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FLUSH VALVE ASSEMBLY
Manufacturer Resources
Product Specs
- Product Group:
- Washroom/Bath Accessories
- Product Subgroup:
- Parts and Accessories
- Product Type:
- flush valve
- Parts and Accessories Type:
- Flush Valve
- Department:
- Plumbing
- Application:
- Toilet
TOTO THU789-A – Frequently Asked Questions
1) What part number do I order for a TOTO flush valve assembly, and is there more than one version?
Order it as TOTO THU789-A. There is one configuration only, so there are no size, finish, or handing choices to specify. TOTO service parts are model specific, so match the THU789-A number against the parts callout for your toilet before ordering.
2) Will the TOTO THU789-A flush valve fit any toilet, or only certain TOTO models?
Treat it as a TOTO-specific service part. Flush valve assemblies are matched to the tank's opening and overall height, so the THU789-A is intended for the TOTO tanks that call out that part number. It is not a universal replacement for another brand's tank and it will not substitute for a generic hardware-store flush valve kit.
3) What is the TOTO THU789-A?
The THU789-A is a TOTO flush valve assembly, the internal tank valve that releases water from the tank into the toilet bowl on a flush. It is a toilet repair part, not a complete tank or toilet.
4) I manage apartments with TOTO toilets that run constantly. Is replacing the flush valve the right fix?
A toilet that keeps refilling on its own is usually leaking past the flush valve seal, so the flush valve assembly is the normal repair. The THU789-A replaces that whole assembly rather than just a seal, which is the cleaner fix across a fleet of units. If the water is instead running out the overflow, that points at the fill valve, not this part.
5) Does the THU789-A flush valve include the flapper and gasket, or do I need the fill valve too?
It is sold as a flush valve assembly, so it covers the valve body and its sealing components as supplied by TOTO. It does not include the fill valve, the supply line, or the tank-to-bowl bolts. If you are rebuilding a tank completely, plan on the fill valve as a separate part.
6) Do I have to shut off the water and pull the tank to install a TOTO flush valve assembly?
Yes on the water. Shut the supply, flush to empty the tank and sponge out the rest. On most two-piece toilets the tank has to come off the bowl to get at the flush valve nut and the tank-to-bowl gasket, so budget a new tank-to-bowl kit if the old gasket is hardened. One-piece models are worked from inside the tank.
How fast can I get the TOTO THU789-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 THU789-A come with a warranty?
Absolutely. The TOTO THU789-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 THU789-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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