NTI Boiler: Flame signal too low or flame loss
Flame signal too low or flame loss on a NTI boiler: The control reads the flame signal in parameter 8.7.9. It needs a signal above 18 to detect flame at start, and it calls a flame loss if the signal falls below 15. The gap between those two numbers is your margin. A signal that barely clears 18 and sags during the run is the early warning before the boiler starts locking out.
Applies to: TRX boiler flame detection
Common causes of flame signal too low or flame loss
- Weak or dirty flame sensing, such as a fouled or worn sensor rod
- Low gas supply or incorrect gas setup
- Ignition power set incorrectly (parameter 2.2.0)
- Poor burner condition or bad flame pattern
- Loose or damaged sensor wiring
How to fix flame signal too low or flame loss: step by step
- Open the complete menu and read the flame signal at parameter 8.7.9 while the burner runs.
- Confirm the signal rises above 18 at ignition, since the control will not accept the flame otherwise.
- If the signal drops below 15 during operation, check the flame sensor and burner condition.
- Inspect the sensor rod and clean light deposits, and check its wire and connector for looseness or damage.
- Check that the ignition power in 2.2.0 matches Table 33 for the gas and PCB in use.
- Confirm gas supply pressure and fuel setup match the rating plate, and verify combustion with an analyzer.
- Gas and combustion work belongs to a licensed technician.
If the unit shows an error code, look it up: NTI Boiler codes
Models
TRX085TRX110CTRX150TRX199TRX199C
Source: NTI TRX150 manual, p. 79. 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.