Boiler Circulator - Weil-McLain WM97+100 Manual

WM97+ Series 2
Install water piping
Head loss through boiler internal
piping
1. See Figure 42 for the head loss through boiler internal piping
for boiler top connections. This data is based on primary/
secondary piping (boiler internal by-pass valve OPEN).
2. For the special case of direct connection of WM97+70 or 110
boilers, see the information on page 47.
Head loss through boiler internal piping for top
boiler connections
WM97+70 or 110
Flow rate Head loss
(GPM) (Feet W. C.)
4 0.0
6 1.2
8 1.4
1.5
1.7
2.3
1. See Figure 43 for the head loss through boiler internal piping
for boiler bottom connections.
Head loss through boiler internal piping for
bottom connections
WM97+70 or 110
Flow rate Head loss
(Feet W. C.)
(GPM)
4 0.0
6 0.3
8
0.6
1.2
2.3
2.9
Part number 550-142-204/0117
-
GAS FIRED WATER BOILER
(continued)
(internal by-pass valve OPEN)
WM97+155
Flow rate Head loss
(GPM) (Feet W. C.)
8 2.2
2.7
3.3
4.0
4.8
5.9
WM97+155
Flow rate Head loss
(Feet W. C.)
(GPM)
8 1.3
2.1
3.0
4.2
5.5
7.1
— Boiler Manual

Boiler circulator

1. The boiler circulator is factory-installed in the boiler as shown
in this manual. The boiler circulator is selected to ensure
adequate flow through the WM97+ boiler.
relocate or use the boiler circulator in any
way other than shown in this manual.
Failure to comply could result in unreliable perfor-
mance and nuisance shutdowns from insufficient
flow.
System circulators and zone
circulators
1. Install a system circulator or zone circulators as shown in the
piping diagrams in this manual. These circulators must be
supplied by the installer.
1. Size circulators based on the flow rate required to achieve the
temperature change needed.
2. You can closely estimate temperature rise (or drop) through a
circuit by using the following formula, where TD is tempera-
ture rise (or drop), FLOW is flow rate (in gpm), and BTUH
is the heat load for the circuit:
=
:
1. Consider a system loop for a system with total heating load
equal to 210,000 Btuh. The desired temperature drop through
the system piping is 20°F. Then the required flow rate is:
=
1. The circulator must be capable of delivering the required flow
against the head loss that will occur in the piping.
2. Determine the pipe size needed and the resultant head loss
using accepted engineering methods.
3. The simplified pipe sizing here is limited to residential sys-
tems, and does not include systems with fan coil units or
radiant tubing.
The following simplified method for pipe and
circulator sizing must be limited to residential ap-
plications using baseboard (finned or cast iron),
cast iron radiators or convectors. DO NOT apply
for radiant heating, fan coil units or commercial
installations.
=
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