What this code means
The American Standard S9V2 furnace service manual identifies E01 as internal furnace-control failure.
Safe checks
- Confirm the thermostat is on, set correctly, and calling for heating or cooling.
- Check the air filter and visible return-air path for obvious airflow restrictions.
- Record the displayed code or flash sequence before scheduling service.
First step
Record the code, avoid repeated reset attempts, and schedule GreenFlow service.
Frequently asked questions
What does E01 mean on a American Standard S9V2B040D3PSC?
The American Standard S9V2 furnace service manual identifies E01 as internal furnace-control failure.
What should I safely check before scheduling service?
Use only the visible, non-invasive checks listed on this page. Do not open equipment panels.
When should GreenFlow handle this code?
Call GreenFlow if the code repeats, the equipment is locked out, heating or cooling is not restored, or the condition involves gas, ignition, pressure, wiring, a motor, or a control board.