750-96 (revised 2010)
Model CB Packaged Boiler Manual
2-3
2.3 — Water Requirements
2.3.1.4 — Continuous Flow Through the Boiler
The system should be piped and the controls so arranged that there will be water circulation through the boiler
under all operating conditions. The operation of three-way valves and system controls should be checked to make
sure that the boiler will not be bypassed. Constant circulation through the boiler eliminates the possibility of strati-
fication within the unit and results in more even water temperatures to the system.
A rule of thumb of 1/2 to 1 G.P.M. per boiler horsepower can be used to determine the minimum continuous flow
rate through the boiler under all operating conditions.
Before initial firing or refiring after the boiler has been drained, the operator should determine that a flow of water
exists through the boiler.
2.3.1.5 — Water Circulation
FIGURE 2-1. Circulation Chart
The chart shows the maximum G.P.M. circulation rate of boiler water in relation to full boiler output and system
temperature drop.
2.3.1.6 — Multiple Boiler Installations
When multiple boilers of equal or unequal size are used, care must be taken to insure adequate or proportional
flow through the boilers. This can best be accomplished by use of balancing cocks and gauges in the supply line
from each boiler. If balancing cocks or orifice plates are used, a significant pressure drop (e.g., 3-5 psi) must be
taken across the balancing device to accomplish this purpose.
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