Operation, Figure 1: bolt size and torque requirements – Thrush Double Wall Steam to Water U-Tube Heat Exchanger User Manual
Page 2
OPERATION
Start up - Open cold side first; then start hot side fluid slowly to gradually bring unit to operating
condition. Bring unit from ambient temperature up to operating temperature gradually. Do not
introduce hot or cold fluids suddenly. This could damage the unit and void the warranty.
Shut down - Always close off flow of hot fluid first.
Important - Never admit hot fluid suddenly when unit is empty or cold. Do not shock with cold water
when unit is hot.
Gasket Creep is inherent to most gasket joints, and retorquing is required. The greater the operating
temperature and pressure the greater the problem can become. It is imperative that the head bolts
be torqued after installation, after initial startup, and inspected seasonally to be sure the bolts are
torqued correctly.
The bolts should be torqued incrementally to 30%, 60%, and then to 100% of the appropriate value
in Figure 1. They should be torqued in the sequential order of the appropriate pattern in Figure 2.
Figure 1: Bolt size and Torque requirements
Heat Exchanger
Size
Bolt
Size
Number
of Bolts
Torque Ft/Lb.
150# Flgs.
Heat Exchanger
Size
Bolt
Size
Number
of Bolts
Torque Ft./Lb.
300# Flgs.
4"
.62
8
30
4"
.75
8
100
6"
.75
8
50
6"
.75
12
100
8"
.75
8
50
8"
.87
12
160
10"
.87
12
80
10"
1.00
16
245
12"
.87
12
80
12"
1.12
16
390
14"
1.00
12
123
14"
1.12
20
390
16"
1.00
16
123
16"
1.25
20
545
18"
1.12
16
195
18"
1.25
24
545
20"
1.12
20
195
20"
1.25
24
545
22"
1.25
20
273
24"
1.25
20
273
26"
1.25
24
273
Figure 2: Sequential Order for Torquing Flange Bolts
1
2
3
4
5
6
7
8
1
5
3
7
2
6
4
8
9
10
11
12
13
14
15
16
1
5
9
3
7
11
2
6
10
4
8
12
8 BOLT
12 BOLT
16 BOLT
20 BOLT
8
16
1
9
5
13
3
11
7
15
2
10
6
14
4
12
17
18
19
20
24 BOLT
1
13
5
17
9
3
15
7
19
11
2
14
6
18 10
4
16
8
20
12
21
22
23
24