Heated diode refrigerant leak detector has three levels of sensitivity to help find leaks as small as 0.25 oz/yr (7 g/yr). The compact detector uses a gooseneck probe to access leaks in tight locations and cramped compartments while also extending access to overhead refrigerant lines. A built-in LED worklight on the probe tip illuminates dimly lit locations. The heated sensor has a fast warmup cycle and quickly detects R22, R134a, R404a, R410a and all CFCs, HCFCs and HFCs. The progressive-color-coded 9-LED bar-graph provides at-a-glance information on levels being detected.