Tools and Materials
Required: 1.375-inch hole saw, basin wrench, adjustable wrench, Teflon tape, silicone sealant, GFCI tester. The Moen instant hot kit includes the tank assembly, faucet body, and mounting hardware. You supply a 3/8-inch braided stainless supply line (minimum 24-inch length) and a 120V 3-prong power cord rated for 15A. Do not use plastic-jacketed supply lines in the high-humidity under-sink environment near a 1500W heating element.
Step 1: Drill the Sink Deck Hole
Shut off the cold water supply valve under the sink. Mark the faucet position on the sink deck -- typically the right-side pre-drilled hole or a new position 4-6 inches right of the main faucet. Drill a 1.375-inch hole using a step drill or hole saw. On stainless steel sinks, use cutting oil and slow speed to prevent overheating the blade and work-hardening the steel. Deburr the hole and apply a bead of silicone around the faucet shank landing area before insertion.
Step 2: Mount the Faucet
Feed the faucet supply tube and shank through the drilled hole from above. Below the sink, slide the rubber gasket and then the brass mounting nut onto the shank. Thread the nut clockwise and tighten with a basin wrench to 15-20 inch-pounds -- snug but not so tight that the faucet body rotates on the sink deck. Confirm the faucet nozzle is positioned over the sink bowl center.
Step 3: Connect the Tank
The Moen hot water tank inlet is a 3/8-inch compression fitting. Apply Teflon tape to the male threads and connect the cold supply line from the shutoff valve to the tank inlet. Connect the faucet outlet tube to the tank outlet fitting. Moen tanks ship with the thermostat pre-set to 190F -- do not adjust until first heat cycle is complete. Mount the tank to the cabinet wall or floor using the included bracket and screws, positioning it within reach of the electrical outlet.
Step 4: Power Connection
Plug the tank power cord into a GFCI outlet. If no outlet exists under the sink, have an electrician install one on a dedicated 15A circuit before proceeding -- do not use a power strip or extension cord for a 1500W heating appliance. The Moen tank draws 12.5A at full wattage during the heating cycle, leaving 2.5A headroom on a 15A circuit.
Step 5: First Fill and Temperature Setting
Open the cold water supply valve and allow the tank to fill completely. Hold the dispenser faucet lever open until water flows steadily without sputtering -- air purge is complete at this point. Close the lever. Plug in the power cord. The heating indicator light glows during warm-up, which takes 15-20 minutes from cold. After the first full heat cycle, test output temperature with a digital thermometer -- factory setting delivers 190F at the faucet. Increase the thermostat dial clockwise to raise temperature toward 200F for hotter output.