Weil-McLain WM97+70 Manual page 55

WM97+ -
gas fired water boiler
Multiple boiler installations
Sequencing multiple WM97+ boilers
1. Use a multiple-boiler controller, such as the Weil-McLain BCP,
BMC or BSC, to sequence boilers. Locate temperature sensors as
required in the controller manual.
Easy-Fit® piping installation
1. Main header and Easy-Fit® Manifold pipe sizing.
a. Size system piping as required for the flow.
b. Install tees or crosses in the system piping for Easy-Fit® mani-
folds as shown in Figure 61 or Figure 62. Size manifolds to
handle total connected boiler output as shown.
2. Provide connections in main header for Easy-Fit® manifolds as
close as possible to the midpoint of multiple boilers.
a. Use tees for four or less boilers, as in Figure 61.
b. Use either tees (Figure 61) or crosses (Figure 62) for five or
more boilers.
3. Manifold placement:
a. To alternate spacing for supply and return lines to boilers,
reverse the short-end and long-end of the manifolds as shown
in Figure 61 and Figure 62.
b. Return manifold must be on the return side of the main and
supply manifold must be on the supply side of the main. Draw-
ings in this manual show flow in system main from right to
left. For system flowing left to right, reverse the locations of
the manifolds accordingly.
4. Connect from Easy-Fit® manifold branches to boiler supply and
return connections using copper or steel pipe, sized for the required
flow rate.
5. Install an isolation valve on the supply and return of each boiler
as shown in the piping diagrams in this manual. Some local codes
may require the use of individual water level controls and limits
on each boiler because isolation valves are installed.
6. Install main system air eliminator and primary circulator in sup-
ply piping as shown in piping diagrams. Place expansion tank on
suction side of system circulator as shown.
7. Install system accessories as shown in drawings.
8. Piping recommendation drawings:
a. Figure 61 and Figure 62 show details of Easy-Fit® manifolds.
b. Figure 63, page 56 is a schematic piping drawing showing the
locations of typical boiler piping and system piping, including
limits and other devices often required by local codes.
c. Figure 64, page 57 and Figure 65, page 58 are three-dimensional
piping drawings of typical multiple boiler installation.
d. Figure 66, page 59 shows recommended piping when an isolat-
ing heat exchanger is needed.
9. If desired, other primary/secondary piping arrangements can be
used.
The boiler internal primary/secondary by-pass valve
must be CLOSED
as shown in this manual. This allows the boiler internal
circulator to circulator water to and from the manifolds.
Part number 550-142-085/0712
— Boiler Manual
for multiple boiler installations piped
(continued)
Maximum connected load per manifold:
2-inch manifold —
3-inch manifold — 1400 MBH
4-inch manifold — 2900 MBH
Single-sided EZ-Fit Header connection
Figure 61
Double-sided EZ-Fit Header connection
Figure 62
450 MBH
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