He then found the NIMS installation with a geothermal heat pump. “The infinity” geothermal heat pump is what he was told by the homeowner. But in reality, it was a geothermal heat pump communicating by use of the NIMS installation

He was ohming out the NIMS module. We suggested that he try running new thermostat wire, or using 2 extra wires in the bundle not being used. Once he made the changes to the wires on the NIMS and the indoor infinity furnace, guess what. The code 179 went away. The geothermal heat pump then began operating. Communication was established. So thus, it was not communicating with the older thermostat wires, but operated and communicated with the indoor infinity furnace and UI with the newer thermostat wires.

So, the NIMs installations is definitely a tool all techs could use if needed on certain installations. The Network Interface Module (NIM) is used to interface the following devices to the Infinity ABCD bus so they can be controlled by the Infinity System. The following devices do not have communication ability and the NIM is required to control: • A Heat Recovery Ventilator / Energy Recovery Ventilator (HRV/ERV) (when zoning is not applied). • A non-communicating single-speed heat pump with Infinity furnace (dual fuel application only). • A non-communicating two-speed outdoor unit (R-22 Series-A unit)

More information on the NIMS can be found in HVAC Partners, or on your Carrier or Bryant service app.