Primary/Secondary Piping; Variable Speed Pumping; Models Ch 991-2071 - Lochinvar Copper-Fin II CX401 Designer's Manual

CIRCULATOR PUMP
OPERATION
A pump control relay is optional on
CH 401-2071 heating boilers. When
designing a system to utilize primary /
secondary operation, specify a pump control
relay for intermittent pump operation.
WATER FLOW
REQUIREMENTS and
SYSTEM PIPING
Lochinvar boilers are generally capable of
operating within the design flow rates for the
building heating system. To ensure the most
efficient operation, a boiler needs adequate
water flow. Pump sizing, pipe sizing, and
piping layout must be taken into
consideration for proper system flow.
(Table L) provides Gallons Per Minute and
boiler head-loss at various temperature rises
for each boiler based on Btu/hr input. (Table M)
provides maximum and minimum flow data
for each model. These two charts will provide
assistance in system flow design.
(TABLE M) – MINIMUM & MAXIMUM
BOILER FLOW RATES
MODEL MINIMUM FLOW MAXIMUM FLOW
NUMBER (GPM)*
CH401
17
CH501 21
CH651 28
CH751 32
CH991 33
CH1261 42
CH1441 48
CH1801 61
CH2071 70
*Flow switch requires 20 GPM to allow boiler operation.
Variable Speed System Pump
High efficiency boilers require minimum flow
rates through the heat exchangers to operate
safely and efficiently. A variable speed
pump that reduces the flow rate, in the main
L o c h i n v a r
D E S I G N E R
system piping loop, below the minimum
requirements of the total boiler system must
not be installed.

Primary/Secondary Piping

Using a primary/secondary piping
arrangement can solve many system flow
complications.
(GPM)
60
60
This piping arrangement uses a dedicated
60
60
pump to supply flow to the boiler. The pump
90
90
is sized based on the required boiler flow
90
rate, boiler head-loss and head-loss in the
90
90
secondary system piping. A separate pump is
used to provide the desired flow for the
system. Primary/Secondary piping allows
the system and the boiler(s) to operate at their
optimum flow rate. The system works best
when the boiler(s) are supplied with pump
control relays which are used to cycle the
' -
S G U I D E C O P P E R F I N I I B O I L E R
HEAT EXCHANGER HEAD LOSS CHART
Models 401-751
Flow in Gallons Per Minute
(FIG. 17) BOILER HEAD LOSS CH 401-751
HEAT EXCHANGER HEAD LOSS CHART
Models 991-2071
Flow in Gallons Per Minute
(FIG. 18) BOILER HEAD LOSS CH 991-2071
6 1 5 - 8 8 9 - 8 9 0 0
IMPORTANT!
EXAMPLE
OF VARIABLE
SPEED PUMP
REQUIREMENTS:
4 - CHN2071
(Min. Flow = 70 GPM)
The combined "minimum"
flow for the boiler
system is
70 GPM x 4 = 280 GPM.
A variable speed pump
must not reduce the
system flow rate below
280 GPM.
19