Let's see who's paying attention on site... Customer says: ❌ Boiler is working❌ Hot water is working❌ Heating isn't coming on What's the FIRST thing you're checking? A) PCB B) Pump C) Heating controls D) Gas valve Drop your answer below before reading the comments 👇 The best engineers don't just know the answer... They know WHY. I'll reveal the answer later today.