Ruud
No Cool Call from Thermostat
Thermostat has power but will not turn on cooling when temperature is set lower than room temperature
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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
Loose or broken Y/Y1 wire at thermostat or Ruud control board, Incorrect system configuration (set to heat-only), Blown low-voltage fuse from previous short on cooling circuit, Failed cooling call relay/triac on thermostat PCB
How to Fix / Troubleshooting
Safety: Turn OFF power to indoor and outdoor units before accessing wiring.
- Verify mode and setpoint: Ensure the thermostat is in COOL mode and the setpoint is several degrees below the room temperature.
- Check Y/Y1 wiring: At the thermostat, confirm the Y or Y1 terminal has a secure wire. At the Ruud indoor control board, verify the same wire is on the Y/Y1 terminal and that the Y wire to the outdoor unit contactor is intact.
- Fuse inspection: Check the low-voltage fuse on the indoor control board and replace if blown. Investigate for shorts in the Y circuit if it blows again.
- Bypass test (advanced): With power ON and blower door switch closed, briefly jumper R to Y/Y1 at the indoor control board. If the outdoor unit and indoor blower start, the thermostat or its wiring is at fault. Remove jumper after test.
- Thermostat replacement: If the system cools with an R–Y jumper but not via the thermostat, replace the thermostat.
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Repair Difficulty
Medium
3/5
Required Part
Ruud EcoNet Smart Thermostat Assembly
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