CVHE-SVN02D-EN
16
Water Piping
Bolt-Tightening Sequence for
Water Piping Connections
A bolt-tightening sequence for
flanges with flat gaskets or O-rings is
described below and shown in
Figure 10. Remember that
improperly tightened flanges may
leak.
Note: Before tightening any of the
bolts, align the flanges. Flange bolt
torque requirements are given in
Table 6.
Flanges with 4, 8 or 12 Bolts
See Figure 10. Tighten all bolts to a
snug tightness, following the
appropriate numerical sequence for
the flange. Repeat this sequence to
apply the final torque to each bolt.
Flanges with 16, 20 or 24 Bolts
See Figure 10. Following the
appropriate numbered sequence,
tighten only the first half of the total
number of bolts to a snug tightness.
Next, sequentially tighten the
remaining half of the bolts in the
proper order.
Flanges with More than 24
Bolts
Refer to Figure 10 and sequentially
tighten the first 12 bolts to a snug
tightness. Tighten the next 12
consecutively numbered bolts in
sequence, to the final torque.
Then, apply final torque to the first
12 bolts and the bolts not yet
tightened (i.e., unnumbered bolts in
Figure 10). Be sure to start with bolt
“1” and move progressively around
the flange in a clockwise direction.
Evaporator Water Box Covers
See Figure 10. Ensure that the water
box head rests tightly against the
tube sheet; then snugly tighten the
26 bolts in sequential order.
If excessive tube sheet crown
prevents the head from contacting
the tube sheet, tighten the bolts
located where the greatest gaps
occur. Be sure to use an equal
number of bolt turns from side to
side.
Pressure Testing
Waterside Piping
Water side design pressure is either
150 or 300 Psig
CAUTION
Equipment Damage!
Do not over pressurize the system
or exceed design pressure. Over
pressurization can result in
equipment damage. Always
perform as a hydro pressure test
with water present in piping and
water boxes.
Table 6. Flange bolt torque recommendations for o-ring and flat-gasket
piping connections
Bolt Size Gasket Type
Inch (mm) O-Ring Flat
3/8" 9.5 25 (34) 12-18 (16-24)
1 /2" 13 70 (95) 33-50 (45-68)
5/8" 16 150 (203) 70-90 (95-122)
3/4" 19 250 (339) 105-155 (142-210)
Note: Torques provided in Ft/Lbs. (Newton/metres) Bolt size is determined by the diameter of bolt shank.
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