Cleaver-Brooks CBH 40 - Steam Boiler

Chapter 2- The Pressure Vessel
Boiler
Boiler
System Temperature Drop - Degrees f'
Size
Output
10
20
30
40 50
60
70 80 90 100
( 1 ()()())
(BHP)
Btu/Hr
Maximum Circulating Rate - GPM
15 500 100 50 33
25 20 17 14 12 11 10
20
670
134
67 45
33
27 22 19 17 15
13
30
1,005
200
100
67 50
40
33 29
25 22
20
40
1,340
268 134 89
67
54 45
38 33
30 27
50
1,675
335
168 112 84 67 56 48
42 37
33
60
2,010
402
201 134
101
80
67
58 50
45 40
70
2,345
470 235 157 118
94
78
67 59 52 47
80
2,680
536
268
179 134 107
90
77 67 60
54
100 3,350 670
335 223 168
134 112
96
84
75 67
125 4,185
836
418
279
209 168 140
120 105
93
84
150 5,025 1,005
503
335 251 201 168
144
126
112
100
200
6,695 1,340
670
447
335 268
224 192 168
149 134
250
8,370 1,675
838 558
419
335
280 240 210
186 167
300
10,045 2,010 1,005
670
503 402
335 287
251
223
201
350
11,720 2,350 1,175 784 587 470 392 336 294
261
235
400
13,400
2,680 1,340
895
670 535
447
383 335 298
268
500
16,740 3,350 1,675 1,120
838
670 558
479
419
372
335
600
20,080 4,020 2,010
1,340 1,005
805 670
575 502
448 402
700
23,430 4,690 2,345 1,565
1 '175
940 785 670
585
520
470
800
26,780 5,360 2,680 1,785 1,340 1,075
895 765
670 595 535
FIGURE 2-1. CIRCULATION CHART
for this reason that the internal boiler pressure, as
indicated on the water pressure gauge, must be
held to the level shown in Fig. 2-2.
When initially firing a newly installed boiler or
when cutting an existing boiler into an operating
system, the boiler or boilers to be cut into
operation MUST be pressurized equal to the
system and/or other boilers prior to cutting in.
It is advisable to have a thermometer installed in
the return line to indicate return water tem-
perature. With this determined and with the sup-
ply water temperature to system known, the tem-
perature differential will be established. With
knowledge of the pumping rate, the operator can
easily detect any excessive load condition and take
appropriate corrective action. (See Figure 2-1 ).
Special caution must be taken to guard against
any condition, or combination of conditions which
might lead to the transfer of cold water to a hot
boiler or hot water to a cold boiler. This is par-
ticularly true in the case of boilers which are
operated for purposes other than supplying hot
water for the normal system load (as an example,
boilers equipped with coils for domestic hot water).
It cannot be over emphasized that rapid changes in
temperature within the boiler can, and sometimes
do, cause damage.
2. STEAM BOILER
Feed Pump Operation
Make certain that all valves in the water feed line
are open BEFORE turning on the pump motor to
prevent possible damage to feed pump mechanism.
After opening valves, momentarily energize feed
pump motor to establish correct pump rotation.
With correct rotation, close boiler feed pump en-
trance switch. Pump should shut down when water
level reaches proper level shown in Figure 2-3.
Feedwater pumps must have adequate capacity to
maintain required water level under all operating
conditions. Check feedwater pumps periodically
and maintain as necessary to prevent unexpected
breakdowns.
NOTE: Prior to operating pump, carefully check
alignment of flexible coupling if one is
used. A
properly aligned coupling will last
2-3