Payne PG96VTA Error Code 25: Invalid Model Selection or Setup Error
What Does Code 25 Mean?
Code 25 (two short flashes followed by five long flashes) is a setup/configuration message rather than a component failure, which is why its severity is low. Its meaning depends on how it flashes. If code 25 flashes only 4 times at power-up, the control simply did not find a model plug and is defaulting to the model selection stored in its memory — the furnace can still run.
If code 25 flashes continuously, the control cannot resolve a valid configuration. Common reasons are a missing or incorrect model plug (PL4), or setup switches SW1-1 or SW1-6 positioned improperly. A service/replacement board with no valid model stored in permanent memory needs the PL4 model plug installed.
Less common causes are a thermostat call with SW1-1 and SW1-6 both ON together, or two different furnace models twinned with an incompatible configuration (which needs a compatible twinning board and control software V17 or later). Because it centers on the model plug and DIP-switch setup — technician-configured items — code 25 is verified by a professional, typically right after a control-board swap.
What You'll Notice
- The amber LED flashes code 25 (two short flashes followed by five long flashes)
- A brief 4-flash burst of code 25 only at power-up, after which the furnace runs normally on stored settings
- Continuous code 25 flashing with the furnace failing to operate correctly
- The condition typically appears right after a control board was replaced or serviced
- In twinned installations, the code appears when two units are configured incompatibly
Common Causes
How This Is Diagnosed
A technician first distinguishes the harmless 4-flash-at-power-up case from continuous flashing. For continuous code 25, they verify the correct model plug (PL4) is installed on the board and that setup switches SW1-1 and SW1-6 match the furnace model and installation, referencing the setup label.
For twinned systems, they confirm both furnaces are compatible and running the required control software version. This is board-configuration work using the manufacturer's setup instructions and is not a homeowner task, though it is a setup issue rather than a safety failure.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- Code 25 flashes continuously and the furnace does not operate correctly
- The code appeared right after a control board was replaced (the model plug PL4 may be missing)
- The furnace is twinned with another unit and the configuration may be incompatible
- You are unsure whether setup switches SW1-1 and SW1-6 are set correctly for this model
Frequently Asked Questions
Is code 25 on my Payne PG96VTA serious?
Usually not. If it flashes just 4 times at power-up, the control is using stored settings and the furnace can run. Continuous flashing means the model plug or setup switches need correcting, typically after a board replacement.
Why did code 25 appear after my control board was replaced?
A new or service board needs the model plug (PL4) installed and the setup switches set for your furnace. Without a valid stored model it flags code 25. A technician configures the replacement board.
What is the PL4 model plug?
PL4 is a small plug that tells the control which furnace model it is installed in. If it is missing or incorrect, the control cannot select the right operating parameters and flags code 25.
✓ Verified against manufacturer service manual — March 2026