If there is no water flow through your shower this would indicate that the solenoid valve is not opening. This would also cause the low pressure indication.
We have to consider power to unit ie is there still 230 / 240 v present including under load conditions, the switching to the solenoid and solenoid valve itself.
Relevent electrical continuity checks would be required in order to determine the exact cause - parts could then be ordered or alternatively a service visit could be arranged through the Triton Service Dept who may be contacted by telephone on 0844 980 0750 (for service or Spares).
Hope this helps.
Regards,
Karl
TRITON TECHNICAL TEAM
TRITON TECHNICAL
October 2010