F15
Ideal
Low Temperature Rise / Inadequate Heating
Furnace displays F15, blower may run but burner does not light, or unit cycles without heating
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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
Oversized blower speed, undersized gas input, partially closed gas cock, dirty heat exchanger reducing transfer, incorrect thermostat anticipator or settings
How to Fix / Troubleshooting
Safety: Gas and airflow adjustments should be made by qualified personnel. User checks are limited to airflow restrictions and thermostat settings.
Steps:
- Check filter and vents: Ensure the air filter is clean and all supply/return vents are open. Restricted airflow can cause abnormal temperature readings.
- Thermostat settings: Verify that any advanced thermostat settings (cycle rate, temperature swing) are appropriate for a gas furnace.
- Observe run time: If the furnace starts and stops frequently without reaching setpoint, note the pattern and provide this information to a technician.
- Professional service: A technician should measure temperature rise across the Ideal furnace, adjust blower speed if necessary, and verify correct gas input.
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Repair Difficulty
Hard
4/5
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