Electronics International US-8A - Manual (Page 17)

Operating Information
A) Selecting the High Oil Limit: On a hot day with your engine set at 75% power, lean your engine
to peak EGT. Record the Oil Temperature reading with the cowl flaps closed. Program the High Limit
for 20’F above the recorded reading.
Some aircraft reach the highest Oil Temperature during a long full throttle climb. If this is the case for
your aircraft, record the highest Oil Temperature reading during a long climb. Program the High Limit
for 20’F above the recorded reading.
This Oil Temperature Limit should not be set higher than the maximum limit allowed for your aircraft.
B) Selecting the Lower Oil Limit: At cold temperatures the viscosity of oil increases. Although
synthetic oils will operate at relatively cold temperatures, most oils will not flow well below 50’F. Set
the Lower Oil Limit to the minimum allowed operating temperature limit for your aircraft.
5. Outside Air Temperature:
The Ultimate Analyzer has two features that make it a valuable tool when measuring outside air tempera-
tures. The first of these features is its superior accuracy and linearity over conventional gauges. Outside air
temperatures have a big affect on your aircraft’s ability to lift and on engine horsepower. Accurate OAT
readings are essential if you are looking for maximum performance from your aircraft.
The second valuable feature is the Ultimate Analyzer’s ability to detect small temperature changes (1’F).
This gives the pilot rate and trend information (in what direction and how fast the temperatures are changing)
at a glance. This is valuable for detecting changing atmospheric conditions and avoiding thunderstorms and
icing conditions. It can also help in warm weather to find cooler flying conditions.
Selecting the Higher and Lower OAT limits: If the Higher or Lower OAT Limits are exceeded, the scan
will stop and the appropriate “Temp Prob” light will come on. For this reason you may want to disable the
Higher and Lower OAT Limits (program them for 000).
6. Carburetor Temperature:
Venturi affect and atomization of fuel can cause temperatures in the carburetor to drop 25’F or more. When
the atmospheric conditions are right, this temperature drop will cause icing in the carburetor. As icing starts
to form, the Ultimate Analyzer will display a temperature near 32’F. To avoid carburetor icing, apply partial
carburetor heat to bring the carb temp between 39’F and 49’F. Outside air temperatures below 10’F will not
cause carb icing due to the lack of moisture in the air.
A) Selecting the High Carb Temp Limit: The High Carb Temp Limit can be used as a fire detector or
detonation deterrent. If the Carb Temp exceeds 150’F for many aircraft the engine can detonate at high
throttle settings.
14
Selecting the Proper Limits