Kromschroder Operator-control unit OCU 500-4 84327033

This is a Kromschroder operator-control unit, model OCU 500-4, SKU 84327033, belonging to the control box category. It is a burner control that manages the ignition sequence and enforces safety times for a gas or oil burner. In operation, it reads the air pressure switch and the flame signal, then drives the ignition transformer, the gas valve and the fan. The control governs pre-purge, ignition, fuel admission and flame proving, and locks out on failure.

Parts of this type are selected by exact series and type designation, supply voltage, safety and pre-purge times, flame detection method (ionisation, UV or IR) and the base or plug pattern. A control from one series is normally not interchangeable with another series even within the same brand; a mismatch in safety time creates a safety issue, not merely a performance problem. When replacing a burner control of this class, verify that the replacement matches the existing unit on all parameters listed above, and do not rely on brand or form factor alone.