Geo Unstable Internal Power or Firmware Crash

Thermostat reboots randomly several times a day without user interaction.

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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 R or C connection at wall plate, Marginal 24 VAC transformer, Firmware bug causing watchdog resets, Overheating of internal regulator on Geo PCB

How to Fix / Troubleshooting

Safety first: Turn off HVAC power at the breaker before inspecting wiring.

  • Step 1 – Check R and C terminals: Remove the thermostat and ensure R and C wires are fully inserted and clamped. Tighten any loose screws.
  • Step 2 – Measure voltage: With power on, measure between R and C at the wall plate. Voltage should be stable around 24 VAC and not drop significantly when the system starts.
  • Step 3 – Improve ventilation: Ensure the thermostat is not in a hot, enclosed space and that its vents are not blocked.
  • Step 4 – Firmware update and reset: Update firmware via the Geo app and perform a factory reset if reboots continue.
  • Step 5 – Replace thermostat or transformer: If voltage is unstable, have an HVAC technician evaluate the transformer. If voltage is stable but reboots persist, replace the thermostat head unit.
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Repair Difficulty

Medium 3/5

Required Part

Internal Power Supply Circuit / Main Control PCB
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