Boiler displays E060 and stops, often with no response to thermostat calls

Safety first: Turn off power before working on low‑voltage thermostat wiring.

• Step 1 – Check thermostat: Ensure the thermostat or room controller is powered, set to heat mode, and calling for heat.
• Step 2 – Inspect wiring at boiler: Verify thermostat wires are securely connected to the correct TT or room controller terminals on the Navien control board.
• Step 3 – Bypass test: Temporarily jumper the TT terminals at the boiler (if allowed by the manual). If the boiler responds, the issue is in the thermostat or its wiring.
• Step 4 – Repair or replace: Repair damaged thermostat wiring or replace the thermostat/room controller as needed.

Remove any test jumpers after diagnosis and restore proper thermostat control.