Aqualisa showers are fitted with a bi-metallic spiral cartridge which uncurls and lengthens as it heats up due to the hot / cold water passing through it. This allows the cartridge to limit the hot / cold inputs in the thermostatic mixer part of the shower body ( its very hard to explain without drawing a diagram ).
Although the Aqualisa is a very expensive thermostatic shower ( New cartridges are approx £ 80+ plus vat ) they suffer from a very serious problem in hard water areas. Limescale badly effects them and renders the cartridge mechanism useless after a short while.
If you have noticed a decline in the flow through the shower over the last few months then it is safe to say that the cartridge is clapped out and needs replacing as the limescale has now completely encased and stopped the bi-metallic spiral from functioning and letting the water through.
If you are reasonably good at things around the house then this job is not difficult, to get at the cartridge you have to remove the centre part of the mixer assembly fixed to the shower wall .Do a google search for your aqualisa model on the net and you should find an exploded view showing the various parts and the order of assembly.
Try this link for the cartridge for your particular model.
Good luck.
http://www.showerright.co.uk/aqualisa_replacement_thermostati.htm
John ( Wirral ), August 2008
