Danfoss S40 P Installation guide

Brand: Danfoss

Model: S40 P

Type: Installation guide

Danfoss S40 P is a neutral start switch designed to prevent the start of the prime mover when the pump is not in neutral. It features a special alignment tool for precise installation, ensuring proper functionality and safety. The S40 P is compatible with Sauer-Danfoss M46 pumps and can be easily integrated into existing systems. With its durable construction and reliable performance, the Danfoss S40 P offers peace of mind and enhances the safety of your pump operations.

Hex: 0.5"

Note Orientation

Reuse Original Part

Do Not Reuse

Do Not Remove

Hex: 0.25"

Torque to 6-8 Nm (8-11 lbf•ft)

1254

1253

1252

Fig. 2 -- Remove Control Spool

Fig. 3 -- Install Mounting Plate

Make sure prime mover (engine) is off.

Remove Old Control Spool (Fig. 2):

1. Note the position of the control handle and neutral

bracket. Control handle orientation should remain

the same after NSS installation.

2. Using a 7/16" or 3/8" wrench to remove the control

bracket hold down bolt. Slide the control spool/

handle assembly out of the unit.

3. Remove the control handle nut from the old control

spool with a 1/2 inch wrench.

4. Remove the old control spool from the control

handle, neutral bracket, and spring.

The control spool and its backup ring and O-ring

are the only parts that must be changed out. It is

not necessary to remove the control sleeve.

Install Mounting Plate (Fig. 3):

5. Install the mounting plate gasket (1252) and mount-

ing plate (1253), using the three 1/4-20 x 0.500 hex

head screws (1254) and torque to 6-8 Nm (8-11

lbf•ft).

Note: Be sure the gasket is correctly oriented and

does not block any mounting plate passages.

Control Spool Assembly (Fig. 4):

6. Place the backup ring (1209) and O-ring (303) on

the control spool assembly (1207) as shown (may

be preassembled).

7. Place the cam (1247) on the spool assembly and

install the 1/4 inch washer (1248) and 1/4–20 x 0.5

socket head screw (1249) into the cam locking

bracket (1246). Finger tighten and back off 1/4

turn.

0.40

1.25

1.8

9/16-18

UNF-2A Thd

0.182

Fig. 1 -- Special Alignment Tool

Procedure

The neutral start switch is designed to prevent the start

of the prime mover when the pump is not in neutral.

Sauer-Danfoss publication BLN-9939 (M46 Service

Manual) should be at hand as reference.

Figure 1 illustrates a special alignment tool to be used

in step 13. Dimensions are included for fabrication.

Piece parts should not be mixed from one kit to another due to possible incompatibility between kits

Service Kit Instructions

Series 40 - M46

Neutral start switch installation instructions

Note orientation

for reuse

1258

1251

Control Spool Assembly

1255

1256

1257

1236

Hex: 0.5"

Torque to 7-9 Nm

(10-23 lbf•ft)

Hex: 0.375"

Torque to 6-8 Nm

(8-11 lbf•ft)

Hex: 0.875"

Torque to 9-10 Nm

(12-14 lbf•ft)

(1249)

Note Orientation,

Re-install as Before

Internal Hex: 0.25"

Torque to 11-15 Nm

(8-11 lbf•ft)

Internal Hex: 0.25"

Do not torque

initially

1249

1248

1247

1250

1246

1207

1209

303

Lubricate

Fig. 4 -- Control Spool Assembly

Fig. 5 -- Control Handle Assembly

Fig. 6 -- Cover Assembly

8. Install O-ring (1250) on to the spool assembly.

9. Lubricate the O-rings, outside cam face, and corre-

sponding surface of the NSS cover with assembly

grease.

Control Handle Assembly (Fig. 5):

10. Fit the control handle and neutral bracket between

the ends of the spring.

Neutral Start Switch Cover Assembly (Fig. 6):

11. Place the control spool assembly in the neutral

start switch cover (1251). Put the spacer (1258)

over the spool.

12. Secure control handle assembly on the new spool

with the old nut. Torque to 7-9 Nm (10-12 lbf•ft).

Note: Make sure the control handle is in the correct

position for your application.

13. Visually align the notch in the cam (1247) with the

hole in the NSS cover (1251). Insert special align-

ment tool (Fig. 1) to hold the cam in position.

Finger tighten only.

14. Place neutral start cover gasket (1255) on the

mounting plate.

15. Place the neutral start cover assembly on to the

control sleeve and pump housing.

16. Attach the neutral start switch cover assembly on

the pump using the two 1/4–20 x 5/8 screws (1256)

and torque to 6-8 Nm (8-11 lbf•ft).

Note: It may be necessary to loosen and retorque

the bolts to prevent binding of the control handle.

Final Adjustments:

17. Set neutral on the control handle

using the proce-

dure outlined in BLN-9939, page 15.

18. Now torque the 1/4–20 x 0.500 socket head screw

(1249 - inside of view hole) to 11-15 Nm (8-11 lbf•ft).

19. Install the neutral start switch (1236) and torque to

9-10 Nm (12-14 lbf•ft).

20. Make certain neutral start switch continuity is bro-

ken before or at 50 psi differential system pressure.

Measure system pressure through system gauge

ports (see BLN-9939).

21. Install expansion plug (1257).

Danfoss S40 P Installation guide

Danfoss S40 P Installation guide

Danfoss S40 P Installation guide

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