Burnham 8H User Manual
Page 27
2
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
with By-Pass