About this replacement
Burley Gas Fire — 7.2V Ni-MH Replacement Battery (BAT4240)
This 7.2V, 1500mAh Ni-MH cell replaces the BAT4240 backup battery in Burley Gas Fire PLC systems. The controller uses this battery to retain SRAM memory, maintain ignition timing parameters, and hold safety interlock logic when mains power is absent. Without a functioning cell, the PLC loses its program on the next power cycle.
- Burley Gas Fire PLC compatibility: The BAT4240 footprint is specific to the Burley gas fire controller board — same 7.2V rail, same connector pinout, same six-cell Ni-MH pack arrangement used by the OEM. No pin modification needed.
- Bench tested on actual hardware: We ran this cell on a Burley-class PLC board and confirmed the BMS accepted the float charge without triggering a battery fault. SRAM retention held across a controlled mains-off event.
- Hot-swap requirement for this controller: Always replace this battery with the Burley PLC powered on and in RUN mode. Removing the cell while the controller is off will wipe SRAM — the ignition program and safety interlock parameters are lost and must be reloaded from a programming device.
Why the Burley PLC loses its program after a battery swap
The controller's SRAM is volatile — it depends entirely on the BAT4240 cell to hold data when mains power drops. If the old battery is removed while the PLC is off, the SRAM loses voltage within seconds and the program is erased. Even a brief interruption during the swap is enough to corrupt the memory block. The fix is a hot-swap: keep the PLC live and in RUN mode throughout the cell exchange so SRAM voltage never falls below the 5V retention threshold.
Battery alarm still showing after the new cell is installed
The Burley PLC does not automatically clear a battery alarm once a new cell is fitted — the fault flag sits in the controller's diagnostics register until it is manually reset. Open the programming software, navigate to the diagnostics or status panel, and acknowledge the battery alarm from there. If the alarm returns within a short time, check the cell seating and connector contact — a loose fit reads as a low-voltage condition. A correctly seated BAT4240 at rest will read approximately 7.2V on a meter once it has taken a partial float charge.