What Is in the Box and Pre-Installation Checklist
Delta includes: bidet seat with mounting plate, T-adapter for 7/8-inch supply connections, bidet supply hose (24 inches), mounting bolts and nuts, and instruction sheet. Before starting, confirm: GFCI 120V outlet within 4 feet, toilet bowl shape matches seat model (elongated 1H604-E, round 1H604-R), and household water shutoff valve is operational. If the shutoff valve under the toilet has not been turned in several years, exercise it by turning it fully closed and fully open twice before relying on it for installation.
Step 1 -- Shut Off Water and Remove Existing Seat
Turn the shutoff valve clockwise to close. Flush the toilet to empty the tank and relieve pressure in the supply line. Place a small towel or bucket under the supply line at the tank base -- residual water will drip when the line is disconnected. Remove the existing toilet seat: lift the hinge caps, hold the bolt from above with a flathead screwdriver, and unscrew the nut from below with pliers or an adjustable wrench. Lift the seat off. Clean the bolt hole area of any mineral deposits or old rubber gasket material.
Step 2 -- Install the T-Adapter and Bidet Supply Hose
Unscrew the existing supply hose from the toilet tank fill valve connection point. Thread the Delta T-adapter onto the fill valve shank -- the adapter is brass with rubber gaskets on each port. Hand-tighten, then snug with a wrench (do not exceed one half turn past hand-tight on the brass-to-porcelain connection at the tank). Reconnect the existing supply hose to the lower port of the T-adapter. Attach the Delta bidet supply hose to the side port of the T-adapter and route the hose to the bidet seat inlet port. The inlet port on the Advance Clean seat is on the left rear of the seat housing. Hand-tighten the coupling nut at the seat inlet.
Step 3 -- Mount the Seat and Run the Leak Check
Place the Delta mounting plate over the bolt holes with the plate flange facing the rear of the toilet. Insert mounting bolts through the plate and bowl holes, thread the included plastic nuts from below, and tighten progressively: hand-tight, then snug with a wrench. Slide the Delta bidet seat onto the mounting plate from the rear -- push rearward and down until the seat locking mechanism clicks. Tug the seat forward to confirm it is locked. Open the shutoff valve slowly. Inspect the T-adapter connections, the supply hose ends, and the seat inlet coupling for drips. Dry each connection point with a cloth, wait 60 seconds, and recheck. A dry recheck confirms a successful installation.
Step 4 -- Power Connection and First Use
Plug the Advance Clean power cord into the GFCI outlet. The seat indicator light will illuminate after a short startup sequence. Sit on the seat to activate the occupancy sensor -- the seat must detect weight before wash functions activate (this is a safety interlock). Test posterior wash at the lowest pressure setting and confirm water reaches the target area. Increase pressure to verify adjustment function. On the 1H604, test the dryer function and deodorizer. Run a manual nozzle self-clean cycle via the dedicated button on the side panel. The first use cycle is complete when all functions respond correctly and no drips are visible at any water connection.