Flowserve NT3000 Series - Manual (Page 6)

NT 3000 Series Electro-Pneumatic Transducer Module FCD VLAIM0047-00 - 09/04
6
Adjusting the Pressure
Regulator Output
The setpoint of the internal pressure regulator is set at the factory
and normally does not need adjustment. However, if it is necessary to
check or adjust the pressure regulator, refer to Figure 8 then proceed as
follows.
1. Disconnect the positioner’s air supply (or calibration manifold).
2. Detach the vent cover (20) and unscrew the vent element (21). For
vented models, the pipe fitting replaced the vent cover and element.
3. Plug the vent port with a 1 ⁄
8
-inch NPT plug, being certain the plug is
airtight.
4. Plug the electrical port with a ½-inch NPT plug, being certain the
electrical port is airtight.
5. Be certain housing cover (1) is screwed on airtight.
6. Reconnect or turn on the supply pressure to the positioner or
calibration manifold.
7. Observe pressure indicated by the pressure gauge on the NT 3000
transducer. With the ports plugged and cover on, the indicated
pressure is the setpoint of the internal pressure regulator. Its value
should be 23 psi (±3 psi). If the setpoint is within this range it
needs no further adjustment, proceed to Step 9. If it is not within
this range, continue with Step 8.
8. Remove pressure regulator setscrew (40). Apply a drop of thread
locking compound (Loctite No. 222 or equivalent) to the setscrew.
Install and turn the setscrew clockwise until the pressure indicated
by the I/P transducer pressure gauge on the NT 3000 transducer is
23 psi (±3 psi).
9. Disconnect the air supply pressure to the positioner (or calibration
manifold).
10. Remove the 1 ⁄
8
-inch NPT plug from the vent port and reinstall the
vent element (21) and the vent cover (20) into the I/P transducer
housing. If vented model is used, replace pipe fitting instead of vent
cover and element.
11. Remove the ½-inch NPT plug from electrical port.
12. Reconnect the air supply pressure to the positioner.
Adjusting the Pressure Modulator
The pressure modulator is factory set and normally does not need
adjustment; however, if adjustment is necessary refer to Figures 6 and
7, proceed as follows.
NOTE: Although the pressure modulator can be adjusted using the
standard output pressure gauge on the NT 3000 transducer, its
accuracy is ±3 percent. It is recommended that the standard gauge be
removed for calibration and more accurate calibration equipment of
±0.1 percent of span be used or use a manifold block with an accurate
pressure sensor. The pressure gauge port is
1 ⁄
8
-inch NPT.
1. Remove the NT 3000 transducer housing cover (1).
c WARNING: Disconnect power to the I/P transducer before
removing the housing cover in explosive atmospheres;
otherwise, personal injury may occur.
2. Disconnect the loop power electrical connection from the circuit
board.
3. Apply supply air pressure to the NT 3000 transducer and observe
the pressure indicated by the NT 3000 transducer pressure gauge.
If the indicated pressure is 2.00 ±0.20 psi the pressure modulator is
adjusted correctly; reconnect the loop power electrical connection
to the circuit board and reinstall the housing cover. If the indicated
pressure is not 2.0 ±0.20 psi, turn off the supply pressure and
continue with step 4.
4. Remove the three screws (3) holding the circuit board in place and
carefully pull the circuit board straight out of the housing. Discon-
nect the pressure modulator electrical connector from the bottom
of the circuit board.
5. Securely plug the pressure sensor port with a .188 inch diameter
rod. Be careful not to damage the pressure sensor O-ring (46) in
the pressure sensor port.
c WARNING: Rod may be ejected from port with high
pressures. Use care to avoid personal injury.
A damaged O-ring must be replaced with the appropriate part from
Soft Goods Kit 5. Remove O-ring with a small screwdriver.
6. Connect the air supply pressure to the positioner.