Do I need to upsize my supply lines for the fast-fill faucet?

No, your existing 1/2 inch house supply lines will work with an Ella fast-fill faucet. Every Ella 2-piece and 5-piece fast-fill set includes two 3/4 inch by 5 foot braided stainless steel supply lines, and the faucet is piped for 3/4 inch, so those lines connect to your house shut-off valves whether the house side is 1/2 inch or 3/4 inch. Ella recommends 3/4 inch house lines because they fill the tub faster, which makes the larger size a recommendation rather than a requirement, as What Are the Supply Lines and Shut-Off Valves on a Walk-In Tub? explains. This page covers what upsizing actually changes, what it cannot fix, and where to put the shut-off valves so you can reach them after the tub is in.

What Ships with the Faucet and What Your Plumber Supplies

The question usually comes from mixing up two different sets of pipe: the braided lines that come in the faucet box, and the house piping behind the wall. The table separates them using only the figures Ella publishes.

What the differences mean is simple. The faucet side is already 3/4 inch all the way through, so nothing on the tub needs to change for a 1/2 inch house. The only thing a 1/2 inch house line costs you is fill speed, and the only thing 3/4 inch house lines buy you is a faster fill. What Is a Fast-Fill Faucet on a Walk-In Tub? notes that the GPM figures assume 60 PSI and ideal plumbing, and that real fill times run 7 to 15 minutes depending on tub size and your water supply.

What Bigger Lines Can and Cannot Fix

Larger house lines remove one restriction, but the fill rate you actually see is set by the whole house side. Ella's published guidance lists four things that change the real-world rate: house water pressure, pipe size, the distance from the water heater to the tub, and hot water being used elsewhere at the same time. Upsizing to 3/4 inch helps with the second item only. It cannot make up for low pressure, a long run from the heater, or a shower running in another bathroom.

Hot water capacity matters as much as pipe size. The second video on this page is Ella's guide to hot water supply, and it recommends the maximum capacity water heater available for your house, states that anything less than 75 gallons is not recommended, and says a dedicated hot water system just for the tub is worth considering on the largest tubs such as the Big4Two and the ShaK. It also repeats the 3/4 inch supply line recommendation with easily accessible shut-off valves, and reminds you that 5 foot supply lines are included with every Ella 2-piece or 5-piece fast-fill set. For a tankless heater, the published figure is a rating of 11 GPM or more. How long does it take to fill a walk-in tub? puts these pieces together with the gallon figures for each model.

If you already have the faucet installed and the fill is slow, upsizing is not the first move. Why Does My Walk-In Tub Fill So Slowly? starts with the two shut-off valves behind the access panel, because a valve that is only partly open is the most common and easiest fix. Then compare the tub with another fixture: if pressure is low everywhere, the fix is on the house side, and if it is low only at the tub, look at the tub's supply run and valves. On a thermostatic faucet, scale on the valve's intake screens can choke flow to a trickle even when the water is hot, and your plumber cleans them with a soft brush and a lime scale remover.

Where the Shut-Off Valves Go

Shut-off valves, also called stop valves, are not in the faucet box. Your plumber supplies them, and placement matters more than most people expect, because the only reason to shut them is a future faucet or hose service. Ella recommends placing them close to the tub where they can be reached through the front apron access panels or a wall access panel, so that service on the faucet does not mean shutting down water to the whole house.

• Plan the valve location before the tub is set, while your plumber can still see the wall and floor.
• Keep both valves within reach of an access panel, with the braided lines routed so they are not kinked.
• During warranty activation your installer leak-checks the supply lines with the diverters on. Ask to see the connections and the valves while the panel is open, so you know where they are before you need them.
• Make sure both valves are fully open when the job is done, since a half-open valve shows up later as a slow fill.

Connecting the Lines Without Leaks

The first video on this page shows the 2-piece fast-fill set being installed, including the supply lines. The hot line carries red markings and the cold line carries blue, both lines on the 2-piece set have reverse threads, and each connection is hand tightened and then given one quarter to one half extra turn with a wrench after checking that the gasket is seated. The same hand-tight then gently snugged rule applies at the shut-off end. Over-torquing damages the internal gasket in the fitting and causes the very leak you were trying to prevent. If a braided line later drips at the loop, the line should be replaced rather than tightened further, and replacement lines are arranged through your Ella dealer or the team at (800) 480-6850.

If You Are Replacing an Older Faucet

Supply line size also comes up when an older faucet is being swapped for the current set. Replacing Your Walk-In Tub Faucet Set, Valves or Hand Mixer explains that the 5-Piece Fast Fill set uses 3/4 inch supply lines while older faucets usually have 1/2 inch lines. If the check valves under your tub have 1/2 inch connections, your plumber fits a 3/4 inch to 1/2 inch NPT adapter, which is a standard plumbing part. You can also keep the existing spout and hand sprayer and change only the handles and valves, adapting the spout supply line from 1/2 inch to 3/4 inch NPT. For a ticket at ellasbubbles.com/support, have your model and serial number, whether your faucet is the 2-piece or 5-piece set, your house supply line size, and a photo of the lines and shut-offs behind the access panel.

Watch: Ella's Bubbles: Determining Correct Hot Water Supply For A Walk-In Tub with chapters and a full transcript.

Related Guides

• What Is a Thermostatic Control Valve (TCV) on a Walk-In Tub?
• Temperature Control Valve (TCV) Stuck or Not Mixing: Cleaning the Cartridge and Replacing the Valve
• Replacing a Failed Thermostatic Control Valve: Cleaning First, Cartridge Versus Whole Valve, and How to Order

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