- The SRL8 uses a heated diode sensor. The heated diode’s advantage is that it detects absolute concentration levels so it can be held on a leak and will continue to beep. It is also initially very sensitive. Its major disadvantages are that the sensor becomes less sensitive over life, eventually needing replacement and it is more sensitive to some refrigerants than others.
- The SRL2 uses an infrared (IR) sensor. It detects a CHANGE in concentration, so the wand must keep moving. The main advantages of the Fieldpiece IR sensor are that its sensitivity will remain the same over the life of the instrument, the sensor will last the lifetime of the instrument, it will not trigger on humidity or on oil, and it has nearly the same sensitivity to most refrigerants. The main disadvantage of infrared sensors is their sensitivity to mechanical disturbances.
