PVI Industries PV500-26 User Manual

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 Boiler Water Heater  
 
10 
 
4.  When replacing the heat exchanger head, use a torque wrench to tighten the bolts/studs and nuts. 
Use the following chart as a guide. All torque values apply to well-lubricated nut bearing surfaces. 
 
TIGHTENING TORQUES 
 
COMPRESSED FIBER GASKETS 
 
Bolt 
Dia. 
Recommended 
Torque 
ft-lbs 
 
Torque 
Increment 
 
Max. 
Torque 
1/2" 40 
60 
5/8" 80 
5  120 
 
 
SPIRAL WOUND GASKETS 
 
Bolt/Stud 
Dia. 
Recommended 
Torque 
ft-lbs 
 
Torque 
Increment 
 
Max. 
Torque 
1/2" 40 
60 
5/8" 80 
5  120 
3/4" 120 
200 
7/8" 200 
10  320 
1" 300  10  490 
1 1/8" 
450 
10 
710 
1 1/4" 
600 
10 
1000 
 
 
 
5.  Tighten uniformly and in a diametrically staggered pattern as illustrated below: 
 
 
 
WARNING: It is extremely important to follow 
a proper tightening sequence. If not followed, 
the flanges can become cocked and a leak 
will result. When tightening flanges with 
spiral wound gaskets, if cocking occurs, the 
result can be deformation and non-repairable 
damage to the gaskets in addition to a 
resultant leak. Any gasket leak can result in 
potential injury to adjacent personnel.