– [Narrator] All right everybody,
welcome to TomahawkDIY. I’ll show you how to
repair a backflow preventer which can be very easy
when the inner components are broken. Starting it up this spring I discovered that there seems
to be some faulty components inside this backflow preventer. This particular model is a Febco 765-1, the one is for one inch, it should be a fairly
straightforward item to repair. There’s a rebuild kit
that you can purchase that goes inside here
for some of the parts that are more than likely
where the damage is. So we’ll take a look and see how it goes. The two valves here are now shut. These relief valves or check
valves, those are shut. Let’s go ahead and open the water and let it flow out and see what happens. (water gurgling) All right, so I’ve got
the valves open here now and you can see there’s water
that’s actually dripping down coming from under the bell here. So something in there, whether it’s an O-ring or
maybe some of the components that move up and down in
the backflow preventer have failed, we’ll find out. But the leaking water’s
obviously a problem. So in order to fix, begin our fix, we’re gonna first shut the valves to the backflow preventer. To isolate the backflow preventer we’ll relieve some pressure to do that. There’s plugs in the
side, those can be removed and taking the screwdriver we can open this up. (water gurgling) Allow a little bit of water
and pressure to drain out. When it comes time to turn these back on we’ll want to remember
to close those valves. So first here on the top there’s a nut, fairly
easy to take off the bell. All right, so we have the bell, this is essentially just
an umbrella or cover to keep debris from falling
inside the backflow preventer. Let’s take a look to see inside here to get an idea of how this works. Looking down there’s a plastic cover that spins freely around this shaft and there’s some rubber
gasketing in there. I’m gonna go ahead and
slowly open the valve, water’s starting to fill up and coming to overflow. Now you’ll see it pop up as we give a little more pressure. (water gurgling) – [Young Boy] That is a lot of water. – [Narrator] All right,
so you see this device has now popped up, it’s sealed against it. I saw this spray initially until there was sufficient pressure to actually cause it to pop and we’re still leaking down the side which suggests maybe
that there’s something either blocking some of
the gasket or damaging it. All right there’s a few
different ways to loosen this. These components, they say
right on them to hand-tighten. But of course, over time, they can get sticky and unfortunately not give way. So at first if the loosening
by hand doesn’t work, another approach is
using some channel locks and getting a good grip on the plastic and just backing it out. And you can see this is giving way for us. Okay, we’ve got this loosened, can go ahead and pull this out, let’s see what we can learn. Ah, it looks like our
problem’s right here. This gasket on this assembly is cracked, right there, which
explains the slight leak that we saw coming through. This entire piece needs to be replaced. Note there’s an O-ring here, the typical rebuild kit
will include a new O-ring. That water in there, that is an indication of why it’s so important to make sure this is fully drained in the winter time if you’re in a freezing area. So the way this assembly works is these two pieces slide together and as it sits in there, water pressure presses
up against the bottom. You notice at first, before
there’s much water pressure, it works it’s way around and water comes spitting out of the top and then as the water pressure builds this slides up and seals on the gasket. Just like that. Of course, with this
crack we’ve identified the water’s making its way past. All right, so to replace the poppet and this inner valve, this backflow valve, you get your new part and this part’s gonna drop inside. Be sure to remove the old O-ring. We’ve got a new O-ring right here and then you put this whole assembly in. It’s important to screw this on but only to screw it on hand-tight. Screwed it down hand-tight. We can now put the bell back on and tighten this down. Before I put that back on I’m going to turn on the water and check to make sure it’s functioning properly. So let’s check the water. We’re going to open this valve slowly and we should see the water fill and we should see the backflow preventer perform its function. We’ll turn on the water and see how this performs. Going to turn it on slowly. And it pushed up the poppet creating the seal. It doesn’t appear to be any
water leaking down the sides, so we should be good to go. Now the last step is to
simply replace the bell. We want to tighten down the nut. (wrench clicking) This doesn’t need to be terribly tight, it’s really just a rain shield to keep things from getting in. And with that we’ve completed replacement of the backflow preventer, of the innards of the backflow preventer and we’re good to go. Thanks for watching TomahawkDIY, don’t forget to subscribe or leave a comment, Like the video if you enjoyed it.