Trane Error Code E4.2: Flame rollout switch open (Furnace)
Trane error code E4.2 on a furnace means: Flame rollout switch open. It is also called Trane diagnostic code E4.2.
Homeowner? What Trane code E4.2 means for you
Stop and call Your furnace is reporting: Flame rollout switch open. This code is a safety shutdown. Turn the furnace off and call a licensed technician. Do not keep resetting it. If you smell gas, leave the house and call your gas utility or 911 from outside.
Safe things you can check yourself
- Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
- Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Trane error code E4.2 mean?
A rollout switch on the burner box tripped, meaning flame escaped the heat exchanger inlet. Treat as a combustion/venting safety issue.
Applies to: Trane S8V2 only
Common causes of Trane code E4.2
- Wrong orifices (natural gas drill 45; LP drill 56 or per guide)
- Vent undersized, poorly pitched or blocked
- Burners dirty or misaligned
A technician checks these and 2 other possible causes on site before replacing any part.
Trane models that use code E4.2
S8V2A040M3PCBS8V2A040M3PDS8V2B060M4PCBS8V2B060M4PDS8V2B080M4PCBS8V2B080M4PDS8V2C080M5PCBS8V2C080M5PDS8V2C100M5PCBS8V2C100M5PDS8V2D120M5PCBS8V2D120M5PD
Other Trane Furnace codes
All Trane Furnace error codes →
Trane code E4.2: homeowner questions
What does Trane code E4.2 mean?
Flame rollout switch open. A rollout switch on the burner box tripped, meaning flame escaped the heat exchanger inlet. Treat as a combustion/venting safety issue.
Is it safe to keep using my furnace with code E4.2?
No. Code E4.2 is a safety shutdown, so keep the furnace off until a licensed technician has checked it.
Can I reset Trane code E4.2 myself?
Do not keep resetting it. Repeated resets can hide a safety problem; a licensed technician needs to find the cause.
Who can fix Trane code E4.2 near me?
Aurora Star Tech Inc. repairs Trane furnaces in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean
Troubleshooting guides
- Blowing cold air All brands · Furnace
- No heat All brands · Furnace
- Short cycling All brands · Furnace
- Reading and clearing fault history - Trane S-Series IFC Trane · Furnace
Source: Trane FNR-SVX003A-EN (S8V2 installer's guide) - section Integrated Furnace Control Display Codes, Table 37 Error codes; Trane FNR-SVX003A-EN (S8V2 installer's guide) - section Troubleshooting (flowcharts). Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.