Error 76 appears on the Richmond tankless display; remote controller may not respond.

Safety first: Turn OFF power before working on low-voltage wiring.

• Check cable connections: Inspect the communication cable between the heater and the remote controller. Ensure both ends are firmly connected and not corroded.
• Inspect cable for damage: Look for staples through the cable, cuts, or crushed sections. Replace the cable if damaged.
• Verify polarity: Many Richmond remotes require correct polarity on the two communication wires. Confirm that terminals + and - are matched at both ends.
• Test with short cable: Temporarily connect the remote to the heater with a short, known-good cable near the unit. If error 76 clears, the in-wall cable is faulty.
• Replace remote: If wiring is good but communication still fails, the remote controller or main board communication circuit may need replacement.