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TOTO THU777S-A Flush Valve Assembly for Dual Flush Toilets
The TOTO THU777S-A is a genuine OEM flush valve assembly and a direct replacement for TOTO dual flush toilets. Using an authentic TOTO part ensures correct seal integrity, factory-specified flush volume calibration, and a fit that requires no modification.
Key Features
- Genuine TOTO OEM replacement flush valve assembly
- Engineered for TOTO dual flush toilet systems
- Maintains factory-specified flush performance (partial and full flush modes)
- Direct drop-in replacement - no modification required
Compatibility
For use with TOTO dual flush toilet models that specify the THU777S-A flush valve assembly. Verify your toilet model number before ordering. Refer to your toilet's installation guide or TOTO's parts lookup for confirmed compatibility.
Specifications
- Part Number (MPN): THU777S-A
- UPC: 739268188563
- Brand: TOTO
- Part Type: Flush Valve Assembly
- Application: Dual Flush Toilet
Why Order from ZenSupply?
ZenSupply stocks genuine TOTO replacement parts with transparent pricing and fast, free shipping, so your repair stays on schedule. No waiting on distributor back-orders or guessing on compatibility.
Manufacturer Resources
Product Specs
- Product Group:
- Washroom/Bath Accessories
- Product Subgroup:
- Parts and Accessories
- Product Type:
- Dual Flush Valve
- Parts and Accessories Type:
- Flush Valve
- Department:
- Plumbing
- Product Brand:
- TOTO
- Application:
- Toilet
TOTO THU777S-A – Frequently Asked Questions
1) Will the TOTO THU777S-A flush valve fit my TOTO dual flush toilet?
The THU777S-A is made for TOTO dual flush toilets that call out this exact part number, and on those tanks it drops straight in with no modification. TOTO changed valve geometry across model generations, so match the part number against your toilet's model number in its installation guide or TOTO's parts lookup before you order. If your toilet specifies a different THU number, this one is the wrong valve.
2) Will a replacement flush valve keep both the partial and full flush working?
Yes, and that's the reason to use the OEM valve here. The THU777S-A is built for TOTO's dual flush system and holds the factory-specified flush volume calibration for both the partial and full flush modes. A generic valve can seal the tank but still change how much water each button releases, which is what puts a low-flow toilet out of spec.
3) Which part of the toilet tank is the THU777S-A, the flush valve or the fill valve?
It's the flush valve assembly, the unit that sits in the center of the tank and releases water into the bowl when the button is pressed. The fill valve is the separate part on the side of the tank that refills after the flush, and this does not replace that. The photo shows the complete assembly with its dual flush mechanism, red actuator wire, green top cap, and the threaded base seal that mates to the tank opening.
4) Is it worth buying the genuine TOTO part instead of a universal flush valve for a running toilet?
For a TOTO dual flush tank, yes. The THU777S-A is genuine TOTO OEM, so the seal seats correctly on the tank opening and the flush volume stays at the factory calibration. Universal valves are sized for conventional single-flush tanks and don't carry the dual flush actuator arrangement, so a running-toilet repair on a dual flush unit usually ends up back at the OEM assembly anyway.
5) I manage a building with several TOTO dual flush toilets. Can I stock one flush valve for all of them?
Only if they're all the same toilet model. TOTO specifies flush valves per model, and the THU777S-A covers the dual flush toilets that call out that number. Pull the model number off each tank first, then stock the valve that matches each one. Buildings that were fitted out at the same time usually run a single model, in which case one part number covers the fleet.
How fast can I get the TOTO THU777S-A delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the
continental
U.S.
Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit,
reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the TOTO THU777S-A come with a warranty?
Absolutely. The TOTO THU777S-A is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the TOTO THU777S-A?
You can call, text, or email our expert support team for fast answers. We’re here to help with
product
selection,
installation tips, and troubleshooting. Contact Us
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