Check High Speed RPM
engine
Description
Control is calling for high speed, but engine speed stayed below 1650 rpm or above 1950 rpm for more than 60 seconds; alarm only.
Activation Conditions
The control system is calling for high speed operation and engine speed is less than 1650 rpm, or greater than 1950 rpm for more than 60 seconds (120 seconds when the control system calls for a change from low to high speed, or when unit first starts).
Unit Behavior
Alarm only.
Reset Conditions
Auto reset if control system is calling for high speed operation and the speed is within 1670 and 1930 rpm for 60 seconds or alarm may be manually reset using the display mounted keys or by turning the unit off, then back on again.
Corrective Actions
1. Force High Speed Operation: Place unit in continuous run, adjust setpoint above 11°F (-12°C) and set the Air Flow Functional Parameter to HIGH. (Reset following testing). System should run in high speed. (If not, check speed overrides, Section 4.11.2.) Ensure System is calling for high speed when performing steps 3 and 4. 2. Check Engine Speed a. Check actual engine speed using hand held tachometer. Refer to Table 2–1. Speed must be within range shown above. b. Compare actual speed with that shown in Unit Data. Readings must be within ± 50 rpm. 3. Check Engine Air Intake System a. Check air cleaner indicator. Flag must not be visible. b. Inspect air intake system. Verify that hoses and tubes are in good condition, with no kinks or restrictions. 4. Check Engine Exhaust System: Inspect the exhaust system. Must be clear and unobstructed.