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Service Manual
Adjustments
Checking switch continuity
38
Series 90 Pumps
C
Caution
Do not turn the eccentric plug into or out of the housing beyond specifications.
7. Once the switch is correctly adjusted, hold the switch in place and tighten the lock nut to 27 N•m [20
lbf•ft] torque.
NSS deadband adjustment (conditions ii & iii)
The NSS deadband must be wide enough so the NSS will not open within the control shaft free-play area,
and it must be narrow enough so the NSS will open before the unit builds 7 bar (100 psi) differential
system pressure in either direction.
1. Install two 1000 bar [10 000 psi] pressure gauges in the system pressure gauge ports M1 and M2.
2. Using two 1-1/8 inch wrenches, hold the neutral start switch from turning and loosen the lock nut.
3. Disconnect the external control linkage and make certain the control shaft is in its neutral position.
4. Attach a continuity checker to the terminals of the switch. With the control shaft in its neutral
position, turn the switch clockwise (CW) until the switch opens, then turn the switch
counterclockwise (CCW) until it closes. Turn the switch counterclockwise (CCW) an additional 1/4 turn
(90°) after the switch closes.
5. Hold the switch in place and tighten the lock nut to 27 N•m (20 lbf•ft) torque.
6. With the continuity checker attached to the switch, rotate the control handle (or the control shaft) in
each direction to assure the switch opens when the control is not in the neutral position.
7. If the switch closes in neutral and satisfactorily opens in each direction, proceed to check the switch
with the prime mover running. The switch must open before the unit builds 7 bar [100 psi] differential
system pressure in either direction.
If the switch opens after the unit builds system pressure in either direction, loosen the switch lock nut
and turn the switch clockwise (CW) 1/12 turn (30°). Tighten the switch lock nut and recheck the switch
operation. Repeat this procedure if necessary.
8. If the switch does not open with an equal movement of the control handle in each direction, turn off
prime mover, remove the pressure gauges, and continue with the next section.
9. If neutral start switch operation is satisfactory, turn off the prime mover, remove the pressure gauges,
and reconnect the external control linkage.
Neutral start switch
Control shaft
Switch cam
Switch pin
1-1/8 in
27 N•m (20 lbf•ft)
Recheck switch continuity to determine whether additional adjustment of the eccentric plug is necessary.
520L0818 • Rev 0101 • August 2015
Switch lock nut
Neutral start switch
P104 148E
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