Instruction Manual
D101728X012
3710 and 3720 Positioners
September 2017
41
the alignment pins on the input module. If the spool valve (key 1) has not been removed, use care when positioning
the input module and summing beam assembly. Make sure the spool extending from the spool valve body properly
engages the spool flexure.
Figure 30. Spool Valve and Summing Beam
A6044‐1
LARGER VIEW OF SPOOL HEAD
SPOOL
FLEXURE
SPOOL
HEAD
SPOOL
FLEXURE
CLEARANCE
0.381 - 0.762 mm
0.015 - 0.030 INCHES
SUMMING
BEAM ASSY
SPOOL VALVE ASSY
SPOOL RELIEF
SPOOL
HEAD
5. Secure the assembly with the four machine screws (key 3).
Assembling the Spool Valve, Action Block, and Gasket
1. Place the action block gasket (key 29) on the mounting area found on the positioner base plate. Place the action
block (key 28) on the gasket and secure it to the base plate using the four machine screws (key 3).
2. Inspect the three O‐rings (key 2) found between the spool valve (key 1) and the action block. Replace the O‐rings, if
necessary.
Note
See figure 26. Handle the spool valve body and spool with care. The body and spool are manufactured to precise tolerances and
are prepared as a matched set.
3. Be sure the spool valve is ready for service. Clean or replace it, if necessary.
Note
properly engages the summing beam. Start the two machine screws (key 3) so the spool valve is loosely held in
position on the action block.