Faucet O-Ring Replacement: Most Common Service Item
The American Standard 4433700 faucet uses a spring-loaded lever valve with a rubber seat O-ring. When the faucet drips with the lever in the closed position, the O-ring has deformed from heat and mineral exposure. Order the American Standard O-ring repair kit specific to the 4433700 model from the American Standard Parts Store -- generic O-rings may not match the seat geometry and will not seal correctly. To replace: shut off cold supply, drain the tank via the faucet lever, remove the lever setscrew at the base of the handle, pull the lever and internal spring assembly out of the faucet body, swap the O-ring, reassemble, restore supply, and test. Approximate time: 20-30 minutes.
Tank Assembly Replacement
If the American Standard 4433700 tank does not heat after verifying the GFCI outlet is live and the power cord connection is secure, the heating element has likely failed. American Standard sells the complete tank assembly as a replacement unit -- the element is not available separately. Replacement tank part number is specific to the 4433700.002 vs AS-1064 -- verify your model number before ordering. Replacement procedure mirrors original installation: disconnect supply lines and power, unmount the old tank, mount the replacement, reconnect, and recommission. The new tank ships with a factory-set thermostat; recalibrate to your preferred temperature after the first heat cycle.
Supply Line Inspection and Replacement
The 3/8-inch supply line feeding the 4433700 tank operates in the hot, humid under-sink environment near a 1650W heating element. Inspect annually for corrosion at the ferrule, kinking, or mineral crust at the tank inlet. Replace every 5-7 years proactively. Use only braided stainless lines rated for 125 PSI -- plastic-jacketed lines rated for lower pressures are not appropriate in this application. When replacing the supply line, inspect the cold shutoff valve for slow drips and replace the packing if weeping is detected.
Descaling the Tank in Hard Water Areas
Water hardness above 7 grains per gallon (GPG) causes mineral scale to accumulate inside the stainless tank on the heating element surface. Scale reduces heat transfer efficiency, causing longer heat-up times and increased energy draw. Descale annually: shut off supply, drain the tank completely via the faucet lever, fill with a solution of 1 part white vinegar to 2 parts water, soak 4-6 hours, drain, and flush with fresh water twice. Do not use phosphoric or hydrochloric acid descalers -- they damage the 304 stainless tank interior and void the warranty. Citric acid at 5% solution is an acceptable alternative to vinegar if preferred.