Flowserve 3400IQ Digital Positioner - Manual (Page 57)

Logix 3400IQ Digital Positioner FCD LGENIM3401-00 – 06/06
flowserve.com
9. Install the plastic board cover. Insert the three retaining screws through the plastic cover into the
threaded boss and tighten evenly, using a Phillips screwdriver. Do not overtighten (see Figure
16).
10. Reinstall all covers.
8.4 Spool Valve
The spool valve routes the supply air to one side of the actuator while venting the opposite side (see
Figure 1). The position of the spool valve is controlled by the driver module.
Replacing the Spool Valve
To replace the spool valve, refer to Figures 12, 14 and 21 and proceed as outlined below. The
following tools are required:
• Phillips screwdriver
1. Make sure the valve is bypassed or in a safe condition.
2. Disconnect the power and air supply to the unit.
3. Remove the spool valve cover by removing the screw and sliding the cover assembly backwards
until the tab is clear of the slot. It is not necessary to remove the sheet metal cap, hydrophobic
filter, or O-ring from this assembly (Figure 18).
c WARNING: The spool (extending from the driver module assembly) is easily damaged.
Use extreme caution when handling spool and spool valve block. Do not handle the
spool by the machined portions of spool. The tolerances between the block and spool
are extremely tight. Contamination in the block or on the spool may cause the spool to
hang.
4. Remove the spool valve block by removing the two Phillips-head screws and carefully sliding
the block off the spool (Figure 14).
5. Carefully remove spool by sliding end of spool out of connecting clip. Excessive force may bend
the spool.
6. Verify that the three O-rings are in the counterbores on the machined platform where the new
spool valve block is to be placed (Figure 22).
7. Carefully slide the spool into the connecting clip of the driver module assembly.
8. Carefully slide the block over the spool, using the machined surface of the housing base as a
register (Figure 14). Slide the block toward the driver module until the two retaining holes line
up with the threaded holes in the base.
9. Install two spool valve screws and tighten securely with a Phillips screwdriver (see Figure 14).