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.

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 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. 😊

[bryanhuang]

This video has probably saved me £300 - thank you David! Extremely well documented, my toilet set up is is exactly as mine is. You calmly explained everything and as someone with ZERO experience plumbing or anything DIY you were reassuring where things can move around. this has to be one of the best instructional videos! 🙏

[shapneil]

Just a note of thanks for this. Struggled for half a day and got nowhere with a constantly running flush. Watch your video and everything clicked into place, literally. Much appreciated.

[FreddieDobbs]

Thank you so much for this- I had a quote of £450 from a plumber to fix this issue! I then watched your video, bought the part for £26, and it worked! Thank you!:)

[kfbejoyable]

are you a science teacher by any chance.A very elaborate, scientifically & logically explained video.I live in a house made by Bellway.They didn't even know the brand of the cistern they installed..Your video is a life saver...Most plumber don't even want to attempt a repair....Thanks a lot

[btcbiker]

Thank you very much for posting this video. We live in Hertford and have been messed about by a plumber for over a week. I've ordered the parts and going to do it myself. I have liked and subscribed to your channel. Thank you again.

[hertfordbuildingservicesma]

I didnt expect to be able to find this video, but thank you so much for doing it.
Brilliant

[OGH]

My man. You are God send. Thank you. Valve replaced and toilet flushing like a dream

[pcg]

One of the best demonstrative videos I've seen in a while, .looking forward to the next one, thanks.

[michaelantipin]

Thanks David! This saved me the second time! I forgot some steps of disassembling the thing. Great job! (I'm in Mellor and we have the very same system.)

[richfoster]

Fantastic video. Thought I’d have to remove tiles with this system, but the guide was perfect. Thanks!

[seyvend]

A legend among men, thank you so much sir

[stevem]

You made my day with this video. Excellent in all respects. YT needs more of you. Thanks : )

[leenilsson]

Thanks David, just took me 5 minutes to install following your brilliant video

[snapshotsreviews]

Thanks was waiting for the parts, they arrived today and I have not fixed the issue thanks to your amazing video thanks

[michaelwray]

Excellent. My toilet interior is pretty much identical to yours so I have just used this instructional video to fix my leaking cistern. In my case, the seal had bubbled (which I knew to look for thanks to another video) and produced water blisters. I used a pin to prick those bubbles, followed your video to reassemble and now it all works. I expect it's only a matter of time before I need to replace the seal altogether but I now know how to do that when the time comes. Thanks!

[woodencanoe]

This was very useful. I dismantled the unit and found that the “click” is due to a pair of magnets fixed on plastic tabs on the base of the main unit. They had become detached and were stuck to the metal plates on the bottom styrene float. I detached them and stuck them back with a dab of superglue and the unit is working perfectly again. I have however order a new unit as I am sure the glue will fail with time but it does appear to be a semi permanent fix.

[michaelpluess]

Thanks so much! This was extremely helpful. Not only was I able to fix one toilet by replacing the flush valve following your instructions but I also realised that one part was missing in the other toilet which I now fixed also. Great stuff!

[scottiep]

Thank you for this awesome demonstration and talk through David - So incredibly useful!

[pcg]

The guys that design these mechanisms are pretty smart.

[jamesmorgan]

Thanks David, able to save on excessive plumber bill by doing myself. Appreciate it!