How to fix a Caroma oulet valve?

[ColinFryer]

My Caroma cistern works OK if either flush button is held down for a full-length flush.  But if either button is held down for a shorter time, the outlet valve does not close and water keeps running into the bowl. Then pushing the button again immediately and holding for full flush fixes the problem.  Is it likely that I can fix this?  How do I disassemble the mechanism? I know how to remove the float and replace the inlet valve, but I haven't done more than that.

[MikeTNZ]

Hi @ColinFryer,

These are a very simple mechanism that works on spring tension and water pressure.

I suspect that there could be a broken return spring somewhere in the whole mechanism.

My advice would be to turn off the water to the cistern, flush the cistern and check the parts within that "teeter arm" that runs the inlet valve.

Just do this slowly and methodically, be aware of springs flying out from nowhere as you dismantle the thing, especially if there is a broken

spring in there, this is a given.

They are always "compression" type springs, not tension springs.

Also, if you go to a plumbing supplier, there are "service kits" for the Caroma cisterns, that has all the seals, springs etc that you need to service the cistern valves, etc.

I have a Caroma cistern here at home and I had the same issue last year.

If you strike any issues, by all means, let me know, I'd be more than happy to help you out.

Cheers,

Mike T.

[EricL]

Hello @ColinFryer 

Welcome to the Bunnings Workshop community. It's fantastic to have you join us, and thank you for sharing your question about your Caroma outlet valve.

It's great that you've received excellent advice from @MikeTNZ. It could possibly be a return spring that has gone soft inside the flushing mechanism. I've placed an image below showing you where the four locking pins are that will release the flushing mechanism and allow you to pull it out. Please note that these pins might be brittle so if you don't wish to take the risk, I suggest engaging the services of a registered plumber.

Please note that the outer shell of the flushing mechanism can't be removed, and it stays inside the toilet. Only the interior part along with the flush buttons will come out. Once you have the flushing system out, you can examine the parts and replace the faulty springs. 

However, if after replacing the springs and the unit still gets stuck, odds are a fine film of calcium has developed over the outer skin of the plastic. This calcium acts like sandpaper and when sliding plastic pieces come together, they get stuck on one another. If that is the case, it will need to be replaced as washing the plastic pieces will not remove the calcium deposit.

Please makes sure to wear personal protection such as disposable latex gloves and goggles when working on the flushing mechanism. 

If you have any other questions we can help with, please let us know.

Eric