I am not sure if you still have a problem, certainly advice previously given will help , maybe the options given below may help any other users who may come across the same problem in the future.
Although it is difficult to diagnose the cause of the problem accurately without full inspection of the unit concerned I would suggest that we are looking at one or a combination of the following areas :
Shower head blocked
Hose blocked, twisted or kinked
Inlet filter blocked
General restriction of water flow to unit - isolation valves to unit not fully open etc
Internal build up of scale /debris within unit.
During Summer months of higher ambient water temperature it may be necessary to use the appliance on the Economy / lower setting.
Areas as listed above could be checked for any obstruction where possible and the unit could be flushed through on a cold setting with out the shower head in place. This will allow the full flow of water to be flushed through the unit and hose and hopefully flush through any loose debris.
If necessary replacement parts can be ordered through our Spares Dept (Tel : 0844 980 0750 or via our Web Site). Alternatively arrangements could be made for one of our Service Engineer's to visit if you would prefer this course of action.
Best Regards,
Karl Stein
Triton Technical Team
Triton Showers
Triton Technical, February 2011