Franke faucets are covered by a 5-year limited warrantee and offer years of trouble-free service; however, after extensive use, hard water deposits may abrade the rubber seals and cause the faucet to leak. Consequently, if the faucet develops a leak, the seals have worn out. With this in mind, Franke engineers developed a cartridge system any homeowner can replace without the use of special tools.
Remove the handle of a top lever unit as follows: run the hot water for a minute or two to soften the plastic handle seal and pull the lever straight off the square shaft without undoing any screws. Place a cloth over the exposed domed cartridge housing, grip the housing with channel pliers and unscrew it in an anticlockwise direction to expose the cartridge. Turn off both hot and cold water shut-off valves situated against the wall under the sink before removing the cartridge.
Disconnect the handle on a side-mounted unit as follows: Turn off the hot and cold water shut-off valves under the sink. Insert the corner of a flat head screwdriver into the slot below the red and blue indicator on the front of the handle. Pry the indicator out to reveal the underlying handle retaining screw. Undo the screw with the flat screwdriver, alternatively, if you have an older faucet fitted with a black handle, remove the retaining screw with a 3 mm Allen wrench and pull the handle off the square shaft.
Squeeze the domed cartridge housing from both sides by hand and pull it off to expose the cartridge secured with a brass retaining nut. Grip the brass retaining nut with a Stillson wrench. Loosen the nut in an anticlockwise direction, spin it off by hand, and slide the cartridge out. The seals usually remain in the cartridge during disassembly, however, if they stick inside the housing, remove them. Wipe the polished steel face inside housing clean with a damp cloth.
Line up the locator plug on the replacement cartridge with the matching hole on the face of the housing. Insert the replacement cartridge and twist it both ways to ensure that the locator slips into its matching hole. Spin the brass nut onto the threads by hand in a clockwise direction and snug the nut down with the Stilson wrench. Do not flatten the seals by over tightening the nut.
Clip or screw the domed cartridge back on, depending on the faucet model. With a with a top mounted handle, slide the handle onto the square shaft and push it firmly downward to seat it; with a side mounted model, slide the handle onto the shaft, replace the retaining screw and tighten it firmly. Once this is done, clip the red and blue heat indicator back into place.
Turn the hot and cold shut-off valves back on. Check for leaks and turn the handle both ways to test the action.