De Dietrich 88065536 Diematic 3 relay cards

The De Dietrich 88065536 Diematic 3 relay card is an electronic control board (PCB) intended for De Dietrich boilers. It forms part of the Diematic 3 control system. The catalogue lists it under manufacturer codes 88065536 and 336.568.003. Parts of this type perform the logic and safety functions of a modern wall-hung boiler. The board receives signals from the room thermostat, temperature sensors, and pressure switches, and in turn activates the fan, ignition transformer, gas valve, and circulation pump through its relays. It enforces the safety times—pre-purge, safety, and lockout—and monitors the flame signal. An electronic control board is matched to the specific boiler model; a board for one Diematic generation or software version is not interchangeable with another. When replacing such a board, the exact model designation and any software revision must be verified against the boiler data plate. A mismatch can cause incorrect timing or prevent the boiler from starting. The board is normally housed inside the boiler control panel and is replaced as a complete unit.