no because the water pressure is not activating the pressure switchBut if water is coming out, but it is not getting hot, and it is supposed to use electricity to heat it- Do you not agree the electricity could play a part in why it is not working?
to activate the micro switch which will close the circuit for the heating elements.
but the op fitted and commissioned the shower not a plumberAs above, I would work with the plumber (if one is there, and can speak in plain english) on site to solve the problem.