Aqualisa shower cartridge- luke warm water?

It's most likely that your pump is cavitaing or possibly pulling air. Does the hot feed coming from the pump - feeding the shower feel hot to the touch?
If you have a flexible handset and hose- remove the head from the hose - lower the end of the hose into the tray or bath, set the temp dial to full cold and turn the shower on. Gradually blend in the hot supply. If the water starts to surge or splutter - stop moving the temp. lever until the flow settles. Keep moving the lever till you get to the full hot setting, then do the opposite till you reach the full cold position. You can check your open vent pipe also to see if you are getting any suction - this would then point to a restrcition somewhere in your pipework. You can also check the filter on the hot inlet to the pump.

G-Man
April 2009

Hi Ryan

The cold water supply should come from the header tank and not the mains otherwise the pressures of hot and cold will not be equal. This could be something to check.

Dr. Bob
April 2009