Honeywell TH5220D1003 manual

Everyday control

Choose the system mode, then the temperature

1. Press the button below System until Heat, Cool or another available mode is shown.
2. Use the temperature buttons to change the preferred setting. Compare the Setting temperature with Inside, the measured room temperature.

This is a non-programmable thermostat. A changed temperature is not a temporary schedule override, and there is no weekly program to restore with a Run button.

Heat asks for heating; Cool asks for cooling. Em Heat is available only on appropriately configured heat-pump installations and locks out the compressor. Do not select it as a general troubleshooting shortcut.

Two different Auto settings

System Auto and Fan Auto do different jobs

With System Auto, the thermostat can select heating or cooling from room conditions. The manual requires the heat and cool setpoints to stay at least three degrees apart. This deadband is not a fault when a setting moves to maintain separation.

With Fan Auto, blower operation follows heating/cooling calls. Fan On requests continuous fan operation. The System Auto option may be absent, depending on installation settings. Do not change installer settings just to imitate another screen.

Battery holder

Press and pull the battery holder out

1. Have fresh AA alkaline batteries ready. Press down on the battery-holder release and pull the holder out.
2. Replace the batteries following the holder’s + and − marks, then reinstall the holder.
3. Check the display and intended system/fan modes. If it is still blank, use the model’s troubleshooting section rather than a generic reset.

The manual says batteries are optional backup when the thermostat is powered by AC wiring. Its settings are stored permanently; removing batteries is not a reset method.

The model/date-code information is accessible after removing the battery holder. Use the holder for routine battery access instead of prying the whole thermostat from the wall.

Display and response

Allow the compressor restart delay to finish

The manual describes flashing Cool On, or Heat On for a heat pump, during compressor protection. Its troubleshooting guidance says to wait five minutes for response.

If the equipment still does not respond, check that the mode and setpoint request the operation you expect. Persistent no-heating/no-cooling needs the equipment instructions or service. The thermostat message alone does not identify a failed part.

Model match

Confirm the entire TH5220D1003 number

Read the full model on your paperwork or behind the battery holder. TH5220D1003 is in the FocusPRO non-programmable family; do not apply T6 Pro programming, N100 alert-clearing or generic factory-reset instructions.