Locate the filling loop (usually underneath the boiler), open both valves slowly until the pressure gauge reads 1–1.5 bar, then close the valves and check for leaks.

65–70°C for efficiency; lower (50–55°C) for condensing boilers to maximize condensation.

120°F (49°C) is the recommended maximum temperature. Consider installing anti-scald devices on faucets for additional protection.