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#7 Why is this backflow preventer dripping?
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The backflow preventer is a misunderstood piece of hardware in hydronic systems. "My backflow preventer has failed. It's dripping. What should I do?" It's easy to replace it.... but, has it really failed?
Likely the backflow preventer is doing it's job! The culprit? Debris stuck in the check valve. Greg and Dan discuss how and why the backflow preventer can drip and what to do to eliminate the nuisance drip.
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http://bit.ly/AskCaleffi-NuisanceDripInBFP
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[Music]
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welcome to
00:06
ask Caleffi the podcast that dives into
00:08
real life problems that plumbing and
00:10
hvac technicians face in the field
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we're your hosts from the Caleffi tech
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support team i'm greg tubbs
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and i'm dan firkus welcome we look
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forward to sharing some stories from our
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tech calls and using our background and
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expertise to make your days a little
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easier
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there welcome back we're on episode
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seven of the ask Caleffi podcast
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what are we talking about today dan oh
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geez greg the
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probably one of our most common
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questions why is your backflow preventer
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dripping
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that is probably one of our most common
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questions why we get that question
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all the time yeah and you know it's
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funny
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this is kind of a misunderstood piece of
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hardware that's in a hydronic system
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yeah
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you know the the other way we get that
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question is my back full
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preventer has failed it's starting to
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drip yeah and then
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it's easier for a guy to go and replace
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it right
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it's less time consuming but has it
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really failed
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no no it's not the simple answer is it's
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just dirty it's doing its job
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right it's doing its job of interrupting
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flow
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when there's debris stuck in the check
01:23
right yeah well the debris in the check
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is what causes it to continue to weep
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but the fact that you know anytime
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there's a change in pressure in the
01:31
system or
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water hammer or surge you need to
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protect
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the domestic side of your of your
01:38
plumbing system
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right and that's what this backflow
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preventer is there to do right it's
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keeping
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the boiler side water from flowing back
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into the domestic water right yep
01:49
protecting your domestic source
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so simple answer is that you know when
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it continues to drip
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has it failed no no it really hasn't
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really hasn't failed no
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it really hasn't that sealing surface is
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so tiny
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where those double checks hit that piece
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of brass
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that it doesn't take much more than a
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grid of sand and i know that sounds kind
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of silly
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but that's how these are designed it
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doesn't matter i mean you and i have
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been in the field long enough we've seen
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other competitors honeywell
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a watts whatever we've seen them
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go to them and they're leaking you know
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and what's what's the easiest thing to
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do
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just yeah just replace this replace it i
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mean that's quick and simple and
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but you know you have to realize that
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you know there's cost there and and my
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biggest thing is you know a lot of guys
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want to come back and warranty the
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product because it's
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it's dripping and it's like okay that's
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a kind of a gray line because it's not
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really a failure it's
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it's doing what it's designed to do
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it's just the fact that you have a
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little debris stuck in it and the debris
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can come from either side of your system
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right most of the time it comes from the
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feed water side right
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i mean we've seen i've taken some of
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these apart and even found pieces of
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thread tape stuck in it
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chunks of solder copper shavings
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yeah copper shavings or in worst case
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scenario it's
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you know it's hard water chunks you know
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pieces of lime and scale
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that have somehow made it made their way
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through or flaked off the body
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and and gotten stuck in there right well
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because in reality
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these checks aren't opening and closing
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all the time
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they're opening when they add water to
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the system and then closing
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and if you get a water hammer or a surge
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you know that's when it can knock some
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debris loose
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and that debris will get stuck in those
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checks and it and it won't
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reseal right that those checks will
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actually float a little bit
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and when they float that allows a little
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inrush of water
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usually on the on the high pressure side
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to come in
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and when they go to settle back that's
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when that piece of debris gets wedged in
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there
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right yeah i mean common guys probably
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seen that with relief valves over time
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you'll get a relief valve that'll
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you know with a little thermal expansion
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might open up and get a piece of debris
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and continues to drip it's the same
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concept with our check valves you get
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that chunk in there
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i mean you and i both have tried to
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explain
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how to take one of these apart and clean
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it
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obviously the quickest solution to the
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problem is just replace one and move on
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but if you didn't have one on the truck
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at worst you're gonna need is a set of
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ceiling washers right right
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yeah absolutely you know you're right
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the you know the quickest solution is to
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replace
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it if you have one but when you're on
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that job site and you don't have one
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convenient
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then it's not your quickest solution
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because you have to go get one and come
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back with it it's a second trip it's an
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inconvenience to a customer or homeowner
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so at that point your quickest solution
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may be to take it apart and clean it out
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right so we actually got one here in
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hand
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and it's usually the to get it apart
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you start with breaking the union nuts
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right you clean off the tail pieces
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you remove any what's left of any debris
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or any any pieces of that
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that sealing washer that is in in the
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unions themselves right
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then you can pull the body out and
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there's this big
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inlet side where the inlet check sits
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inlet check is usually where we find
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most of the debris build up
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right and getting this thing apart it's
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not exactly
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the prettiest job is it i mean it's not
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not easy i mean it takes
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you could take a channel locks and a
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pipe wrench yeah
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but it's sealed with a ceiling washer so
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it's not like
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it's it's not necessarily that it's
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overly tight
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that you need some aggressive tools to
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to get it open it's that
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you know it's a large flat surface it's
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kind of a little bit
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challenging at times to grab but it
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seals with a ceiling
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or with an o-ring actually seals with an
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o-ring
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so you don't have to overly tighten it
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when you put it back together either
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no so and once you get this inlet
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tailpiece off it's the p the larger
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piece with the two ears on it
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you spin that loose you pull it out
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and that's your first check valve that's
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your first check valve right there
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you're actually able to get to the inlet
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side check
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now you look at and go okay how do i
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clean this thing well really
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all you need is probably just a punch or
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even a screwdriver just to move that
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little check valve in there
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you can see the dome down inside and
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what i would tell a guy to do is take it
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take a screwdriver and just depress that
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dome push down in it
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and flush some clean water through right
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you go right over to the slop sink
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launcher
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or a sink and flush through it yeah i
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mean it's that simple
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and then you could also spin it around
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and
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flush water through the the spring side
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you know just depress it again from
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underneath
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push that dome up in there and reverse
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direction yep sure
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and then you can get all the debris out
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of it and then
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what's nice you don't have to worry
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about any seals on the body per se
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just until you hit the hit the union
06:59
side of things right
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you can actually get in there once you
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have it apart and you can push
07:04
the outgoing check the outlet check you
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can actually push
07:08
that out of the body as well and you i
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mean with my finger here i have it my
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hand with my finger you can actually
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push the check valve
07:16
open and almost with my finger wipe the
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seat
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yeah but take that over to a sink and
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push it open and flush that out and you
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can flush that in both directions clean
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it out
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and then just put it back together
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there's a spring in the middle
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that allows with you know the double
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check action
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right but very simple to put back
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together too
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and actually looking at this that is
07:38
right right there
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is where you're gonna find the source of
07:41
the leak so you could almost take care
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of
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the source of the leak the debris stuck
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in the
07:48
on the back side of that first check
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because that
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is where it meets up to the downstream
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second side check
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right and you don't necessarily
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have to pull that body apart in order to
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clean that part all you need to do is
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grab hold of it with a pair of needle
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nose or even stick a screwdriver into it
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just pull it out yup yo and then the key
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is as you thread it back together
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it's sealing with that o-ring so you
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don't have to overly tighten it
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just enough to get that to bite down and
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seal and then
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put in a new set of sealing washers and
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put it back in place
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right and you know this description is
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almost easier
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easier showing on a video i mean you
08:27
guys are listening to us going okay
08:29
well what's that look like i think what
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we're gonna do is maybe shoot a little
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youtube video
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yeah and then uh try to put a link in
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the description
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of the show notes here yeah it'd be
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great to get a video out and
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show how easy it is to take it apart and
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clean it out
08:43
yeah i think that would be phenomenal so
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and you got to remember that the
08:48
the double check back flows that we're
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talking about
08:52
um are used for domestic systems they're
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not for potable water they are
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for you know they are low lead because
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they are coming in contact with domestic
09:01
water but they're designed
09:03
specifically for hydro hydronic
09:06
heating hydronic fill side
09:09
exactly well now that we've kind of just
09:13
went through all that with how to clean
09:14
it and you know one of the reasons why
09:16
it drips is dirt in it
09:18
the other one is the water hammer you
09:20
know if you have
09:22
a plumbing system that doesn't have
09:23
hammer arresters on it
09:25
i think the biggest offenders are
09:27
usually wash machines
09:28
and dishwashers yeah those have really
09:31
quick reacting valves and they're
09:33
usually
09:33
a pretty high flow behind them so when
09:36
they slam
09:36
shut um they tend to create a water
09:39
hammer in the system and that can cause
09:40
those checks to bounce you know you'll
09:42
if you're down there and you know it can
09:44
cause your pipes to maybe rattle a
09:46
little
09:46
or right or the check valves in
09:50
in the backflow preventer to bounce and
09:52
weep and
09:54
yeah and a lot of times that'll be just
09:56
a quick a quick weep and it might not
09:57
even be
09:58
fast enough for debris to carry in there
10:00
right not always sometimes it does that
10:02
one thing will lead to another but most
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of the time
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it'll be a quick weep and the homeowner
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will walk by because hey
10:09
maybe the mechanical room's right by the
10:12
laundry room
10:13
or in it right and they see you know
10:16
water on the floor
10:17
where'd that come from and then you know
10:19
the technician gets called out to the
10:21
job
10:22
and they're looking around going i don't
10:24
it's not doing it now
10:25
sealed and dried up because it did its
10:27
job but
10:28
you know but then over time i mean that
10:30
may happen
10:32
over and over and over again because
10:34
it's not going to happen once with a
10:35
wash machine or
10:37
or dishwasher so it happens over and
10:39
over and over and then at some point is
10:41
when that little grain of debris is
10:43
gets in the check and right yeah then
10:45
you're done then you're getting a
10:47
service call
10:47
yeah but the good news is that we do
10:49
offer
10:51
a replacement body that comes with
10:52
ceiling washers under our 573-100a part
10:56
number
10:57
so that's something that you can throw
10:58
on your truck
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or you can just order whatever your
11:02
supply house has
11:03
for 573 backflow preventers they're all
11:06
the same the body is the same what
11:08
changes is the tailpiece is the
11:09
connection type
11:10
right so i mean if you had to in a pinch
11:13
if you just had a half inch sweat model
11:15
which i think is probably the cheapest
11:16
one with the ceiling washers in it you
11:18
could just
11:18
remove the the union nut and tail piece
11:21
and you got at least the body and set of
11:23
ceiling washers to get that
11:24
that customer back into service right
11:27
exactly and
11:28
our three quarter and half inch model
11:30
because face it you'll get on a job site
11:32
where
11:32
at one point we used to have a tag
11:34
riveted on it that said 573 half inch
11:37
and three quarter and i get a lot of
11:39
calls from guys about that they're like
11:41
well
11:42
i need the three quarter inch one
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because it's three quarter inch pipe
11:44
connected to it
11:45
the body is the same whether it's half
11:47
inch or three quarter the body's the
11:49
same it's the connection point that
11:51
changes so
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don't be afraid if you are out servicing
11:55
a system with a three-quarter inch
11:56
connection and
11:57
three-quarter inch you think you have
11:59
the three-quarter inch body and you have
12:01
a half-inch on your truck
12:02
that works yeah interchangeable they're
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same body bodies are the same
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all universal well yeah i think we
12:08
covered that really well
12:10
um i guess uh any closing thoughts on
12:13
backflow preventers
12:15
no i think we did a great job of
12:16
covering that i mean
12:18
if you guys have questions please don't
12:19
be afraid to call us you know we're
12:21
always here to help i think
12:22
greg had a good point with making a
12:24
short video showing how to disassemble
12:26
it and clean it so i i would keep your
12:27
eyes out for that that will come too
12:29
yeah well that's the end of it for this
12:31
week uh
12:32
tune in next week we're going to talk
12:34
about pressure reducing valves yeah
12:36
great topic we get a lot of calls on
12:38
pressure reducing valves and it's good
12:40
to jump back on a plumbing topic
12:41
absolutely see you next week thank you
12:44
for tuning in
12:46
if you ever need help please feel free
12:48
to contact our tech support team
12:49
anytime at techsupport.us
12:53
caleffi.com or call us during our
12:56
business hours
12:57
at 7 30 a.m to 4 30 p.m
13:01
central time at 414
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