E10 on display, unit will not fire; pressure gauge may read low or zero.

Warning: Hot water under pressure can cause burns. Allow system to cool before opening any valves or vents.

• 1. Read system pressure: Check the hydronic pressure gauge. Most systems require around 12–20 psi when cold.
• 2. Open fill valve: Slowly add water until the gauge reaches the recommended pressure.
• 3. Bleed air: Air in the system can cause false readings. Bleed air from radiators and vents. Top up pressure if it drops.
• 4. Inspect for leaks: Look around the boiler and relief valve for signs of leakage.
• 5. Check pressure sensor wiring: Locate the electronic pressure sensor and inspect its connector.
• 6. Sensor test/replacement: If the gauge shows normal pressure but E10 persists, the sensor may be faulty.