Trane Furnace Code E7.2
Safety fault
The redundant safety relay on the control (HLO output) is energized when it should not be.
Manual wording: “Redundant Relay (HLO output) Energized when it should NOT be”
Documented for: S8V2 and S9V2-VS furnaces
Likely causes, most common first
- Redundant relay (HLO output) energized when it should NOT be
- Control board relay fault
When to call a technician
Call a technician. The redundant relay is part of the gas-valve safety chain and a stuck relay means the board must be replaced.
A Trane furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation, Operation, and Maintenance - Gas-Fired 2-Stage Condensing Variable Speed Furnaces with Variable Speed Draft Inducer (FNR-SVX001B-EN) (Trane, S9V2B040U3VSBB through S9V2D120D5VSBB (S9V2-VS) two-stage condensing variable-speed furnaces) · checked 2026-08-25
- Installation, Operation, and Maintenance - Link Communicating or 24 Volt Gas-Fired 2 Stage Induced Draft Furnaces with Variable Speed Motor (FNR-SVX003A-EN) (Trane, S8V2A040M3PCB through S8V2D120M5PCB two-stage 80% induced draft furnaces (communicating or 24V)) · checked 2026-08-25