Ron Hazelton

Is Your Shower a Scalding Hazard? Here’s How to Fix It

Safety

Bathroom

Plumbing Techniques

HOUSE DOCTOR Transcript

HD015 “PRESSURE BALANCING SHOWER VALVE” from episode 615

RON:

If you've ever taken a shower and had it unexpectedly turn freezing cold or worse yet boiling hot? Well, I've got a solution for you.

Has this ever happened to you? You're taking a shower upstairs and somebody turns on the water downstairs and…

MAN:

Oh! Oh! Oh! Oh!

RON:

A solution to this problem is a pressure balancing shower valve like this one, and today we're going to replace this conventional valve with this new one. The way a pressure balancing valve works is that inside is a pressure balancing piston. If the cold water pressure drops, the piston moves to the right, decreasing the amount of hot water. If the hot water pressure drops, the piston moves instantly to the left, reducing the amount of cold water. In either event, it brings the water pressures back into alignment. And that's what keeps you from getting frozen or scalded.

Now when you're replacing a valve like this, you've got to create an opening that's a good bit larger than the existing valve in order to get this out and get the new one in.

Well today, I don't want to disturb this tile right here, so I'm going to make that opening on the other side of this wall.

Now this is the back side of that shower wall, and this mark right here is the center of the valve. Now what I've done is taken a stud finder and I've located the studs on either side of this bay. There's one right there. I did the same thing over there and drew this outline. Now this is a little bit larger than I probably need it, but I want plenty of working room in here, and I also want you to be able to see really well. So let's take our sheetrock saw, just push this through the sheetrock here, and begin to cut out this opening.

There's some cross bracing right here, which you'll see in a second. I had to sort of cut through the last bit of this with a knife. Let's take this off now. Okay, now here's our old

valve right here, and we're about ready to start work, but let's go downstairs now and shut off the water pressure to the house.

With the water turned off, let's go ahead and remove this old fixture from this side. There's a cover plate right there that pries off with a utility knife, and there's a set screw up here. Unscrew this. This will allow us to remove the handle. Okay, there we go, and then there are two screws right here that hold this trim plate in place. Let's back those off.

All right, there's the last screw. Let's pull this piece off. This is kind of stuck on, probably with some silicon sealant. I'm just going to get behind here and pry this a little bit. Quite a bit of sealant back there. It's actually a good idea. It keeps water from running down behind this plate. There we go.

Now this pipe right here is nailed with a pipe clamp to the backside of this 2x4 right here, so I'm kind of just prying the nails loose. There we go. They're almost all the way out now. Now I'm going to take a reciprocating saw. I'm going to cut this block the rest of the way loose here.

All right, now I'm going to cut off…this is the pipe right here, the riser that goes up to the shower…I'm going to cut that off just about right here.

Well, obviously we're back at the bathroom now. I'm going to have to remove this faucet and just put a rod up in there. That'll get it started.

Still pretty stiff. Let's put a, let's put a wrench on here. See if we can get this off.

I'm not going to be reusing this. Otherwise, I'd probably put some tape or something on here to prevent scratching. We're going to be putting a new spigot on. There we go. Just come right off. Good.

Well, that spout is loose right there. So now we're going to cut off these two supply lines. This one on this side first.

Oops, let's see. Let's slow this thing down just a little bit here. All right, and then this one.

There we go, and there is our old assembly.

Okay, now in order to install this new valve, I've had to cut away the sheetrock. Actually, what we've got here is we've got about a half-inch sheetrock, a waterproof sheetrock, about a half an inch of mortar, and then right here is the tile.

Well, it's time to start putting a new pipe in, and we're going to be using half-inch copper, which of course is what was here. We're going to cut this using a pipe cutter. Now this has a, let me show you right here. Now, if you notice, there's a cutting wheel right here, a very sharp cutting wheel, and a roller right here. The way this works is you sort of tighten this up sort of snugly, move it around the pipe, then each turn or so, you tighten this knob right here. That forces that cutter wheel a little bit more in contact with the pipe until after three or four turns, you've cut completely through.

And the next thing we do is take this reamer, which is usually built into a good pipe cutter, and put it on the inside of the pipe and twist it back and forth. Now, the reason you do this is that when you use a pipe cutter, it sort of creates a little curl on the inside of the pipe here. If you don't take that out, it can cause the water to get turbulent and actually create noise inside the pipe.

All right, now once we've got this cut to length, the next thing we want to do is prepare the joints for soldering. This is a wire brush right here. I'm going to stick that right over the end of the pipe. It's got hundreds of little bristles in there. What we're doing is we're taking off the oxidation, dirt, and any oil on the outside of the pipe, leaving this nice, fresh, clean material there. Or, if you don't want to use a brush, you can use this.

This is called plumber's sandpaper or plumber's tape. And just tear off a piece and do the same thing.

Now, really, when you're working with copper plumbing like this, it's a matter of connecting together a bunch of lengths of pipe and various types of fittings. So, you also have to prepare the inside of the fitting in the same way that you prepare the outside of the pipe. And to do that, you want a fitting brush. It just goes right up inside. You twist it around a few times until you've cleaned the inside of this one the same way we clean the outside of the pipe.

Next, you want to apply some soldering flux. Now, this is a chemical that promotes the bond of the solder to the pipe. And we'll put it on the outside of the pipe and on the inside of the fitting that we cleaned. Then we're going to slip these two together. Now, what I'm going to be doing here is assembling several pieces of pipe and fittings, pretty much all of this. And then, once everything is in place, we'll start the soldering.

Well, I've assembled all the pipe and fittings for our water supply lines here, the hot and cold lines. Remember, all of these joints have been cleaned and fluxed. It's all put together. Over here on this side, we've got kind of a typical situation when you're installing a new valve with some old plumbing. That is, that the distance between the supply lines here is different than the distance between the valve inlets up here. So, we've had to offset this line about two and a half inches to the right. And the way you do that is take two 45-degree Ls, one here and one here, with a short length of tubing in between, and that brings it over and lines it up with this port right here.

Okay, we're all ready to start soldering now. Here's my torch. I'm going to turn this on. Get our sparker out here and light this up.

Okay, I've also put a heat-proof mat back here to keep from charring the back of the wall board. And you notice I've unrolled about, oh, 10 inches of solder and made a bend at the end there. I'll show you why in just a second. That allows me to get the solder in precisely where I want it. I'm going to apply heat to this joint just long enough to heat it up hot enough so that it will melt the solder. I don't want to burn the flux out of there.

Usually about 15 to 20 seconds is enough. See that green flame? That's a good indicator. Now, we'll put the solder right here in the joint. You see it melt the solder? It's flowing right down into the joint. Then we'll come up underneath this way. We'll apply some more solder up here. And capillary action will pull this solder up into that joint, even though it's going uphill.

Here's another place where I had to use that offset technique. Actually, this inlet for this port right here for the shower was sitting inside the wall. So by using a combination of 45s here, I came out. 45s here, I came back and lined up with our existing shower riser right there. Okay, everything is in now and soldered up except for our tub spout.

And what I want to do right now is secure these pipes to this wood that I put in here. This is a copper pipe clamp, and I'm using copper nails. One rule in plumbing is you never want to mix metals. You never want to mix steel and copper together because a process happens that causes corrosion of those metals. So we want to use the copper nails with the clamp.

Now, there's that tub spout assembly. So we're going to just slip this right in here. Connect it up to what we already have in place. Okay. Now I'm going to have to put something under here to kind of hold that up. See if that works. All right. And we'll turn up our torch. And go ahead and solder these joints.

Okay, now let's see. Tub's running. Just want to check here and make sure that we have no leaks to any of these joints. This is really important because if we had a problem, I want to see it now before we cover this wall up.

These are small cleats here that I'm attaching to the inside of these studs. I want to give myself a surface to which we can attach this piece of sheetrock that we took out earlier. Let me run these screws in here. There's one. Okay, and then one down here. Now, if you'll notice, I've got one of these on the top up here, one on the bottom down here, and one on this side over here so that every place there's a joint, it's supported from behind.

And since we cut this out very carefully, it should fit right back into position. Okay, just like that. And I'll take some more screws, and I'll run these into that wood strip that we just put up.

Well, with our joints all soldered and everything secured down, we can come back in the bathroom now and start trimming out this faucet. Now, there are a series of fittings that go on here, starting with this sleeve, which slips right on like that. Next, the trim plate slips into position just like this. And there are two holes here and two screws. These go right into the valve housing. Just line it up.

There's a little stop right here that has to be installed. This limits, actually, how far you can open the hot water. So you can set this, if you've got small children, so that it'll only go to a certain distance, and the water will only get so hot. It's adjustable just by taking this Allen wrench, loosening this knurled nut right here, and sliding this up or down. Okay, good. All right.

Now, next, this piece slips on like so. And then this ring goes on top of that. Actually, I think it goes this way, like so. And next, this piece slips on top… Actually, right now, we've got to put a screw in here. This holds all this entire assembly together. Then you want a screwdriver. Okay. And on top of that goes this ring, and then this cover, which is threaded and screws on.

About the last thing we have to do here is to put this tub spout on. Now, this is a clamp-on or slip-on spout. Actually, there's a set screw right here. And as you tighten and loosen this, it clamps this onto the pipe stub coming out of the wall here. But before we slip that into position, let's take some silicone and run a bead of it right around here. This is just in case any water gets behind this or between this and the tile. It'll keep it from running down inside the tile. I'll put a little bit more on here than I need. Then we'll come back and clean off the excess. There we go. Okay.

Now, we just slip this over the pipe stub like that, press it in contact with the tile. Make sure it's straight. And I'll get under here, tighten up that set screw, and then clean off the excess silicone.

Well, we're finished. So let's turn this on. I'm going to set it to sort of comfortably warm here. I'm going to reach over here. And I know for a fact in this bathroom, when this toilet was flushed before, you'd get a surge of hot water here. Flushing the good toilet…

No change in temperature here whatsoever.

Now, this unit, which happens to be made by Moen, retails for about $175. And as you can see, it is absolutely possible to put it in yourself. And it's probably a good idea, especially if you've got children, because it'll protect both you and the kids from possible scalds.

How to Install a Pressure Balancing Shower Valve Yourself

Have you ever been in a perfectly warm shower, someone flushes the toilet or runs the kitchen tap downstairs, and suddenly you're either freezing or burning? It's annoying at best and dangerous at worst — especially for young children.

A pressure balancing shower valve solves the fluctuations in temperature. In House Doctor, Ron

walks you through replacing a conventional shower valve with a pressure balancing model. The job requires some comfort with basic plumbing and soldering.

How a pressure balancing valve works

Inside the valve is a pressure balancing piston. If cold water pressure suddenly drops — say, because someone flushes a toilet — the piston shifts to reduce hot water flow, keeping the mix balanced. The reverse happens if hot water pressure drops. With this, your shower temperature stays consistent no matter what else is happening in the house.

What you'll need

Pressure balancing shower valve
Stud finder
Drywall/sheetrock saw
Reciprocating saw
Pipe cutter with built-in reamer
Half-inch copper pipe and fittings (including 45-degree elbows)
Wire brush and/or plumber's sandpaper
Fitting brush
Soldering flux and solder
Propane torch and sparker
Heat-proof mat
Copper pipe clamps and copper nails
Silicone sealant
Utility knife, Allen wrench, screwdriver, wrench
Drywall screws and small wood cleats for patching

See step by step instructions below.

Ready to take on more projects around the house? At HouseCallsDIY.com, you'll find trusted guides covering everything from any room in the house and outdoors — all written for homeowners who'd rather do it right the first time.

Step 1

Create an access opening

To remove and replace the valve, you'll need a generously sized opening in the wall. Rather than disturbing existing tile on the shower side, work from the other side of the wall — a closet, hallway, or adjacent room. Use a stud finder to locate the studs on either side of the valve bay, then mark out your cut area. Err on the larger side so you have plenty of room to work and see clearly. Use a drywall saw to cut the opening, using a knife for any cross-bracing you encounter.

Step 2

Shut off the water

Before touching anything else, go to your main shutoff and turn off the water supply to the entire house. Don't skip this.

Step 3

Remove the old valve and fixtures

On the shower side, pry off the cover plate with a utility knife. Unscrew the set screw to remove the handle, then back out the two screws holding the trim plate. The plate may be stuck with silicone sealant — pry it gently from behind. (That sealant is actually a good thing; it prevents water from running behind the plate.)

From the access opening side, pry the pipe clamp nails loose and use a reciprocating saw to cut the pipe block free. Cut the riser pipe heading up to the shower. Back on the shower side, unscrew and remove the tub spout, then cut off both supply lines. The old assembly is now free.

Step 4

Cut and prep the new copper pipe

You'll be working with half-inch copper pipe — the same size as the original. Use a pipe cutter until the pipe is cut through. This typically takes three or four turns.

Once cut, use the built-in reamer on the pipe cutter to smooth the inside edge of the pipe. Cutting creates a small curl on the interior that, if left in place, causes turbulence and noise in the water line. Next, prepare every joint for soldering. Clean the outside of each pipe end with a wire brush or plumber's sandpaper to remove oxidation and oil. Clean the inside of each fitting with a fitting brush. Apply soldering flux to both the pipe exterior and fitting interior before joining them. Assemble all pipe sections and fittings before you begin soldering. If your supply line inlets don't align with the valve ports (a common scenario with old plumbing), offset them using a pair of 45-degree elbow fittings with a short length of pipe between them.

Step 5

Solder the joints

Place a heat-proof mat behind the pipes to protect the wall. Pre-bend about 10 inches of solder so you can direct it precisely. Light your torch and heat each joint for about 15–20 seconds — watch for a greenish flame as an indicator that the joint is hot enough

An important note on materials: use copper pipe clamps with copper nails only. Never mix copper with steel — the combination causes corrosion over time.

Once all joints are soldered, solder on the tub spout assembly as well.

Step 6

Test for leaks before closing the wall

Turn the water back on and run the tub. Inspect every joint carefully for leaks. This step is critical — find any problem now, before you close up the wall. If everything looks good, you're ready to proceed.

Step 7

Close up the wall

Attach small wood cleats to the inside edges of the studs to give yourself a nailing surface for the drywall patch. Secure cleats at the top, bottom, and side of the opening so every edge of the cutout piece is supported. Fit the original drywall piece back into position and screw it in place.