1+2

Blower on after power up (115VAC or 24VAC). Blower runs 90 seconds if unit powered up during call for heat, or when R-W/W1 opens during blower on-delay period.

This code typically points to

Not a fault; typical triggers are power restoration during active heat call, or loss/opening of heat call during blower on-delay period

Next checks to confirm

Verify whether power was just restored during heat call, or whether R-W/W1 opened during blower on-delay
If yes, treat as normal 90-second blower-only operation

Escalation

No escalation if behavior matches OEM conditions and clears after 90-second interval.

Reset behavior

Self-clearing. After 90-second period, LED returns to heartbeat if no faults detected.

Informational

No action needed