Hi I have a baxi bermuda inset 50/5, fitted about 6 years ago, had big problems last year but after sevice and a new pcb fitted everything seemed ok. Problem now is boiler when shutting down goes to red fault light, boiler will only stay lit 3 mins. max. boiler cannot be reset to amber light by turning control (potentiometer) its as if this control no longer works, could this be a faulty pcb or a bad connection?