Boiler runs but does not provide enough heat to the radiators or underfloor system.

Safety: Surfaces and water may be hot. Use caution when bleeding radiators or touching piping.

• 1. Check setpoints: Verify the Noritz boiler's heating temperature setting is appropriate for your system (consult manual). Increase within safe limits if too low.
• 2. Bleed air: Bleed air from radiators, manifolds, and high points in the system to restore full water circulation.
• 3. Verify pump operation: Ensure the system circulator pump is running when there is a call for heat. Listen for pump noise and feel for vibration.
• 4. Check mixing valves: Confirm any mixing valves are not stuck in a low-temperature position.
• 5. Professional assessment: If output remains low, a technician should check boiler modulation, pump sizing, and system design.