'Phantom flushing'

Usually means the flapper valve is leaking into the bowl.

A new valve, or a new valve and valve seat, are the common fix.

Plumber may have replaced the flapper but apparently didn't check to see whether or not it was actually sealing.

I would be surprised to learn your problem was anything other than leaking into the bowl past the flapper. I suspect the plumber addressed the common/obvious/typical cause but didn't stay around long enough to verify consistent seal.

Suspect you're looking at a do-over. However, having myself had some annoying problems similar to yours in the past, there have been several occasions where I "gave up" and just replaced the entire guts. A bit messy and annoying but not complicated or expensive if it comes to that.

Toilets are simple things. Whatever the problem may be, it is diagnosable and fixable.

"Plumber may have replaced the flapper but..." most probably used a generic, universal replacement flapper while some toilets have to have the manufacturer's exact replacement part.

Put a few drops of food coloring in the toilet tank and wait to see if the water in the bowl turns color. When it does, call the plumber and tell him/her to come back and do the job right at no additional cost to you.

Also, make sure the fill valve hose is not pushed down into the overflow tube (should be clipped onto the edge).

The fill valve trap primer line has absolutely nothing to do with this problem and contrary to the popular opinion even if it is down in the standpipe, it cannot syphon water from the tank.

The flapper was just recently changed so there are three common problems to check:

1. Check the length of the chain from the flapper to the flush handle arm. Properly it should be adjusted so there is about 1 or 2 links of slack in the chain. If the chain is too long it gets pulled into the flush valve as water is discharging from the tank and when the flapper drops down again the chain prevents it from sealing.

2. Check the flapper mounts to make sure they are completely on the little arms on the standpipe so the flapper is free to move up and down. If either of the mounts are only part way on the arm that causes the mounts to keep one side of the flapper slightly raised, allowing water to leak.

3. Run your finger nail over the top sealing surface of the flush valve. Quite often those valves get a mineral buildup on the surface and the new flapper cannot seal correctly. If in doubt use a piece of light emery cloth to burnish the sealing surface on the flush valve.

I second justalurker. Probably isn't the right flapper. Lift the tank lid, get the tank number, and cross-reference that with the mfr's recommended flapper. This especially goes for Kohler.

Lazypup, your #1 also has little to do with the OP's problem. If that were the case the water would be running practically nonstop. How come you didn't mention an OEM flapper in your list?

Hey All-Thanks so much for your responses. Will check out brand specific flappers and lazypup,will really try to find out where and what all those things are you are talking about!! Would love to be more knowledgeable about my abode. Thanks again,Jardinista

"Will check out brand specific flappers"

that still assumes the overflow and flapper seat have not been replaced at some point.

Beg to differ on the water not siphoning down the standpipe lazypup. That is exactly what mine was doing as I had the bowl cleaner hose pushed way down in the standpipe below the surface of the water level at full tank. Of course it shouldn't have been doing this but due to age of the mechanisim and seals it was in fact siphoning the tank causing periodic re-fills. Soon after I replaced all the guts.

When Fluidmaster first introduced their universal fill valve replacement units the actual valve was at the base of the fill valve and the trap primer line ran from the base up to the standpipe. With that configuration if the trap primer line was just put down in the standpipe instead of using the supplied mounting bracket they had problems with water being syphoned from the tank up to the standpipe.

As a result the ASTM (American Society of Testing & Materials) changed the standards. PER ASTM standards now ALL FILL VALVES must be installed at or above the "Critical Level".

If you will look in your toilet tank you will find that the manufacturer has either printer or embossed a "Water Level" index on the tank wall, usually in the center of the back wall of the tank.

Per ASTM standard the top of the standpipe MUST BE a minimum of 1" above the water level index and it must be below the fill valve inlet port.

The water fill valve inlet port must be 1" above the top of the standpipe and the "Trap Primer" port must be equal too or higher than the water inlet port.

In this configuration there will be a minimum 2" vertical air gap from the water level to the fill valve inlet port so it would not matter if you put the trap primer line over the side of the tank and ran it to the floor, it cannot syphon water from the tank.

They do now make some bowl cleaner dispensers that are attached to the trap primer so the water from the fill head will pass through the trap primer line to the dispenser, then to the standpipe,,,BUT..both code and ASTM standards are very specific on those units. The dispenser MUST BE hung from the top of the tank wall and the trap primer line MUST rise up from the fill head to the dispenser, then down to the standpipe. No protion of the trap primer line my be below the critical level.

Now let me qualify me previous statement. If the fill valve, standpipe and trap primer line are properly installed it is impossible for water to be syphoned from the tank to the standpipe.

On the other hand, if someone improperly installs a fill valve, flush valve trap primer line or installs any after market attachments such as your bowl cleaner dispenser improperly you can not blame the manufacturer for your problem. The blame rests solely with the hacker who installed it.