Brahma Burner control unit NDM31 37542004

The Brahma NDM31 37542004 is a microprocessor-based burner control unit designed for automatic control of two-stage gas and liquid fuel burners with forced-draught air supply and direct ignition. It operates in intermittent mode, providing a pre-purge time of 5 seconds and a safety time of 5 seconds. The unit supports flame detection via ionisation, photodiode, or phototransistor methods, and includes a built-in ignition transformer. It features non-volatile lockout with manual reset, two safety contacts, and a varistor with electromagnetic filter for protection. The control unit has a supply voltage of 220–240 V, a built-in fuse of 4 A, and dimensions of 10.7 x 8.1 x 3.6 cm, weighing 0.2 kg.

When selecting a replacement control box for a burner, ensure that the supply voltage, safety time, pre-purge time, and flame detection method match the burner's requirements. The control box must be compatible with the burner's fuel type (gas or liquid fuel) and stage configuration (two-stage). Check the mounting dimensions and protection class to fit the existing enclosure. Verify the operating temperature range and ensure the control box has the appropriate number of safety contacts for the valve circuit.

Common failures of burner control units include failure to start, lockout without reset, or intermittent shutdowns. If the unit locks out, check for flame detection issues, such as a dirty or faulty ionisation electrode or photodiode. A blown internal fuse may indicate a short circuit in the wiring or a faulty ignition transformer. If the unit does not respond to reset, the microprocessor or internal components may be damaged, requiring replacement.