How To Replace A Fill Valve

Step 1: Shut off the water supply to the tank by turning the supply knob to the off position. The water supply is located behind the toilet, coming through either the wall or the floor. If you do not have a shut off, turn off the main water supply for the home.

Place a few towels around the back and sides of the toilet. With the water turned off, you will begin to empty the tank. Carefully remove the tank lid and set it aside. The tank water can be conserved by using a small cup to empty it into a bucket. The water can then be used to water a plant, for example. Or, you can simply hold the flush lever down to flush as much of the water out of the tank as possible. Use a sponge or a few rags to soak up the rest of the water in the tank.

Disconnect the refill tube from the flush valve. Use a pair of channel-lock pliers to loosen the nut connecting the water supply line to the toilet, which is located on the underside of the tank. There will be a small amount of water in the supply line when you remove it. Then remove the jam-nut that holds the fill valve in the tank. Next, remove the old fill valve assembly from the tank.

Step 2: If you have the Fluidmaster Flush 'n Sparkle bowl cleaning system, carefully disconnect the tube from the fill valve. Do not disconnect the tube from the dispenser. If you do not have this system, move on to the next step.

Step 3: Disassemble the small parts: lock nut, angle adapter, cone washer, shank washer and coupling nut for valve installation. The shank washer and cone washer are molded together as one piece. Gently pull the shank/cone washer off of the angle adapter and this will release the lock nut, coupling nut, and angle adapter.

Step 4:Carefully remove the cone washer from the center of the shank washer. Place the shank washer on the threaded shank of the new valve with the flat surface against the valve. The cone washer can be used with the coupling nut on the water supply line to be attached to the threaded shank as shown in step 8.

Step 5: When installed, the "critical level" mark on the fill valve should be at least 1 inch above the top of the overflow pipe. This is a plumbing code in many areas. The critical level is identified by a "CL" mark on the Fluidmaster 400a Fill valve.

Step 6: To adjust the height of the fill valve, twist the threaded shank in or out of the valve body. The height of the Fluidmaster 400a valve adjusts from 9 to 14 inches. On some models a clicking noise will be heard when adjusting the height, this is normal.

Step 7: Position the valve inside the tank. Push down on the valve shank (not on the top) while tightening the lock nut. Hand tighten only - DO NOT over-tighten or the tank may crack. Make sure the float cup does not touch the tank walls, trip mechanism, or flush valve.

Step 8: Before continuing, determine the type of water supply connection you have from the chart and use the appropriate assembly parts required to properly reconnect the water supply. Do not use plumbers putty to seal these fittings.

Step 9: With the correct washers in place, tighten the coupling nut. Hand tighten only - be careful not to over tighten. Do not use the cone washer with a plastic supply line. The cone washer and coupling nut will not be needed if using stainless steel braided connectors.

Step 10: If you have a Fluidmaster bowl cleaning system, re-attach the IN tube to the fill valve nipple. Be sure the toilet tank flushing components move freely.
If you do not have the cleaning system, move on to the next step.

Step 11: Attach one end of the black refill tube to angle adapter and the other end to the nipple located near the top of the valve.
NOTE: Flow from the refill tube must be positioned just above the overflow pipe. Do not insert the refill tube down into the overflow pipe below the water level. This will cause water to siphon out of the tank, down the overflow pipe, causing the valve to turn on and off as it tries to keep the tank full. The air gap provided by the use of the angle adapter prevents this.

Step 12: It is very important to always clear sand, rust and other debris from the system before completing installation. Make sure the water supply is shut off. Then remove only the cap on top of the valve by lifting the arm and rotating the cap and arm 1/8 of a turn counterclockwise, while pressing down slightly on the cap.

Step 13: While holding a container over the uncapped valve to prevent splashing, turn water supply on and off a few times. This will flush any sand, dirt or rust out of the fill valve. Leave the water supply off.

Step 14: Replace the cap by engaging the lugs and rotating 1/8 turn clockwise. Make certain the cap is turned to the locked position, or else the valve may not turn on.

Step 15: Turn on the water supply and then adjust the water in the tank to the desired level. Some models will adjust by squeezing the water level adjustment clip and moving the float cup up or down along the stainless steel link. On other models, the water level adjustment rod operates like a screw - unscrew to move the rod up or screw-in to move the rod down. Check for leaks, then check for proper flush. Then, pat yourself on the back - you've successfully replaced your fill valve!