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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 designed as a direct replacement for TOTO dual flush toilets. Sourcing an authentic TOTO replacement part ensures proper seal integrity, correct flush volume calibration, and long-term reliability — critical for property managers and contractors who need the repair done right the first time.
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
- Durable construction for long service life in residential and commercial applications
Compatibility
Designed 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:
- Replacement Parts
- Department:
- Plumbing
TOTO THU777S-A – Frequently Asked Questions
1) What is the TOTO THU777S-A flush valve assembly used for?
The THU777S-A is a replacement flush valve assembly for TOTO toilets. It controls water flow from the tank to the bowl during flushing cycles. This assembly includes the valve seat, flapper, and connecting hardware.
2) Which TOTO toilet models is this flush valve compatible with?
This assembly fits specific TOTO toilet models. Check your toilet's model number and tank markings before ordering. The valve seat diameter and mounting configuration must match your existing tank design.
3) How do I measure my existing flush valve for replacement?
Measure the diameter of the flush valve seat where it contacts the tank bottom. Standard sizes are 2-inch and 3-inch. Also check the height clearance from seat to tank lid for proper flapper operation.
4) What tools are needed to install this flush valve assembly?
Installation requires adjustable pliers, a spud wrench or large channel locks, and possibly a hacksaw for chain adjustment. Turn off water supply and drain the tank completely before starting work.
5) Can this valve assembly be installed without removing the toilet tank?
Tank removal is typically required for proper flush valve replacement. The large locknut underneath the tank must be accessed to secure the new valve assembly. This ensures proper sealing and prevents leaks.
6) How do I adjust the flapper chain length after installation?
The chain should have slight slack when the flapper is closed. Too tight prevents proper sealing. Too loose prevents full opening. Adjust chain length so flapper lifts completely during flush but seals firmly when closed.
7) What causes flush valve assemblies to fail?
Common failure causes include mineral buildup preventing proper sealing, warped or cracked flappers allowing water leakage, and deteriorated valve seats. Hard water accelerates these issues requiring more frequent replacement.
8) Are there any plumbing code considerations for flush valve replacement?
Most codes allow homeowner flush valve replacement as routine maintenance. However, verify local requirements if making modifications to tank or bowl connections. Use only manufacturer-approved replacement parts.
9) How often should TOTO flush valve assemblies be replaced?
Replace when experiencing continuous running, poor flush performance, or visible wear. Typical service life is 5-7 years depending on water quality and usage frequency. Inspect annually for proper operation.
10) What other TOTO parts might need replacement during this repair?
Consider replacing the fill valve, tank-to-bowl gasket, and tank bolts if they show wear. The flush lever mechanism may also need attention. Replacing multiple components together reduces future service calls.
11) Can this assembly be used with non-TOTO toilet tanks?
This assembly is designed specifically for TOTO toilets. Using with other brands may result in improper fit, poor performance, or leakage. Stick with manufacturer-specified parts for reliable operation and proper warranty coverage.
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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