Fluidmaster 400 anti-siphon not refilling after toilet flush

Previously I had a fluidmaster 400, I dont remember if it came with the toilet or if a plumber was called to fix it. Anyways, for the past couple months to a year, it has been acting up, I don't rmember how much in detail, but I do know that of recently (at least 2 months or so), the water in the tank would randomly refill. The most recent issue was the water draining right after being refilled and vice versa. After playing around with everything, I found out that whenever I took the water out of the float cup, everything returned back to normal, until the watrer eventually found it's way back into it and then repeat. Well i ended up buying new one and everything seemed to work as it is supposed to. Until I noticed that the water would drain a little bit, and then refill in a rapid succesion. This drainage/refill pattern never happened with the old fluidmaster. Anyways with a little tampering, I managed to stop it. This is when I realised that something was wrong. Now what the toilet does is it may not refill the water past 1/8/1/10 of the tank. So it will appear to be refilling, but water is also being drained at the same time causing the water level to remain the same or refill very very very very very very very very slowly. And how do I manage to get it working again? I shake the water out of the float cup. It hasn't been up to 2 weeks yet. Not only am i upset that this is a new product, im also mad that my brother (who isn't an idiot), for some reason is never aware whenever the toilet is running constantly and never puts in an effort to figure out what wrong with it because he's too concerned trying to learn every ****ing useless word their is to know in the english vocabulary, meaning water will continously be wasted unless I just happen to hear the toilet. And it's ****ed up because he always uses it .

Why is water continously going into the float cup and giving me this problem?

Post A picture of the inside of the tank.

The reason the new Fluidmaster did not fix your problem is because it was/is not the cause of your problem. Replace the flapper and you will solve your problem.

Make sure you don't stick the refill tube down into the overflow tube. it will siphon water from the tank making it seem like a leaking flapper. It requires the air gap clip that came with the unit.

Turn off the water. you can pop off the top with lever arm by lifting arm and turn cap and arm assembly. There is a small diaphragm with a needle sticking out of it. you can pull that off wipe it off and or replace it. before you put it back on put a cup over the top of the 400A , crack open the water to flush it out. Re-assemble.

Check your water pressure.

"ihatefluidmaster"

You may hate Fluidmaster but for many years they have made very good relatively inexpensive toilet fill valves and I have successfully installed them thousands of times. You are blaming Fluidmaster for your lack of plumbing knowledge. That is not their fault. In order to repair any problem, you have to repair the correct parts.

If you do not understand how to repair the flapper, hire a licensed professional.

P.S. As far as your brother is concerned, require him to personally pay the water bill every month. I guarantee after the first bill, he will be going around the house checking everything for leaks.

OK so it turns out that the chain that lifts up the flapper when you press the toilet handle, was getting in the way of the bottom of the flapper which prevented it from closing properly. Now I just make sure the chain doesn't get in between the flapper. I wouldn't be surprised if this is the same problem others might have had especially if the chain connecting the handle and the flapper has been adjusted too long. I'm not sure sure the water was refilling and draining in rapid succession previously, but that doesn't happen anymore so i'm ok with it Probably something with the water pressure level.

So Am I to understand you will change your name to "ilovefluidmaster"?

ihatefluidmaster said:

Probably something with the water pressure level.

Click to expand...

No. Incorrectly installed flapper was the problem.

SHR said:

No. Incorrectly installed flapper was the problem.

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Yet I fixed the problem without changing the flapper...