Hello,
Sounds like the pressure relief device has blown. This happens when there is a blockage in the head or the hose is kinked or similar. The part number you need is 83301330. You can purchase these from us for £5.86 all inclusive. You can call us on 0845 126 4141 and order, or follow the link below to take you to the relevant part on our web site:
http://www.showerspares.com/products/spare_parts/triton_pressure_relief_device__83301330
NATIONAL SHOWER SPARES, July 2008
