TOTO Ultramax tank level drops

[Geoffrey Leach]

This is a 13 year old Toto Ultramax 1 CST 854. After replacing the fill valve and flapper with Toto-branded parts, the tank level drops slowly until the valve kicks in and refills the tank. The drop is about 1".

What may be related, there is a sometimes-associated noise in piping that is about 15 feet upstream; tick-tick-.... sounds like a valve opening/closing, except that there is no valve. The toilet is the last connection of the branch.

I've put coloring in the tank to check if there is a leak into the bowl. No luck.

Water pressure is 60-40 with a pressure tank. There's a Takagi tankless water heater in the circuit. It is not running when the problem occurs.

 

[Reach4]

This is a 13 year old Toto Ultramax 1 CST 854. After replacing the fill valve and flapper with Toto-branded parts, the tank level drops slowly until the valve kicks in and refills the tank. The drop is about 1".

1. Close the stop valve at the wall, and see where the level keeps dropping. The level will probably be at the seat of the flapper, but could be lower. Where does it stop?
2. As the water level approaches the level of the valve seat, you could drop a couple drops of coloring, and see where the flow is going. The water should be still to avoid mixing the coloring.
3. Does the tick happen if the fill valve is closed?
4. Does the chain pull the flapper straight up?
5. Does the chain have a couple links of slack, or is it pretty straight?

 

[Sponsor]

 

[Terry]

I use the Korky 3060 for the fill valve on those.

Also, make sure that the fill tube is not down the overflow, but it held higher than the top by the clip.