How to Stop Schwab Fluidmaster 187.1200 Concealed Cistern from Continuously Flushing

Having problems with your Schwab toilet continuously flushing? This video shows how to make the repair, and covers a few different issues that may arise. In this instance I replace the faulty flush valve (outlet valve), but discuss two other possible causes, namely hard-water deposits on the valve seat and worn valve seal. Although this repair is specific to the Schwab (Fluidmaster) model 187.1200, the principle is the same for any concealed-cistern toilet, although parts and configuration may differ.
Here is a link to the manufacturer’s website, showing the breakdown of parts and part numbers needed to order spares: en.sanitaer-sch...
In the video, I used replacement part 239233 (Outlet valve), and I mention that it’s possible to replace just the valve seal (ie. silicon gasket), which is part number 351517. Please note that the replacement outlet valve comes with a fresh valve seal, so you do not need to order the latter separately (unless you just want to keep a spare on hand.)
I’d like to give a special shout-out to Steve at ToiletSpares.co.uk, who helped me troubleshoot the issue, and can supply the replacement parts mentioned above. I am not affiliated, other than being a satisfied customer. You can search the interwebs for these parts such as “Schwab 239233”, but here are the links to Steve’s inventory:
www.toiletspar... (flush valve)
www.toiletspar... (valve seal)
I hope you found this video to be helpful, and please feel free to ask any questions below. Disclaimer: I’m not a qualified plumber, just a bloke with an engineering mindset, who likes helping people out of their misery. 😊