PIPE THE BOILER
control valve and boiler circuit pump piped off of the system as a secondary loop. See Figure 3.6 for a single boiler and Figure 3.7 for multiple boilers.
D.CHILLED WATER SYSTEMS
1.If the boiler will be used in conjunction with a refrigeration system, the chilled medium must be placed in parallel with the boiler and proper valves applied to prevent the chilled medium from entering the boiler. See Figure 3.5.
E.HIGH FLOW RATE PIPING
1.For flow rates higher than given in Table 3.1, provide bypass piping around the boiler to limit the boiler flow to that given in the table or pipe the boiler in a secondary loop with its own pump as shown in Figure 3.3.
F.MULTIPLE BOILER INSTALLATIONS
1.For multiple boiler installations, piping the boilers in a secondary loop is recommended. Each boiler should be provided with its own pump and piped off of the secondary loop header. See Figure 3.7 for systems with return temperature above 130°F on gas boilers or 150°F on oil boilers. For low temperature systems, see Figure 3.4 (constant low temperature systems) or Figure 3.8 (variable low temperature systems).
2.You can use alternative piping if desired, such as parallel piping or series piping in the primary system loop. But these systems are less versatile.
a)With parallel piping, for instance, the system flow conditions change if one or more of the boiler
b)With series piping, temperature control to the system is difficult because the temperature rise equals the sum of the rises through each boiler. Series piped boilers cannot be isolated for servicing.
Figure 3.5: Piping to Isolate Boiler from Chilled Medium on Chiller Systems
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