Roz Posted May 10, 2020 Share Posted May 10, 2020 We've just installed a concealed cistern Grohe with a RAK toilet. The cistern is one with an air tube connected to the flush plate. We've not yet connected the air tube to the flush plate as we just got to the stage of filling the cistern. When we first installed there was a lot of water constantly running into the toilet, but a bit of a wiggle of the air tube reduced this to the point you almost don't notice, but because we were looking, we know there's still a silent trail of water trickling into the toilet, and every 10 minutes or so the cistern drops enough in level to pull water through the pipes to fill it a little. We've tried some more wiggling of the air tube, I don't know if it could have perhaps gotten water or dust in it... or if there is a fault with this or something else in there. any ideas of what we should do? Let me know if you want photos of the internals. It was basically this cistern but from somewhere else as it was £140 for the cistern and frame and flush plate. pan from somewhere else https://www.victorianplumbing.co.uk/grohe-rapid-sl-euro-rimless-complete-wc-5-in-1-pack?campaign=googlebase&gclid=Cj0KCQjwzN71BRCOARIsAF8pjfgX87buV5pzucp2yASIyGfvBsCtIj1LPVYJZNj90yT2FctClptIRHsaAohNEALw_wcB&gclsrc=aw.ds Link to comment Share on other sites More sharing options...
Nickfromwales Posted May 10, 2020 Share Posted May 10, 2020 Sounds like the turn screw adjuster on the fill ( float ) valve is set too high and water is getting to the top of the overflow pipe and then discharging to the WC pan. Can you remove the flush plate, and then observe if the water is indeed getting to the top of the internal overflow ? That pipe should be dead centre of the cistern when you look inside. If it’s not getting to that height and the unit is brand new, it’s likely the cistern flush valve insert isn’t seated properly. Check Grohe / YouTube for service info and follow that. They’re quite informative. I fit Geberit routinely so am a not completely familiar with Grohe stuff, sorry. 1 Link to comment Share on other sites More sharing options...
Temp Posted May 10, 2020 Share Posted May 10, 2020 (edited) +1 Unlikely to be anything to do with the air flush pipe. As @Nickfromwales said it could be one of three things.. 1) Float adjusted too high so water goes down the overflow. Unlikely to be this if you can hear it opening every 10 mins. 2) Fill valve leaking so float is underwater and water goes down the overflow. Unlikely to be this if you can hear it opening every 10 mins. 3) Flush valve leaking so so it's letting water past into the pan. Could be dirt in there, try flushing it if not done already. Some are designed to be serviced through the flush plate, others with remote flush buttons you have to provide an access panel. Edited May 10, 2020 by Temp 1 Link to comment Share on other sites More sharing options...
Roz Posted June 20, 2020 Author Share Posted June 20, 2020 OK I'm back!! Ignored this problem for too long I did take a video of this but can't seem to find it. However, my further details are that when you flush the toilet, it now continues to flush and empty the cistern, unless you press on the big white cylinder in the middle, then it stops. Any clue how to fix it? Link to comment Share on other sites More sharing options...
Roz Posted June 24, 2020 Author Share Posted June 24, 2020 Any plumbers fancy explaining the fix for this to me? I have looked on youtube! Link to comment Share on other sites More sharing options...
PeterW Posted June 24, 2020 Share Posted June 24, 2020 The flush tube is catching on something. Turn the isolator valve off. Reach in and turn the white tube and it’s mechanism 1/4 turn anti-clockwise. It will then come up and out in your hand. Check the mechanism and the washer and then refit it - it will click into place. Refit the flush mechanism and retry it. 1 Link to comment Share on other sites More sharing options...
Onoff Posted June 24, 2020 Share Posted June 24, 2020 Is that a big lump of crud I see in there? Hard water scale etc maybe. The flush tube maybe not seating properly. It's supposed to drop down and seal after flushing. Removal and refitting might be all it needs. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 24, 2020 Share Posted June 24, 2020 (edited) In a video I saw, the rubber seal at the bottom of the flush pipe ( the bit you're pressing down on to stop the water flowing ) got taken off and flipped over and re-fitted. Simple fix hopefully. Check that where the two surfaces meet there is no 'crud' otherwise you're not going to resolve this. Do you have very hard water? Edited June 24, 2020 by Nickfromwales 1 Link to comment Share on other sites More sharing options...
Roz Posted June 26, 2020 Author Share Posted June 26, 2020 Thanks @PeterW @Onoff @Nickfromwales Should I empty the cistern first before taking off the flush pipe ? We have soft water here, but some crap might have gotten in there at some point, I'll check! Link to comment Share on other sites More sharing options...
PeterW Posted June 26, 2020 Share Posted June 26, 2020 No just switch the fill valve off - it will flush as you pull the pipe out 1 Link to comment Share on other sites More sharing options...
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