Instruction Manual
D101728X012
3710 and 3720 Positioners
September 2017
43
Disassembling the 3722 Converter
See figure 31 for key number locations.
1. Turn off electrical power to the converter. Release all supply pressure from the positioner.
2. Remove the cap (key 72) and disconnect the field wiring from the terminal block.
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If a grounding wire is used inside the housing compartment, disconnect the wire from the internal housing
ground screw (key 81).
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If an external grounding wire is used, disconnect the grounding wire from the external ground screw (key 81).
3. To remove the converter module, remove the two screws (key 80) and pull the module out of the housing. Inspect
the O‐ring (key 77) and replace it, if necessary.
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If you are replacing the converter module only, obtain a replacement converter module and refer to the
procedure for assembling the converter. After replacing the converter module, calibrate the pneumatic portion
of the positioner by performing the calibration procedures. There is no converter module calibration.
4. Disconnect the supply tubing, output tubing, and conduit from the converter.
5. Remove the two socket head screws (key 84) and remove the converter from the positioner base plate (key 16,
figure 31). Inspect the two O‐rings (key 85) and replace them if necessary. Apply lubricant (key 82) to the O‐rings
before replacement.
Assembling the 3722 Converter
Refer to figure 32 for key number locations, unless otherwise indicated, while assembling the converter. If the
converter was removed from the pneumatic positioner, re‐install using the following instructions.
1. Inspect the O‐rings (key 85) and replace, if necessary. If the O‐rings are in good condition, apply lubricant (key 82)
to the O‐rings and install them in the recessed areas surrounding the input and supply ports on positioner base
plate (key 16, figure 31). Be sure the O‐rings remain in place.
2. Apply sealant (key 64 or 83) to the two socket head screws (key 86). Then, properly align the converter and attach it
to the positioner base plate using the socket head screws. Be sure the O‐rings remain in place. Tighten the socket
head screws.
3. Apply sealant (key 64 or 83) and install pipe bushings (key 68), pipe tees (key 56), gauges (key 53, 54, or 55), pipe
plugs (key 57 or 86), tire valves (key 62), or diagnostic connectors as applicable to the converter.
4. If the converter module was removed from the housing, apply lubricant (key 82) to the O‐ring (key 77) and insert
the converter module into the housing.
5. Replace the two screws (key 80) and tighten them.
6. Connect the supply tubing, output tubing, and conduit to the converter.
7. Connect the wiring to the terminal block by using installation procedures.
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If an internal grounding wire is used inside the housing compartment, connect the wire to the internal housing
ground screw (key 81).
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If an external grounding wire is used, connect the grounding wire to the external ground screw (key 81).
8. Inspect the O‐ring (key 79) inside the converter cap (key 72). Replace, if necessary. Lubricate (key 82) the O‐ring
and install it inside the cap.
9. Lubricate (key 87) the threads of the cap and replace it.
10. If the converter module was replaced, calibrate the pneumatic portion of the positioner by performing the
procedures in the Calibration section of this manual. Do not attempt to calibrate the converter module. There are
no converter module adjustments.
