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Page 15
SERIES 28A BOILER INSTALLATION AND OPERATION INSTRUCTIONS
Figure 15 - Relief & Safely Valve Piping
WATER BOILER PIPING
The supply and return connections should be sized
to suit the system, see Figures 13, 14, 16, 17 and Tables
5 & 6. Do not pipe the supply from the bottom port or
the return to the top port, the boiler will not work
properly. Typical water boiler piping arrangements are
shown in Figures 18 & 19. Swing joints should be used.
Install 3" nipples into the two 3" NPT tappings in the
front section and cap them.
NOTE: See CLEANING OF WATER BOILERS on page
18 before proceeding!
Supply Piping
Install a reducing bushing in the 6" NPT tapping in the
front section to obtain the correct supply pipe size,
Figure 13 and Tables 5 & 6.
Table 6 - Water Boiler Piping
Boiler Size Return Size Supply Size
# Sections NPT NPT
4 & 5 3 3
6 through 9 4 4
10 through 18 5 5
Note: Sizes based on 20°F, 11.1°C, ∆T for the system.
Return Piping 4 Through 9 Section Boilers
Install 3" x 4" NPT bushings in the two 4" NPT tappings
at the bottom of the back section. Install the two 3" NPT
x 6" nipples per Figure 16. Assemble the rest of the
return yoke as shown in Figure 16.
Table 7 - Boiler Water Content
Boiler Model Water Boilers Steam Boilers
Gallons
Liters
Gallons
Liters
28A-4 123
466
104
394
28A-5 150
568
126
477
28A-6 177
670
148
560
28A-7 204
772
170
644
28A-8 231
875
192
727
28A-9 258
977
214
810
28A-10 285
1079
236
893
28A-11 312
1181
258
977
28A-12 339
1283
280
1060
28A-13 366
1386
302
1143
28A-14 392
1484
324
1227
28A-15 419
1586
346
1310
28A-16 446
1689
368
1393
28A-17 473
1791
399
1511
28A-18 500
1893
412
1560
Return Piping 10 Through 18 Section Boilers
Install the two 4" NPT x 6" nipples per Figure 16.
Assemble the rest of the return yoke as shown in Figure
16.
Control Installation
Locate the temperature & pressure gage, low water
cutoff, high limit and operating controls per Figures 13
& 7. Optional controls must be installed in accordance
with the control manufacturers instructions and Figures
13 & 17.
NOTE: The front jacket panel MUST be installed
before any controls are attached to the front boiler
section!
CAUTION: The controls must be mounted in the
correct location and according to the control
manufacturer’s instructions or the boiler may not
function properly!
Water Column Piping
A variety of water level controls are available for the 28A.
The water column piping needed to properly mount each
control is available from Smith. Figure 17 shows a typical
water column piping arrangement. The 1" NPT x 7 1/2"
nipple is always installed in the lower water column
tapping, Figures 13 & 17 and Table 5.