Toto Aquia CST416M Weak flush

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New Member
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New York
Hi Terry. First off, great forum, I come here all the time. My latest project is trying to figure out why my toto Aquia CST416M toilet has a weak flush. Here are some things to note:

1. I just installed a brand new fill valve, Toto brand TSU99A.X exactly as per the instruction. I notice that some water dribbles out of the blue cap. Safe to assume this is normal? Also hear some gurgling and see some water bubbles come from the bottom of the stem when I flush.

2. The toilet never clogs, so I'm ruling out a blocked trap/drain

3. The pushrods for the buttons are at the longest possible setting before the toilet will start flushing on it's own when the lid is placed on the tank.

4. If I hold the full flush button down 1/4 of a second longer, the flush gets better. The partial flush does not completely empty the bowl. Is this normal?

I didn't do anything with the flush valve. Are there any adjustments for that? What do you recommend?

Thanks in advance.



Wise One
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New York, NY
I'm thinkin' maybe raise the water height a little bit? That will give you a little more water. The partial flush should replace what's there, but in the Aquia, you often don't get the gurgle that you get with a siphon-jet toilet (the Aquia is a "washdown flush", so it behaves a little differently). But if you pour (or otherwise deposit) a colored liquid into the bowl, the water should be clear at the end of the "urine only" flush.
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