Dismantling And Reassembly - ABB 268D/V Operating Instruction

DISMANTLING AND REASSEMBLY

WARNING - Process fluids and/or pressure retained
in the transmitter primary unit can cause severe injury and
death or damage to the equipment. It is the user
responsibility to make sure that no pressure is applied
before removing the instrument from service or when
draining or venting.
Dangerous fluids.
In case of toxic or otherwise dangerous process fluid, take
any precautions as recommended in the relevant Material
Safety Data Sheet.
CAUTION - Dismantling and reassembly should not
be carried out on site because of the risk of damage to
components and printed circuits as a result of adverse
environmental conditions such as humidity,dust,etc. The
dismantling and reassembly procedures given below should
be carried out in the listed order to avoid instrument
damage.
Required tools
2 mm Allen key
3 mm Allen key
Small Phillips screwdriver
Small flat-bladed screwdriver
17 mm spanner
17 mm torque wrench
- (Range > 52 Nm - 39 foot lbs)
Dismantling
a) Screw down completely the cover locking screw, electronics
side, using the 3 mm Allen key
b) Unscrew and remove the covers
c) Unscrew the two fixing screws and remove the
secondary electronic assembly
d) Unplug the sensor cable
e) Remove the tang grub screw using the 2 mm Allen key
f) Unscrew the housing taking care not to damage the
sensor cable or the connector
g) Loosen and remove the four flange fixing bolts using a
17 mm. spanner.
- 20 -
Reassembly
Check that the "O" rings are not damaged: if in replace.
WARNING - Assembling flanges with incorrect
fixing bolts and nuts and improper "O rings" can cause
fracture or overstressing of bolts and release of pressurized
process material. Use only official spare parts (*) included
in the supplementary documentation, follow the
reassembly procedure herebelow described and do not
exceed the specified torque limits. DO NOT REMOVE the
"O ring" fitted in the sensor neck: it provides the housing
a degree of protection.
a) Refit the flange fixing bolts with a torque of 20 Nm (15 ft lbs)
using a 17 mm. torque wrench.
Note: 1 Nm is equivalent to 0.738 ft lbs (8.85 in lbs
b) Insert the sensor cable in its recess at the bottom of the
housing.
c) Screw the housing down completely until the nesting of
housing/sensor assy is reached, then unscrew by one
complete turn maximum. Rotate the topwork in the
desired position and lock it with the tang grub screw
previously removed.
d) Plug the sensor cable to the secondary electronics. Fix
the electronic circuit by its screws.
e) Refit the covers and tighten securely.
WARNING - For Hazardous Location installations,
at least eight (8) threads on the cover must be engaged in
order to meet the flameproof (explosion-proof) requirements.
f) Unscrew the cover locking screw to secure the covers.
This is mandatory to meet "Flameproof requirements"
for Hazardous Areas installation.
PRESSURE TEST WARNING
Once reassembled the process flanges and the transducer,
a pressure test is required. At this purpose, apply a
hydrostatic pressure of the maximum overrange pressure
rating to both process connections simultaneously. Wait
for one minute, then verify that no leakages occurred,
otherwise repeat the assembly procedure and the pressure
test.
(*) The spare parts list is available at: www.abb.com
- searching for: SL262_4D.pdf
or from local ABB representatives.