Have a triton 100e thermostatic electric which is a disaster due to low mains pressure at times, we decided to move shower to different wall and hooked it up to a direct feed from tank in the attic to see if this would sort pressure problem. Shower came on, started to heat water then tripped out due to lack of pressure, eventually re-plumbed back onto mains water. The shower is now coming on, pumping the water no problem however the water is not heating up....any ideas what may be the problem and how to sort????