Johnson Controls Excessive Internal Heat Generation

Thermostat plastic housing feels unusually warm to the touch during normal operation.

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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

High ambient temperature at wall, Overloaded internal power supply due to accessories, Faulty voltage regulator on PCB, Thermostat mounted over warm duct or pipe

How to Fix / Troubleshooting

Safety: Turn off power before removing the thermostat from the wall.

  • Step 1 – Check environment: Ensure the thermostat is not installed above a heat source or in direct sunlight.
  • Step 2 – Inspect behind wall: Remove the thermostat and feel for warm air or hot pipes behind the wall. Add insulation or relocate the thermostat if necessary.
  • Step 3 – Reduce accessory load: If multiple devices are powered through the thermostat, move them to a separate transformer.
  • Step 4 – Monitor operation: Mild warmth can be normal, but if the thermostat is hot and performance is erratic, replace the thermostat to avoid failure.
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Repair Difficulty

Medium 3/5

Required Part

Thermostat Assembly (Internal Regulator)
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