E7
Bryant
Auxiliary Heat / Furnace Communication Fault
Thermostat shows E7 and auxiliary heat or furnace operation is disabled or limited.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Incorrect Bryant furnace or air handler configuration in thermostat, Open or miswired W/W2 or ABCD communication wiring to indoor unit, Failed indoor unit control board, Loose low-voltage connections at furnace control board
How to Fix / Troubleshooting
Safety first: Turn off power to the furnace/air handler at the service switch and breaker.
Steps to troubleshoot:
- 1. Confirm equipment configuration: In the thermostat installer menu, verify that the indoor unit type (gas furnace, fan coil, stages) matches the actual Bryant equipment.
- 2. Inspect low-voltage wiring: At the furnace/air handler, check that the thermostat cable is properly connected to the Bryant control board terminals (ABCD for communicating systems, or R, C, W/W2 for non-communicating). Tighten any loose screws.
- 3. Look for damage: Inspect the thermostat cable for cuts, burns, or rodent damage. Replace damaged sections with new thermostat wire.
- 4. Power cycle: After corrections, turn power off for a few minutes, then restore and see if E7 clears.
- 5. Professional diagnosis: If E7 remains, the indoor control board or thermostat may have a communication fault that requires Bryant service tools to diagnose.
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Repair Difficulty
Medium
3/5
Required Part
Bryant Furnace/Air Handler Control Board
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