Raypak FFL: False Flame Signal
FFL means the control board is detecting a flame signal at a moment when no burner should be lit at all.
The gas valve should be fully closed right now, and yet the control board is insisting it sees a flame — that contradiction is exactly what FFL reports. It's effectively the opposite problem from an ignition failure: instead of the heater struggling to get a flame going when it wants one, it's picking up a flame-sensing signal when it shouldn't be seeing one at all, which points the diagnosis toward the valve or the sensing circuit rather than the burner or gas supply.
High severityApplies to: Raypak Digital ASME and low-profile residential gas pool/spa heaters
What it means
False flame signal — the control detects a flame signal when the gas valve should be closed and no burner should be lit. Because the flame-sensing circuit is part of how the heater confirms it's safe to open the gas valve at all, a false reading here undermines that whole safety check, which is why Raypak treats it as a hard-stop fault rather than something to clear and retry.
Likely causes
- Pilot or main gas valve stuck slightly open
- A shorted or faulty flame-sensing circuit
What you can check yourself
- Turn off the heater; do not attempt to disassemble or test the gas valve yourself
A false flame signal is a gas-safety fault involving the valve and flame-sensing circuit. Leave the heater off and have a licensed gas technician inspect and test the valve before it's used again.
Sources
Related
- All Raypak error codes
- Raypak ROL — another combustion-safety lockout that shouldn't be reset without inspection
- Raypak IGN — the opposite flame-detection problem: no flame found when one is expected
- Hayward bD — Hayward's gas-valve circuit fault, a similar valve-electronics issue
- Pool Heater Won't Ignite — related startup and combustion troubleshooting