Can't adjust the height of the Fluidmaster

First shut water off at stop than flush all the water out of the tank next take a sponge and get all the water out of tank next unsrew the supply line from the valve under tank than move out of the way next unsrew the nut on the valve of fluidmaster than pull the fluidmaster out of tank stick the new fluidmaster in tighten nut srew the supply line back on turn on stop and let the tank fill up thats it if the fluidmaster dont shut off press the handle let some water out and adjust the fluidmaster screw Tip the water should stop a 1/4 inch below the flush valve tube in center of toilet

fluidmaster 400 adjustment YouTube

you pull up on the gray band than slide the top portion up or down than push the gray band back down to lock

Hello! The vacuum does not move up and down when you change the height setting. When the handle is reclined is when the height of the nozzle will adjust. Hope this was helpful!

The fill valve sounds if it is bad.Go to lowe's and get a fluidmaster fill valve(about $8) instructions included.turn off water and remove water from tank then disconnect supply tube,remove old fill valve install new,follow installation diagram,and the adjustment process to adjust the water level to correct level that should take care of your problem.

Hello- If you replaced old ball and rod set with new fluidmasters they will most likely need to be adjusted, not all toilet tanks are of equal height. You will have to adjust water height,meaning you must keep water level below fill tube located in center of the toilet tank. Adjustment is done from bottom of the fluidmaster, they screw in and out to adjust height. You will notice threads along the bottom part of the fluid master, on the inside of the tank,they adjust up & down! Goodluck!

Try lifting the float part of the valve. If the water stops filling, reset the float level lower.
If water does not stop when lifting the float, flush out the valve according to the instructions - steps 12 - 15.

12. IMPORTANT: Always clear sand and rust from system. Make sure

water supply is shut off. Remove valve TOP by lifting arm and rotating

top and arm 1/8 turn counterclockwise, pressing down slightly on cap.

13. While holding a container over the uncapped VALVE to prevent

splashing, turn water supply on and off a few times. Leave water

supply off.

14. Replace TOP by engaging lugs and rotating 1/8 turn clockwise. MAKE

CERTAIN TOP IS TURNED TO THE LOCKED POSITION. VALVE MAY

NOT TURN ON IF TOP IS NOT FULLY TO THE LOCKED POSITION.

15. Turn on water supply. Adjust water to desired level by squeezing water

level adjustment clip and moving FLOAT CUP up or down along stainless
steel link. Check for leaks, then check for proper flush.

If valve continues to run:

IF FILL VALVE WON'T TURN OFF,

• There may be debris at seal - repeat Steps 12-15.

• The seal inside the valve top may be damaged -replace with genuine
Fluidmaster 242 seal.

The installation instructions are usually printed inside the package. Open the box fully (saves paper) Here is a link to the instructions: https://aruntx.com/conference/kit.pdf
When you say to calibrate the unit, I'm assuming you're referring to adjusting the water level? You can do this by either adjusting the height or the float water level adjustment or both. These are quality trouble free units, I've never had any problems with fluidmaster products. There is a large warning on using Chlorine cleaners (inside the tank) in the instructions. Chlorine cleaners in the bowl are no problem. I've used the tablet type in the tank though without any problem. There would be a problem if the toilet was not used regularly and the tablet continued to dissolve, causing the chlorine level to rise dramatically.

Should be able to grap shaft of valve and twist it to adjust height or remove a cilp on a rod to shorten fill height of valve so it doesn't run down overflow.