No model data. This is a critical fault. The furnace will not operate in any mode, including a thermostat call.
Likely causes
- Memory card missing from the furnace control, or disconnected from connector P6
- Furnace control replaced without the original memory card installed in the replacement
Safe checks for d1
- Write down d1. The manual says a missing card shows d4 instead when model data is already on the network
- Technicianinstall the original memory card in connector P6. If it cannot be found, the manual says a replacement is ordered from ProStock for that furnace model. Power must be cycled off and on after the card is installed or the data will not be read
- Techniciando not install a memory card from another furnace or from a condenser or air handler. The manual says the wrong card can damage the heat exchanger
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician. d1 means the furnace has no model data and will not run.
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Parts & tools for this fix
Taken from this code's causes or steps. A search link opens Amazon results and does not confirm a fit. Check the model number in the manual.
Furnace control board and low-voltage fuse: guide
In this code: Parts list for this code: Integrated furnace control
This one is for a technician to test or replace, so we only explain it and do not link to buy it.