EC120B Hydraulic Troubleshooting

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The following are some steps to take when you have no hydraulics and the hydraulic light is on.

SYMPTOM:
PILOTE REPORTS NO HYDRAULIC ASSIST TO FLIGHT CONTROLS AND HYDRAULIC LIGHT IS ON.


TROUBLESHOOTING:
1. FIRST DETURMINE IF THE FAILURE IS DUE TO ELECTRICAL OR MECHANICAL PROBLEM.

2. PREFORM GROUND RUN, LOOK AT SIGHT GLASS ON HYD PACK, HYD FLUID SHOULD BE CIRCULATING.
a. IF FLUID IS CIRCULATING: ELECTRICAL PROBLEM.
b. IF FLUID IS NOT CIRCULATING: MECHANICAL PROBLEM.

ELECTRICAL: Ref: WDM 29-11-00-001 & 29-31-00-001

“ELECTRIC VALVE”

1.CHECK B6, 3 AMP CIRCUIT BREAKER, ON CARGO CIRCUIT BREAKER PANEL.

2. CHECK FOR 28 VOLTS AT PIN 2, WITH HYD SWITCH IN THE ON POSITION. AT THE ELECTRICAL VALVE LOCATED ON THE HYD PACK.

3. CHECK GROUND FROM ELE VALVE PIN 1.

NOTE: ELECTRIC VALVE CAN BE SWAPPED WITH SERVO ELE. VALVE FOR TROUBLESHOOTING “SAME PART NUMBER”

“PRESSURE WARNING”

1. CHECK FOR 28 VOLTS AT PIN 1, ON HYD PRESSURE SWITCH.

2. CHECK GROUND FROM PRESS SWITCH PIN 3.



MECHANICAL:

1. CHECK SPLINE DRIVE BETWEEN HYD PACK AND MGB.

2.BROKEN ROLL PIN ON MUFF COUPLING.

3. WORN SPLINES ON HYD PACK OR MGB.

4. CHECK ROTATION OF HYD DRIVE SHAFT IN MGB.

More troubleshooting at http://www.heliwrench.com