On the covered Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace, E2.1 means retry exceeded: flame was never sensed. The furnace locks out for one hour after 3 tries. First, check that the gas supply valve to the furnace is open and that other gas appliances are working.
Differential
Likely causes of “Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace showing E2.1”, and how to tell them apart
- 1
Flame never sensed
What separates it Three tries then a one-hour lockout
How to confirm Technician ignition check
- 2
The gas supply valve is closed
What separates it No gas reaches the burners
How to confirm Open the valve to the furnace
- 3
A dirty flame sensor
What separates it Ignition then no proof of flame
How to confirm Technician cleaning
- 4
A weak igniter
What separates it The igniter glows dull
How to confirm Technician replacement
- 5
Other gas appliances also fail
What separates it A supply problem
How to confirm Call the gas utility
Before you touch a setting
Record this first — changing settings destroys the evidence
- That the display shows E2.1
- Whether the gas valve is open
- Whether other gas appliances work
- Whether the igniter glows
Try in this order
0 of 8 completedWhat to do first
ReversibleCheck that the gas supply valve to the furnace is open and that other gas appliances are working.
Correct only the documented fault domain
ReversibleIgnition, gas and flame-sensing checks belong to a technician.
Check the gas valve to the furnace
ReversibleThe handle should be in line with the pipe.
Test another gas appliance
ReversibleFor supply.
Wait out the lockout
ReversibleOne hour.
Watch one start
ReversibleFrom a safe distance.
Note the result
ReversibleIgniter, flame.
Call a technician
ReversibleFor ignition and flame sensing.
Model-specific
What is true of this model and not of its siblings
- Three tries
- The control tries to light the burners three times. If it never senses flame, it stops for an hour.
- Trane's guidance
- Check the gas supply valve and other gas appliances; ignition, gas and flame-sensing checks belong to a technician.
- The igniter
- A hot surface igniter glows orange. A dull or absent glow suggests it has failed.
- The flame sensor
- A rod that proves flame.
- Seasonal start-up
- After months of idle, the first start of the year can show this code if the gas line has air or the sensor is dirty.
- Gas utility
- If other appliances fail too, call the utility.
- The igniter and the sensor
- The S9V2 lights its burners with a hot surface igniter, a small element that glows. Once the gas lights, a flame sensor proves it. If the igniter does not glow, a different code or a different symptom appears. E2.1 means the control tried, opened the gas and never sensed flame.
- Check the simple things
- Make sure the furnace's gas valve handle is parallel to the pipe, which means open. If other gas appliances, such as a stove or water heater, work, the supply to the house is fine. If they do not, call the utility.
- What a technician checks
- Gas pressure at the valve, the igniter's glow and resistance, the flame sensor's condition and the grounding of the furnace. Poor grounding can stop a flame sensor from reading, so ask whether it was tested.
- What three tries look like
- On a call for heat you hear the inducer start, then a pause, then a click as the gas valve opens. The igniter glows and the burners should light within seconds. If they do not light or the flame is not sensed, the control repeats the sequence twice more and then stops. You may hear the pattern three times in a row, followed by silence.
- Intermittent starts
- A furnace that lights on some tries and not others may have a weak igniter, a draft problem or a dirty sensor. Note whether the furnace lit at all before the code, since a furnace that lit and ran for years suggests wear while one that has never lit points to an installation issue.
Stop boundary
When this stops being a self-service repair
- !Never bypass, jumper or tape over a safety switch
- !Stop for a carbon monoxide alarm, soot, scorch marks or flame outside the burner compartment
- !Call a qualified technician for anything behind the furnace's panels
- !If you smell gas, leave the building and call the gas utility from outside; do not use switches or phones inside
Evidence ledger
Sources behind this answer
Exact questions
Common questions
What does E2.1 mean on a Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace?+
Retry exceeded: flame was never sensed. The furnace locks out for one hour after 3 tries.
How long is the lockout?+
One hour after three tries.
What can I check?+
That the gas valve is open and other appliances work.
Who does the rest?+
A technician.