7 components coveredField manual · Thermostat
Carrier Infinity System Control / Infinity Touch and Bryant Evolution Connex communicating wall controls: quick sheet
Covers: Carrier Infinity System Control / Infinity Touch (SYSTXCCITC01 series), older Carrier Infinity Control (SYSTXCCUID01 series) and Bryant Evolution Connex (SYSTXBBECC01 series). Works only with Carrier Infinity / Bryant Evolution communicating equipment.
These are not ordinary thermostats: they are the system controller for a communicating Carrier/Bryant system. Four wires (A, B, C, D) carry both 24 V power and digital data between the wall control, the furnace or fan coil, the outdoor unit and accessories such as zone dampers. There is no W, Y or G call to jumper. Most service calls are wiring/communication faults, a blank control after a short on the bus, or setup changes made in the installer menus.
Safety first
- Do not connect a conventional 24 V thermostat's W/Y/G logic to ABCD terminals
- Power off before changing bus wiring
- Outdoor unit control box has line voltage and capacitors: CAUTION
- Refrigerant faults reported by the outdoor unit are BLOCKED: refer to an EPA 608-certified technician
How it works
A and B carry RS-485 serial data; C and D carry 24 VAC from the indoor unit's transformer. Carrier's product data gives the color convention A green (data +), B yellow (data -), C white (24 V common), D red (24 V hot), but always follow the actual labels at each terminal.
Each device on the bus is discovered by the control at power-up. If the indoor or outdoor unit cannot be found, the control shows a 'not found' or communication message instead of running.
Zoning (up to eight zones with the Infinity zoning panel), humidity, ventilation and airflow are all managed from the wall control. Carrier lists compatibility with Greenspeed and Hybrid Heat (dual fuel).
Carrier's trade guidance is that most communication faults come from the field wiring, not from boards; isolate devices one at a time before replacing parts.
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