This afternoon my partner ran the shower and you guessed it, freezing cold water again until she ran the hot water bath tap and hot water then came out of the shower head. This evening I have tried running a shower to test if it was still malfunctioning and it is. Every time I turn the shower head off it doesn't matter if I wait 5,10,15, or 20mins before turning the shower back on, I have to go downstairs change the position of the stopcock until I get a decent water temperature, only when the shower is on the 'high' setting. There is no constant hot water on any stopcock position or shower setting, when I run the cold tap for the bath and turn that off the water temperature becomes scorching ht and altering the temperature control doesn't reduce the scolding hot water until it then just turns to freezing cold (probably the heating elements cutting out due to the temp being too high).
I know very little about any of this stuff and DIY so any help is much appreciated no matter how insignificant you may feel it is. From just the basics I am certain that the shower fitted is fine and working and that through the various troubleshooting methods there is a water pressure issue, which I assume is that the pressure is too high and the flow rate too fast for the heating element in the shower block to warm the water up before being expelled out the shower head. Juts an FYI, it is mains fed there is no tank or pump installed in our house.
I've asked the guy who installed if he knows what is wrong but does not know and has advised me to contact Triton customer service. I was just wondering if anyone here might be able to provide more insightful and quicker advice than a customer service operator.
Thank you for your help in advance!