Geberit Dual Flush Problem

[stevecase51]

I have a Geberit concealed cistern for low height furniture. This has a dual pneumatic flush, and has worked without any problems for a few years. Recently I found that when I push the full flush button, the toilet flushes OK but the button doesn't return fully (i.e. it stays pushed in slightly). The amount by which the button stays depressed increases with each flush so that after a couple more flushes the button stays half in and, if I then try to do a full flush, it only half flushes (and the button stays half in afterwards). If I disconnect the full flush pipe briefly from the back of the push button unit, the button immediately returns to the proper position, and I am back to where I started. I don't want to buy a new push button unit if the problem is the flush control unit and vice versa. Any suggestions appreciated. The half flush (which gets used more than the full flush) works fine.

 

[oz-plumber]

Pull the button mechanism apart and grease / lubricate the walls of the mechanism.

If that does't solve the problem, you may have water in the air tubes.
Disconnect the tube and blow through them.

 

[stevecase51]

Pull the button mechanism apart and grease / lubricate the walls of the mechanism.

If that does't solve the problem, you may have water in the air tubes.
Disconnect the tube and blow through them.

Thanks for these suggestions. I have since discovered that when the full flush button remains depressed (i.e. after a couple of full flushes), if I then use the short flush, it has the effect of re-setting the full flush button. This means I have a work-around solution and there is less urgency to fix the problem. However I will bear in mind what you suggested while I continue to monitor the situation. I have also asked Geberit technical support for their advice.

 

[stevecase51]

Pull the button mechanism apart and grease / lubricate the walls of the mechanism.

If that does't solve the problem, you may have water in the air tubes.
Disconnect the tube and blow through them.

The problem seems to be getting worse, so I need to do something. Could somebody explain how to remove the actuator unit from the flush valve so I can get at the bottom hose connection more easily and, if necessary later, replace the actuator unit with a new one.

 

[oz-plumber]

You should be able to just pull the hoses off.
Some of them have a white joiner piece so you don't have to disconnect the tubes from the flushing mechanism.

You may have a problem with the bellows, if you are saying that the full flush button returns to correct position when you disconnect the tubes.
You may need a new flush valve.

 

[stevecase51]

You should be able to just pull the hoses off.
Some of them have a white joiner piece so you don't have to disconnect the tubes from the flushing mechanism.

You may have a problem with the bellows, if you are saying that the full flush button returns to correct position when you disconnect the tubes.
You may need a new flush valve.

When I swap the hoses at the push button end the problem simply transfers to the half flush button, suggesting that the fault is in the actuator (llifter) that is attached to the flush valve. I have ordered the part, but I'm not sure how to detach it from the valve. I think there is a plastic ring at the top that clips around the overflow tube, but perhaps somebody could confirm this.

 

[stevecase51]

This problem is now sorted. James at Geberit Technical was very helpful. He told me how to remove the actuator and also emailed me a useful install guide. As it turned out, I discovered the problem was not the actuator but a split hose. I did a temporary fix by cutting the pipe a bit shorter, but I have ordered a new hose to do a proper repair in due course. Thanks to those of you who offered suggestions.