A-22
Section 4
Model 199 Differential Pressure Unit (DPU)
4. Install the new range spring assembly onto the push rod, and replace the
spring retainer screw.
5. If the pointer is set above zero, rotate the spring adjustment clockwise
until the pointer is set at zero. If the pointer is below zero, rotate the
spring adjustment counterclockwise until the pointer is set at zero.
6. Replace and tighten the lock nut. If the pointer shifts from zero, loosen
the lock nut and reset the pointer as in step 5. Tighten the lock nut.
7. Replace the low-pressure housing and install NEW bolts (new gaskets
are also recommended). Torque the bolts in accordance with
Table 4.2,
page A-19
.
WARNING: Do not reuse housing bolts. Reuse of housing bolts, espe-
cially in critical applications like hydrogen sulfide and salt water expo
-
sures, can result in severe injury, death or substantial property damage
due to bolt failure.
8. Calibrate in accordance with the manual for the actuated instrument.
3-3/4-inch Diameter Bellows Without Kickoff Spring (>47" w.c.)
1. Remove the instrument from service.
2. Remove the pressure housing bolts and the low-pressure housing.
3. With the pointer set at zero, remove the lock nut retainer nuts, and the
range spring assembly. To remove the range spring assembly, rotate the
assembly counterclockwise while pulling outward on the assembly.
IMPORTANT: The pointer will shift from zero. This is a normal action and the pointer
should not be readjusted at this point.
4. Thread the new assembly onto the push rod, and align the holes in the
range spring assembly with the spring posts. Replace and tighten the
retainer nuts.
5. Using a spanner wrench, rotate the spring adjustment until the pointer
is set at exact zero. Replace and tighten the lock nut. The pointer must
remain at the zero setting. If the pointer shifts from zero, loosen the lock
nut and repeat this step.
6. Replace the low-pressure housing and install NEW bolts (new gaskets
are also recommended). Torque the bolts in accordance with
Table 4.2,
page A-19
.
WARNING: Do not reuse housing bolts. Reuse of housing bolts, espe-
cially in critical applications like hydrogen sulfide and salt water expo
-
sures, can result in severe injury, death or substantial property damage
due to bolt failure.
7. Calibrate in accordance with the manual for the actuated instrument.
Содержание BARTON 289A
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