low pressure light on triton jade shower?

I have a triton jade shower. when you turn it on to any of the 2 heat settings the low pressure led comes on. when you turn it up to maximum heat the low pressure led goes off. as you reduce the settings to cooler the low pressure light comes back on. the shower has been in use for over 12 months and this is the first time this has happened.

dave.1
December 2007