hey guys good morning Roger Wakefield here the expert plumber coming to you to
answer the question today how do water heaters work now believe it or not we
get that question a lot because people want to know what causes their well how
does it work what causes it to go bad what causes it to quit working but the
thing is first of all you've got to know how it works so we're gonna start out
with gas water heaters gas water heaters have natural gas that come in they've
got a burner box below a tank most tanks in Texas or most tanks around here are
probably 50 gallons there's some as small as 30 and 40 and as large as 75 80
a hundred gallons but those are mainly commercial installations today we're
really going to talk about residential let's just talk about a 50 gallon gas
water here so you've got a burner assembly on the bottom you've got a tank
above it that actually has a flue pipe right in the middle or a flue and the
heat goes up through there the burner assembly puts the fire right around the
bottom of the tank and guys I've been to Bradford White's training facility and
are not just a training facility with their manufacturing facility and it's
it's really interesting to watch it was such an amazing experience to see how
they put these together and the quality control systems gone through but the
burner heats up the bottom of that tank it's just like putting a pot on a gas
stove he's at the bottom and that heat rises now you've got a gas control valve
there that also works like a thermostat to tell the burner assembly when to kick
on when not to kick on that has to be changed out sometimes a gas control
valve sometimes a burner assembly can have to be changed out you've also got a
thermocouple a thermocouple is a great safety device and that's just one of the
safety devices there your thermocouple goes in to where your pilot light is and
your thermocouple is what is actually there that that fire is burning and what
that does the heat sends a little microelectronic signal back to the
control valve to let it know look there is fire in there and that way when that
gas control valve opens and sends all that gas in there to heat your water and
you hear that big woosh what happens is or what happened is the gas control
valve sent a signal to let it know look it's okay it's a safety switch so you've
got your thermostat set hot it burns everything's good
once it heats up to whatever you've got your control valve set what what
temperature you've got it set at then it'll cut back off and when it cuts back
off that pilot light keeps burning as long as that pilot lights burning you
don't have any problems because every time your water heater calls for gas
it's gonna go off now out of the top of water heaters your flue pipe your flue
pipe needs to be unobstructed it goes all the way through the roof and what
that does is that gets those gases those the the burnt natural gas gets those
fuel fumes out so that we don't smell them so if they don't kill us you know
burn gas and good so that's how a natural gas water heater works by
heating the tank just like a pot of water there's a lot of different things
that go through the system to make it work but the the very simple components
are the burner assembly at the bottom the control valve and then really the
only other thing you got is your TMP valve now I mention to safety pieces
other than your thermal coupling you've also got a high limit switch that's down
in your burner assembly and if it gets too hot dinner this thing will kick off
and shut your water heater down but again it's a good thing to have there is
a reset button on it that sometimes you can push right in the middle it may have
accidentally triggered there could be something wrong but guys always check
that out that's one of the first things a good plumber is going to check out so
that's how a gas water here works now let's talk about electric electrics are
a little bit different you've got 240 volts coming in the top
so you can open up the lid there on the top stick a voltmeter in there
and see what your volts are to make sure you've got what you need from there your
electrical lines go down they split off two thermostats and then go to elements
your thermostat tells the element when to kick on and when to kick off your
thermostat checks your temperature at the top and bottom some water heater
types or the way there they're wired or set up both elements may kick on at the
same time or they may go one and then the other or it may just go about what's
needed in certain areas of the tank so the big deals about electric water
heaters are the things that can go out are your heating elements and your
thermostats now again you have a TMP valve on top of it just like the gas
water heater it's a safety limiting device if the temperature in there gets too
hot the pressure blows out and it's set to relieve that pressure that way your
tank doesn't explode if you ever have a handyman work on your water heater and
he tries to plug that line tell him no that is not a good thing so your
thermostats check your temperature you've got a little dial indicator on it
to where you can set that temperature manufacturer recommendation I believe
some 120 degrees some people like their water a little bit hotter so they'll
crank it up but remember if you've got kids in your house guys don't turn it up
where they can scald themselves that that is not something that's going to be
good for you for them or anybody else so the water has a dip tube comes in the
bottom your elements heat it up and that dip tubes also on the hot water I mean
on the natural gas hot water heater the water is it heats Rises so when you draw
hot water out of a water heater it comes out of the very top thanks to Bradford
White again I've got a couple of water heaters back in the shop we're gonna set
up and do some videos and I'm gonna actually show you all the inside of a
water heater a lot of people have never seen the inside of it I know a lot of
plumbers that have never actually seen the inside of a water heater and I've
got a gas on electric so I'm gonna be able to show you both you can come in
and it's a whole other video but you can come in and check your thermostat
like I said you can take off the top you can check your volt with a voltmeter and
determine your power to the water heater if you've got an electric water heater
it's not working that's always the first thing to check so check your electrical
coming in check your thermostats I check your heating elements you can check
everything there and find out what's wrong with yours if it isn't working but
that's how they work they kick on they cycle they keep your water hot now we're
going to get into tankless water heaters tankless water heaters are quite a bit
different number one sorry about this guys number
one that they don't have the thermostat in there they don't need it because
they're not trying to maintain a certain amount of hot water what they're doing
is they call for hot water on demand so they got hmm they've got an indicator
there that literally determines flow rate so when you call for hot water
somewhere in the house this indicator the switch kick zone triggers the burner
assembly and water goes through the heat exchanger now whether it's gas or
electric there's either heating elements or there's a burner assembly that heat
up super hot a natural gas water heater has a tank type has runs on 40,000 BTUs
there about a tankless water heater draws in one hundred and ninety nine
thousand BTUs they don't go over 200,000 because then it would be considered a
boiler so you've got five times the gas heating and trying to heat water in this
narrow pathway and the more you turn that thermostat up what it does is it
slows that water down that water heater stays in that heat exchanger longer so
it can get to a hotter level so if you crank your thermostat up to 140 degrees
what's happening is you're slowing down the water through the path you slow it
down it heats to a higher level there's so many things inside of a tankless
water heater to make them safe they've got fans to exert to vent out
the air exhaust the vent or exhaust the gases they've got fans
that kick on before it even fires up you've got all your gas burners in there
you've got your expansion tank you've got chambers in there guys
tankless water heaters are fantastic they're great ROI investments you'll
you'll make your money back by what you save I'm not heating a tank full of
water and keeping it hot all the time the thing is a lot of times you may have
to change your gas you may have to change a lot of things to get to it or
to make it happen when I say get to it you may need a larger line to get to
where your other tank water heater was in order to increase the amount of BTUs
you can get so tankless water heaters tank water heaters guys it's a great
process it's a great system it works really well
there's also solar there's geothermal there's a lot of different kinds of
water heaters that you can get those are the probably the three most popular
types that we deal with here any other question that we get asked like this is
like a bonus tip is there anything I can do to make my water heater last longer
guys absolutely if you've got a tank type water heater flush it at least once a
year if you've got a brand-new water heater start flushing it every couple of
months look a hose up to the drain valve at the bottom run it into a five-gallon
bucket every couple of months that will keep the calcium magnesium and
everything else from building up in the bottom of your water heater it'll make
it last longer and it'll also help keep it at a higher efficiency rating on a
tankless water heater and guys this is the big deal you're supposed to flush
that every year with a chemical that cleans out the inside of it that heat
exchanger that I told you about is very narrow if you've got calcium and
magnesium building up on the inside of it it restricts your flow path if you've
got a tankless water heater and you've got a faucet whether it's a kitchen
faucet or say it's a a shower valve you're not getting hot water there but
you're getting water everywhere else chances are your expansion I mean your
yeah your expansion tank in there though the water going through there is not
getting high because it's not moving fast enough to let it know to kick the
burner on it's just barely running and that's either because your your assembly
in there is clogged your aerators are clogged and now you've reduced that flow
restriction where it's not getting through there like it should and it's
not kicking it on the tankless water heater
one of the first troubleshooting things I do on a tankless water heater is go
through and pull aerators out turn the faucets own and see if I get hot water
your tankless water heater gets flushed once a year with chemicals normally you
want a plumber to do that because they've got the pump they've got the
right chemicals they come in they do it shouldn't be a mess easy to do tank top
water heaters flush them at least once a year but if you've got a new one
flush it every couple of months you'll be really glad that your efficiency
rating stays up and your water heater will last longer
my name is Roger Wakefield with Texas Green Plumbing I am the expert plumber
and at Texas Green Plumbing we're saving you money one drop at a time have
a great day