2.If boiler is connected to heating coils located in air handling units where they may be exposed to refrigerated air, boiler piping must be equipped with flow control valves to prevent gravity circulation of boiler water during cooling system operation.
3.The piping diagrams shown (Figure 23, Detail “A” and Detail “B”) are recommended for optimum operation and long term reliability.
Burnham Commercial recommends maintaining temperature differential (drop) across the system
at 40°F or less, and return water temperature at minimum of 135°F.
Continued boiler operation for prolonged periods of time under conditions when temperature differential across the system exceeds 40°F and/or return water temperature stays below 135°F, may result in premature boiler failure due to flue gas condensation and/or thermal shock.
Pump flow rates and minimum boiler supply and return pipe sizes are shown in Table 4.
Figure 23: Recommended Boiler Piping for Circulator Zoned Heating Systems
Detail “A”: Blend Pump Piping | Detail “B”: Primary/Secondary Piping |
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