Replacement Shower Mixer Valve

[camdenl]

I am currently refitting our ensuite bathroom which involves ripping out the old shower and replacing it.

As part of this I am replacing the shower mixer valve (the old one leeks, which has resulted in the tiles coming away from the wall and is the cause of this complete project. Also my wife does not like it) with a new low pressure thermostatic valve. The existing valve is fed by 15mm copper pipe for both the hot and cold water. The cold water feed comes directly from the tank in the loft and the hot water feed from a dedicated connection in the hot water cylinder.

The problem that I have is that the new valve should connect to 22mm pipe for both the hot and cold feeds. Is it OK to connect these to the existing 15mm pipes using a 22mm - 15mm reducer or should complete shower feed system be replaced by 22mm copper pipe? Would using the existing 15mm copper pipe have a negative affect on the performance of this low pressure thermostatic valve?

Any advice/ideas given would be greatly appreciated.

 

[Softus]

The problem that I have is that the new valve should connect to 22mm pipe for both the hot and cold feeds. Is it OK to connect these to the existing 15mm pipes using a 22mm - 15mm reducer or should complete shower feed system be replaced by 22mm copper pipe?

Depends - how high above the shower head is the bottom of the cistern that's supplying the water?

Would using the existing 15mm copper pipe have a negative affect on the performance of this low pressure thermostatic valve?

Yes, but whether that effect is enough to be noticed depends on the head - please see above.

 

[camdenl]

Thanks for your reply.

The shower head is 4ft below the bottom of the water tank.
The mixer valve is approximately 6ft below the bottom of the water tank.