[@MichaelJohn-qm4ri]

What does an expansion tank cost in canada

[@fittingitinllcRVA]

Plumber who installed out heater said it wasn’t needed but we are in city water which I am sure has that no flow back gauge. Coarse that’s what I get when ur LL calls a half ass company to install.

[@cheerry777]

Sacramento has that requirement. But still don't know why it's necessary besides it being very important.

[@walleyplumbingcompanyllc5188]

It really does help to extend the life of the inner liner of the water heater. The heating up and cooling down really puts stress on it over time if there is no air cushion to help it out. I used to feel like it was a waste of time to install one but not anymore.

[@cheerry777]

I see. Thanks for replying. They shouldn't make it a requirement.

[@silentlessons4221]

are these helpful in situations where my water pump keeps starting every 2 minutes even without anyone opening the taps? I do hv a geyser and could be the heat causes the pressure to fluctuate?

[@walleyplumbingcompanyllc5188]

They are mainly for accommodating thermal expansion. Your problem sounds unrelated to an expansion tank to me. Thanks for your comment. Where are you from?

[@WireWeHere]

If you have a well and your pump supplies all the pressure for your system then you need tank to go with it. The expansion tanks are just a smaller version of your main pressure tank. They both put a compressible fluid inside a system of the incompressible. Without an air bladder of some kind when you draw off a tiny amount of water the system's pressure drops dramatically. The air bladder or volume is a cushion or spring to push back on the water as its volume changes. You're correct in thinking that adding an expansion tank might help with your pump cycling too quickly. What i suspect is your main pressure tank either doesn't have a bladder inside (old tanks) to physically separate the water and air or the bladder is damaged and allowing water past. If you have an old tank its normal for the air to hide as bubbles and escape slowly out a tap. Regular maintenance includes draining the tank once a year to both remove sludge and also to restore the tank's air volume. That air volume is your pressure buffer. Hope that's enough and always happy to help if I wrote something confusing. Nothing like running a few months behind, nobody's watching by then. Another possibility is a slow leak somewhere. The final one I'll add is the pump's pressure switch. The switch needs to have 10 to 20 PSI of pressure difference between cut out and cut in. Sometimes its fixed by the switch design and other times its adjustable. Best of luck under pressure.

[@benv9711]

I've never seen one in NC, MI, AZ or CA

[@JoseRodriguez-hx6wk]

Good advice. Simple instructions to follow. May save you money in the future. Thanks 🧰👍

[@Miketaylornews]

I have a Watts (adjustable) relief valve coming from cold water line and is set up to release outside like the water heater pressure relief valve... And it's leaking ...the stupid part is so old Home Depot doesn't even have it you have to order it.. Something tells me this is just a pressure relief valve they used before they used the expansion tank and it's totally unnecessary now. But finding the answer to this question on the Internet is like almost impossible I've been trying for 4 hours can't even see straight

[@jimsumner7360]

If you’re on well water does the expansion tank at the well serve the same purpose

[@ranger178]

as long as there is not a backflow preventer or pressure reducer to keep water from going back out of heater on cold side.

[@number1diamond]

Quetion: If you change the pressure on the PRV, do you need to recheck the pressure on the expansion tank?

[@walleyplumbingcompanyllc5188]

I would

[@jacobcarraway1989]

I just installed a PRV with a valve box coming off my meter. I set the water pressure at 55psi and checked with a gauge to confirm at the hose bib. I then installed a Rheem water heater with a watts expansion tank set at 55psi. If you change the pressure at the PRV, buy a gauge to test on a outside hose bib. This will be the new pressure to set on your expansion tank.

[@jeffjohnson2792]

Thanks. feeding the algorithm...

[@walleyplumbingcompanyllc5188]

Thanks for the comment!

[@tty3146]

I have 2 heaters and each has expansion tank on cold side. my system pressure is 60 psi. One has 55 psi and other has 75 psi. Is this acceptable? bad?

[@ranger178]

is that pressure of air in the expansion tank you mean? it should match your system pressure, or it won't really work right.

[@DavidFlores-du3rm]

Would this make my water meter at street to turn when water is off? I can’t find any leaks in house so trying to figure out what’s causing meter to turn.

[@walleyplumbingcompanyllc5188]

It's not probable. If your house is on a slab you could have a leak under the house that hasn't surfaced yet. Those are common where we live. Most common for us is a running toilet though so be sure to dye test your toilets before taking more evasive measures. Hope this helps.

[@DavidFlores-du3rm]

@@walleyplumbingcompanyllc5188 my house has a valve to turn off water inside home so I trun off wait few mins and noticed the meter at street still turns slowly.

[@anthonyfarone420]

Just had my expansion tank changed and the old tank was leaking from rust or something. The actual wall of the tank rusty or something. Not leaking at the threads, but from the wall oc the tank. Ever hear of that?

[@walleyplumbingcompanyllc5188]

Yes. The bladder inside of the expansion tank probably ruptured

[@anthonyfarone420]

And then a pin hole created from the rust. Ugh. Thanks

[@thisguyhudson5995]

My pressure is about 85lbs. Is this safe to pump to?

[@natepeterson7145]

Most codes are 80 psi according to another KZbin video that's a plumber.

[@bobgerle5937]

If you have a well, you have an expansion tank on your main supply!

[@fstopPhotography]

We have a new build house with a well. We have a pressure tank that keeps the water pressure at 50psi. We dont have an expansion tank on our water heater. It's not required by county code. Should we honestly have one?

[@angeldetierra3855]

-- No. If you are getting city water and the water meter has a backflow prevention valve, You need an expansion tank. or if the incoming water supply goes thru a pressure reducing valve, You need an expansion tank.

[@fstopPhotography]

@@angeldetierra3855 Thanks

[@anthonyhitchings1051]

they last 3-5 years - to heck with that!!

[@tiffanysgottimetoday4589]

I don’t have one of those on my water heater

[@walleyplumbingcompanyllc5188]

Might be a good idea to get one.

[@tomclose390]

how do i know its bad?

[@walleyplumbingcompanyllc5188]

You can remove it and drain the water out of it. Then try to pump it back up. If it doesn’t hold air pressure the bladder has failed

[@joevignolor4u949]

If you install the expansion tank upside down like in the video won't you end up with air on both sides of the bladder because air is going to get trapped in the wet side of the tank? Shouldn't the tank be right side up so there is only air in the bottom of the tank and only water in the top of the tank?

[@walleyplumbingcompanyllc5188]

To our knowledge, you can install it up or down or horizontal. Always read the instructions for each one though.

[@javarithms]

Air compresses, liquid doesn't.

[@u2ooberboober]

Isnt ther a bladder in it that separated the water from the air?

[@joevignolor4u949]

@@u2ooberboober Yes. But when the tank is first installed it will initially be completely full of air on both sides of the bladder. Then if the tank is upside down (wet side down) when you turn the water on the wet side will only partially fill with water because air will get trapped in the tank on the wet side. But if the tank is installed wet side up the air will purge out of the tank as it fills and the wet side will be completely filled with nothing but water. That's the difference depending on whether the tank is installed right side up or upside down.

[@u2ooberboober]

@@joevignolor4u949 I see what you’re saying now. Eventually that air on the wett side will be dissovled into the water and only water will be present and fill the space.

[@WireWeHere]

Thermal expansion happens when heat forces water molecules to demand more personal space. If we don't give the water molecules a place to go they will start pushing and shoving on each other and on their tubular prison maze. This will cause an increase in pressure unless there someplace to go like a shiny new expansion tank. Now since air molecules are trapped in the expansion tank it acts as a hydraulic accumulator and all the air molecules move closer together as water moves in. This does result in a very small pressure increase that's hardly worth mentioning. Essentially the expansion tank is an energy storage vessel that controls an unwanted pressure increase in an incompressible fluid, water, by compressing another fluid that is reasonably happy giving up a little real estate. No time for proofreading so please auto repair any typos or factual omissions. Although commonly installed near the water heater this is out of convenience. An expansion tank can be placed anywhere on the home side of the cold water unless your local code says otherwise. It's adding protection for your entire system. If you have grey or gray Poly B by Yuleki an expansion tank can help you walk that fine line of procrastination. Bye

[@walleyplumbingcompanyllc5188]

Jim Marriott thanks for the info!

[@mickeyromero9233]

That was a great way of explaining it. Id really like to understand plumbing from this kind of perspective. What are your sources, if you dont mind

[@stevenschrock]

Ok now cut the power and make it 0 degrees for a week air molecules also crystallize and in the deep freeze that things are ticking time bomb

[@kertrowlins3954]

I have no water heater all I have is a expansion tank. Now the release valve is always leaking I'm thinking the bladder is not good anymore. Oh I also put a pressure gauge on tank it's not reading any pressure at all?

[@psychobill3646]

great videos. hey got a question though, flushed my tank out then the pressure valve started leaking. replaced the valve and the new one started leaking, not sure on our water pressure but it sure dont seem like itd be that great. should i get an expansion tank either way?

[@psychobill3646]

another question, when i emptied tank had the hot side on faucet open water still came through as if some idiot crossed the cold with hot somewhere under house or is that the new days yahoo faucet invention?

[@walleyplumbingcompanyllc5188]

Hey Bill and thanks for the comments. I’d say you need an expansion tank either way. You also may want to look into a pressure reducing valve installed on the water service line of the pressure is too high. You can buy a gauge that screws onto your outside faucet to check the pressure. Those gauges aren’t expensive at all, less than $20. Normal house pressure where we live is around 60 pounds.

[@u2ooberboober]

@@psychobill3646 sounds like you had a cross over within a mixing valve style faucet.

[@psychobill3646]

it was an older shower faucet causing the crossover. but still our hot water tank drips (new) and our pressure is only at 64psi

[@ranger178]

does water come out clean or full of hard water deposits and rust could be just dirt keeping valve from seating did you open the new valve after putting it on tank? you might have stirred up dirt and clogged the new one.@@psychobill3646

[@ranger178]

you only need an expansion tank if your plumbing has a backflow preventer or pressure reducing valve older homes lots of times don't have them, so the water just expands back into the supply line a couple feet as tank heats up nobody requires them where I live or has one in their houses.

[@walleyplumbingcompanyllc5188]

Yeah that’s right. We have check valves on our water meters around here.

[@scottjohnson676]

Yah, and the looks I get when explaining why our government thinks this is necessary while I remove their 25-37 year old water heaters. I can't explain why its desirable to put on the cold water side when the hot water is expanding and the entire water system is connected and not isolated hot from cold.

[@walleyplumbingcompanyllc5188]

That’s a great point. Our inspectors make us put them on the cold side

[@joevignolor4u949]

If you put the expansion tank on the hot water side then some hot water is going to be forced into the tank as the water heater heats the cold water coming in. This will cause the expansion tank to become hot. Because the expansion tank is not insulated like the water heater you are going to lose some of the heat from inside the expansion tank out into the room. It costs money to heat the hot water so losing some of the heat out through the expansion tank makes the system less efficient and more expensive to operate. In other words the expansion tank becomes a source of heat loss that will allow heat from the hot water to escape. But if you put the expansion tank on the cold side then this cause of wasted heat is eliminated.

[@ricos6243]

Goes on cold water side?

[@walleyplumbingcompanyllc5188]

That’s what our inspectors in alabama require

[@ricos6243]

@@walleyplumbingcompanyllc5188 Thank you

[@keepitreal829]

38 years in the trades with hundreds of rentals never put one on . No issues

[@walleyplumbingcompanyllc5188]

It’s code around here. We don’t have a choice. If you’re a donor your seller, things will work for years. That doesn’t mean they are working properly. Good luck with it.

[@keepitreal829]

@@walleyplumbingcompanyllc5188 keeps me employed as well and my kids.

[@ctaylor7089]

Expansion tanks aren't necessary unless there is a backflow preventer on the water supply.

[@walleyplumbingcompanyllc5188]

We have closed systems where I am. Water meters have check valves on them

[@aaronkuntze7494]

It's all fun and games until you file a water damage claim with your insurance company, and they turn you down for code violations. I am a retired plumber (30 years) And a licensed plumbing inspector who works for the insurance industry, i can tell you my employers loves hearing "improper installation " from me. Can you say denied?

[@Master-iv4vj]

While I agree with the video creator on the topic, I just bought a house with 1988 Kenmore Power Miser 5 gas water heater in it. No expansion tank, 1/2" pipes for cold and hot installed on 3/4" fittings, but it still works and no leaks. Mystery...

[@walleyplumbingcompanyllc5188]

It’s awesome to see the exceptions to the rule. We got a call from a customer that said he had a 30 year old Montgomery Ward water heater and was asking about replacement. He said he was going to let it ride a little longer just to see. He hasn’t called back and that was about 5 years ago.

[@bakaslim1022]

Can a bad expansion tank cause the water to be hot on both sides of the lines?

[@MrMblaze8597]

No you have a cross connection somewhere

[@walleyplumbingcompanyllc5188]

Not that I know of. if you're talking about lines hot to the touch on both sides of the heater, that's pretty common and had nothing to do with the expansion tank.

[@walleyplumbingcompanyllc5188]

I agree. A very common one we've seen I when a remodel is going on and a new shower valve is installed with out the cartridge, only the temporary cap, during construction. You have to install the cartridge on the top out in these situations when the home is occupied to avoid this mixing. You'll get a call for sure to come back and fix it! What others have you seen to be most common?

[@MrMblaze8597]

@@walleyplumbingcompanyllc5188 Yeah you have to put that cartridge in for sure. I have never seen that one but that would 100$ do it.

[@robertlyman9789]

Dip tube broke inside tank

[@rss608]

If you are on a well with pressure tanks you don't need an expansion tank unless you have a check valve between the tanks and your house. pressure tank is on the cold water side is correct. I located mine under my kitchen sink, on the cold water side. It doesn't have to mounted on top of your water heater. could be any where on the cold water line in the house in front the water pressure regulator if you have one. Just a couple of flex hoses and a water T can make mounting and installing and servicing the tank, easy. Plumbers like the water heater mount because they get paid for changing the plumbing. they do keep your pressure valves from leaking.... Gotta use your brain people....

[@walleyplumbingcompanyllc5188]

We like installing them on the water heater because it’s the most efficient place to put one. We don’t have many customers that want to give up cabinet space under their kitchen sink for an expansion tank. Also, the water heater is also the most convenient place to access a 3/4” line, which is what the expansion tank calls for.

[@icyhot4663]

👍

[@eddieramirez121]

OK Walt Disney tell me a fary tale.

[@eddieramirez121]

THIS SHIT AND OTHER HAD I HAVE SHINOLA

[@cornellsmith5895]

That's not even how my water tank failed it was a bad thermocouple and ignitor and it was irreplaceable so the whole expansion tank I'm gonna call bullshit don't do it unless it's to pass an inspection.

[@MB-zk7pz]

Long story short...its better to have the expansion n contraction to be going on in the expansion tank rather than the water heater.

[@walleyplumbingcompanyllc5188]

Absolutely

[@jtroi5523]

Please stop repeating yourself

[@jerryjones1688]

What a joke! It’s useless

[@rodeoclownobama5796]

what happens is the new tank heat up so fast and steel is thinner, this make the steel expand and contract, this cracks the porcelain coating, once that happens the tank rusts out in no time .

[@walleyplumbingcompanyllc5188]

Good insight. Thank you for the comment!

[@rodeoclownobama5796]

expansion tanks have to installed horizontally, that's code

[@walleyplumbingcompanyllc5188]

Thank you for the comment. That's not code where I am.

[@rodeoclownobama5796]

@@walleyplumbingcompanyllc5188 ok I'm probably wrong on code . that's what the old guy said at water heater dist.where we get our tanks and that's all they sell. so I dunno. I looked it on the internet, the net said doesn't matter how. sorry I can admit my mistakes. have a nice day :)

[@walleyplumbingcompanyllc5188]

@@rodeoclownobama5796 we’re all in it together brother. I don’t know it all either.

[@joegabriel6001]

Does this solve water hammering issue in the house????