Trane Error Code E27: Return air thermistor out of range or not connected (Furnace)
Trane error code E27 on a furnace means: Return air thermistor out of range or not connected. It is also called Trane diagnostic code E27.
Homeowner? What Trane code E27 means for you
Usually minor Your furnace is reporting: Return air thermistor out of range or not connected. This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.
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.
- Make sure the furnace front door or panel is closed properly; many furnaces will not run with the door switch open.
- Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
- Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
- Check that the gas valve next to the furnace is open (handle in line with the pipe). Do not force it.
- Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Trane error code E27 mean?
The return temperature sensor in the blower harness is open/shorted or enabled but not connected. Furnace still runs.
Applies to: Trane S8V2 only
Common causes of Trane code E27
- Open or shorted thermistor
- Harness damage
- IFC input fault
Trane models that use code E27
S8V2A040M3PCBS8V2A040M3PDS8V2B060M4PCBS8V2B060M4PDS8V2B080M4PCBS8V2B080M4PDS8V2C080M5PCBS8V2C080M5PDS8V2C100M5PCBS8V2C100M5PDS8V2D120M5PCBS8V2D120M5PD
Other Trane Furnace codes
All Trane Furnace error codes →
Trane code E27: homeowner questions
What does Trane code E27 mean?
Return air thermistor out of range or not connected. The return temperature sensor in the blower harness is open/shorted or enabled but not connected. Furnace still runs.
Is it safe to keep using my furnace with code E27?
Usually yes. Code E27 is normally minor, but if it keeps coming back have it checked.
Can I reset Trane code E27 myself?
You can try one reset (power off for 30 seconds, then on). If Trane code E27 comes back, the cause is still there and a licensed technician should check it.
Who can fix Trane code E27 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.