Auxiliary Adaptor Board

For most indoor units where this adaptor board is compatible, the following 3 sequences are available: 1. Simultaneous : when the indoor unit is in heating mode, the adaptor board closes a set of dry contacts to engage auxiliary heat. The indoor unit remains in heating mode. 2. Second Stage : when the indoor unit is in heating mode, and if the space temperature falls 3.5°C (adjustable, for most indoor units, to certain presets) below the heating set point, the adaptor board closes a set of dry contacts to engage auxiliary heat. The indoor unit remains in heating mode. 3. Dual Fuel Optimization : the Second Stage sequence is used until the outside air temperature drops below a certain value (adjustable at the outdoor unit). Below this value, heat pump heating is disabled, and the adaptor board engages and controls auxiliary heat with a 1°F deadband. The transition temperature allows for optimization of operating costs.

The new FXSQ_TBVJU, FXMQ_TBVJU, FXZQ_TBVJU, FBQ_TBVJU, and FCQ_TBVJU units have each undergone changes from the previous generation of models. Among these changes is a new connector design to the X33A plug which is no longer compatible with the wiring harness that ships with the KRP1C74 and KRP1C75 boards. When connecting the adaptor to one of these new units, the old harness must be removed and replaced with the special harness. See the Wiring Harness Technical Service Bulletin from Daikin for more information, such as a compatibility and pairing chart.