Smith Cast Iron Boilers Series 28A - Manual (Page 15)

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.