Boiler runs but cannot reach the set flow temperature; supply temperature remains low.

Safety: Burner adjustments must be performed by qualified personnel with combustion test equipment.

• Check firing rate: Verify that the burner is reaching its design firing rate. For gas, check manifold pressure; for oil, confirm correct nozzle size and pump pressure.
• Inspect heat exchanger: Clean soot and scale from boiler tubes and passes to restore heat transfer.
• Review system flow: Ensure pumps are not oversized and that flow is within Danstoker’s recommended range. Throttling valves may be needed to balance flow.
• Modulation control: Confirm that the modulation signal from the Danstoker controller to the burner is correct and not limiting output.

If output remains low, a combustion specialist should perform a full burner tune-up.