Toilet runs when shower is on.

[Marples]

I have a problem with a toilet, directly behind this in another room there is a shower and i'm assuming they are both connected. The bathrooms are fully tiled so accessing the pipework isn't really an option.

The problem is that when the shower is on, the toilet keeps running. Not all of the time though.

I had a wild guess and thought that the pressure would be higher because of the shower running which is forcing water through to the valve. am i right? also what is the solution?
Thanks.

 

[Ray Stafford]

Is the shower pumped?

 

[Marples]

I'd say yes.

 

[Ray Stafford]

My guess is that the WC cistern was probably originally tank fed, and therefore has a low-pressure seating in the ballvalve.

When the shower pump was fitted, rather than just pumping the shower, its sited in such a way that it pressurises the ballvalve in the WC cistern as well. When the shower is in use, the flowswitch kicks the pump in, and the pressure on the low-pressure seating is too great, so it forces the ballvalve to fill the cistern, which is then overflowing internally.

Just a guess from a desk jockey - the real plumbers will be along later.

 

[Neil K]

Rays right. Change the ballvalve in the wc for a high pressure one

 

[Marples]

Sounds exactly like what is happening. What would the solution to that be? New ball valve that can cope with the pressure?

 

[Ray Stafford]

Sounds exactly like what is happening. What would the solution to that be? New ball valve that can cope with the pressure?

If its an old fashioned ballvalve, it may have a little plastic seating in it like this

Swap it for a high pressure seating like this

Or just change the whole thing.