How hard is it to swap out a shower faucet?
September 14, 2021 7:08 PM   Subscribe

We have an outdoor shower and the pressure and temperature increase at the same time. I want them to be separate so I can have less pressure but still hot, or more pressure and cold. My experience with plumbing is very minimal, but I have changed showerheads and replaced rubber washers and the like. Is this something that a novice can do? Could I purchase a new faucet, watch some Youtube videos, and do it?
posted by 10ch to Home & Garden (13 answers total)
Are there regulators on each input that might allow you to adjust the input pressure?
posted by nickggully at 7:25 PM on September 14 [1 favorite]

Yeah, I mean, with youtube and some basic hand tools; a strap wrench might help enough to warrant buying a cheap one. This is like a two or three trips to the hardware store job with an exposed zone like that if you're going to replace the whole thing. This is a fairly easy swap, but might have a couple fiddly parts to it.

I personally would inspect the cartridge first, because it just shouldn't be acting that way? It's easier than replacing everything there. Basically, the water mixing mechanism can be clogged or busted, and it shouldn't be acting that way (unless it's just a terrible, terrible fixture; a decent cartridge is not going to increase the pressure with one water selected over the other unless something is woefully ill designed or busted).

Replacing the cartridge should only be $40? I'd go this route first.
posted by furnace.heart at 8:22 PM on September 14 [6 favorites]

Probably a bigger job than you want to get into. You'll need to cut the shower control away from the existing pipes an put a new one in place. I did it once for the same reason as you; switching from a Moen Positemp to a Moentrol. Then again, being outside and not worrying about flooding your house, it's a good situation to learn some skills and YouTube is full of great hands-on instruction but it looks like you've got some plastic piping, which would likely mean buying specialized crimping tools.
posted by brachiopod at 8:27 PM on September 14 [2 favorites]

Personally I'd go super old school and redesign the entire thing with independent hot and cold taps. Single lever mixing faucets look very slick and all, but they're a pain in the arse to repair and have weirder failure modes to boot.

Having separate taps in the hot and cold water lines also means you can run separate lines from each tap up to a T junction that mixes the hot and cold flows immediately upstream of the shower head, instead of having a single long pipe running up from the mixer. That makes tap adjustment take effect very nearly instantly, because you're never waiting for a bolus of before-adjustment water to make its way from the mixer to the shower head.

And sure, this only makes the shower temperature a second or two faster to respond, but the perceived improvement in controllability is huge. Plus, when your shower gets a case of the drips all you need to do is change a pair of cheap, standard tap washers that are easily and obviously accessible using nice big wrenches, not some fiddly and probably proprietary cartridge that's usually a total pain in the arse to get to because some undersized and awkwardly positioned set screw has corroded a tiny bit and/or had its head chewed out by previous attempts to shift it.
posted by flabdablet at 8:46 PM on September 14 [3 favorites]

It's going to be considerably more involved than just screwing on a new shower head, but this being an exposed outdoor shower makes this a lot less risky than an interior shower. It would be easier to say with a few more photos, but from the one you linked, some (all?) of your plumbing is PEX, with expander fittings. That type of fitting requires special tools to expand the ring at the end of the pipe, then you shove the fitting inside in the few seconds before the plastic ring contracts back to the original diameter and captures the fitting. It's all held together by friction, no glue anywhere. The rings/fittings are designed to be single use, so to change the valve, you'd have to cut the old pipe off and install new pipe/fittings. You may be able to cut off the existing ring and save the pipe, but you'd have to be very careful and a bit lucky. I haven't personally installed PEX, but have seen it done. Looking at the hot supply, because of the existing splice, I'd expect you probably have to replace back to the elbow, if not further. For the cold, you'd probably have to replace past the elbow, splicing into the vertical portion. I can't tell what's going on with the vertical pipe to the showerhead, so not sure what's involved there. (There are other types of fittings, so you may have other options to tie into the existing PEX, but at any rate, you'll need an assortment of fittings and/or tools beyond a wrench.)

All that said, you should consider nickggully's suggestion to verify there isn't a screw or something that's limiting the cold water pressure, and furnace.heart's suggestion to replace the cartridge in the existing valve, as those would precludes any pipe replacement.

First thing I'd check, if you're replacing anything--are there hot and cold shutoffs upstream of the shower that you can use to turn off the shower without turning off water to the whole house? If so, then even if you get in over your head, you just leave the outdoor shower out of commission until you buy the correct parts/hire a pro. If you have to, say, turn off hot water to the whole house, it's going to be more important that you have all the correct tools/parts before you even start, and not drag out the project.

And on preview, if you go flabdablet's route with two valves and a tee, be sure that you have anti-scald protection, either through a specialized tee, at the water heater, or elsewhere in your system. One of the features that the mixer valves provide (at least the new ones) is that if there's a drop in cold water pressure (say a toilet is flushed), the valve automatically reduces the hot water pressure to keep the same relative volume of hot/cold, and therefore the same temperature. Without that protection, less cold means more hot, potentially way too much hot... I think that in some (many/most?) jurisdictions, code now requires anti-scald protection in new installs.
posted by yuwtze at 9:36 PM on September 14 [2 favorites]

Good point. Our house has a tempering valve between the water heater outlet and the rest of the house to make sure that no hot water pipe ever carries water at scalding temperatures.
posted by flabdablet at 10:19 PM on September 14

Best answer: You basically need to replace your single control with separate volume and temperature controls.

The new temperature control (mixer valve) will go where the current control is, and it should be a straightforward swap since it will also have the two hot/cold inputs and one mixed output for the shower.

Then, above the temperature control, between its output and the shower head itself, you'd add the new volume control. This has a single input and single output, and will go inline on your single vertical pipe.

Alternatively, you can get a combined unit which both temperature and volume controls together, don't forget to get the trim with it.

That truly is a drop-in replacement, though you'll still need to do some youtube research to learn how to connect it. But as others say, it's an outdoor shower, so it's the perfect learning opportunity!
posted by jpeacock at 6:13 AM on September 15 [1 favorite]

I don't think you can get what you want. Shower pressure is regulated by the shower head (Federal Regulations), so you really can't change the pressure by changing out those parts inside.

So I disagree with not changing out the shower head to do this. You need to get on ebay or whatever and buy an old showerhead or one where you can remove the pressure restrictor.
posted by The_Vegetables at 8:49 AM on September 15

I think your shower is new enough to have a pressure equalizer built in (ie: the water pressure to the shower doesn't change when you flush the toilet or turn the water differently).
posted by The_Vegetables at 8:50 AM on September 15

Shower heads are rated to 2 to 2.5 GPM, so if you compare your shower head to your faucet via filling a bucket for 1 minute, the faucet will show your max pressure available vs how much pressure your shower head is restricting. You can do this in your inside bathroom if your outdoor shower doesn't have a tub faucet.
posted by The_Vegetables at 8:54 AM on September 15

I personally don't know what I'm doing when it comes to plumbing. I have replaced faucets (and in fact will replace one later today once FedEx gets here) and I managed to replace a sink drain that required cutting out the old P-trap with a hacksaw (that involved at least two more trips to the hardware store than expected), but the combination of tools and parts needed for all the different pipes visible in that photo might still have me calling a plumber to replace that valve.

Worst case scenario: we replaced a cheap mixing tub/shower valve and diverter (in our main bathroom) with a Grohe kit that has a thermostatic coupler and not just a pressure balancer, as well as separate controls for water temperature and water volume. It took a professional plumber and two assistants an entire day, partly because of all the stuff they had to cut out of the way and a brace they needed to install on the back side of the shower wall to support the increased weight of the new shower head assembly. The Grohe kit came with support and bracing requirements that may have been more specific than a bog-standard Delta, Kohler, or Moen drop-in replacement, but the installation instructions were incredibly thorough. If you knew what you were doing, had all the right tools, and didn't have walls in the way while you cut stuff out it could be a complex but doable DIY project.
posted by fedward at 9:30 AM on September 15

Response by poster: A follow-up here to say I should have used the word "volume." This isn't a water pressure issue.

The valve trim (and probably the value itself) couple the volume and temperature, I want them to be able to be set separately.
posted by 10ch at 9:49 AM on September 15

A follow-up here to say I should have used the word "volume." This isn't a water pressure issue.

A plumber can change your single knob to a 2 knob configuration (they are worse in my opinion so not sure I'd do that - but it's your house) but that will not change the amount of water pressure/volume (except if it's less than 2.5 gpm, or your pressure/volume can change between a drip and maximum) because that is the max allowed out of a showerhead. Changing how the knobs mix the water will not increase volume of water beyond.

A tub spout is generally rated for 7 gpm or lower, so it will fill at 30 gallon tub in about 5 minutes. A shower is maxed at 2.5 gpm at 60psi so it will fill the tub in about 12-15 minutes.

You will not get a 7gpm shower head (more pressure) unless you buy an old one or one where you can remove the limiter.

You can change your knob only to get one that is adjustable like a sink where you pull it forward to change the volume and to the left to change the temperature, but that will not change the volume out your showerhead as 60 psi is pretty low.
posted by The_Vegetables at 7:32 AM on September 16

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