Specifications
Part number 550-142-120/0113
WM97+ gas-fired water boiler — Boiler Manual
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Multiple boiler installations
Placing multiple boilers
1. Locate multiple boilers with spacings shown in Figure 63.
2. Provide indicated clearances around boilers for access and servic-
ing. If recommended dimensions are not possible, provide at least
the minimum clearances given on page 9. Also follow local codes.
3. The recommended clearance of 41½ inches below the boiler en-
sures room for further addition of a CWH unit if desired.
4. Provide a minimum 30-inch walkway in front of the boilers to
ensure accessibility.
5. Uncrate, assemble and mount boilers according to instructions
in this manual.
6. Provide clearance for installation of venting, air piping, gas piping,
expansion tank, primary circulator and other accessories.
Manifolded combustion air option
1. Multiple WM97+ boilers can use a common combustion air
manifold.
a. Provide minimum clearance to adjacent vents and grade/snow
line as shown in Figure 64.
b. Provide minimum free area in duct (adjusted for louver restric-
tion) of
1 square inch per 2,000 Btuh total boiler input (or
see Figure 138, page 134).
c. If combustion air damper is used, wire to boilers to prevent
operation except after damper has opened.
ONLY air piping can be combined. DO NOT use com-
bined vent piping. Flue gas leakage and boiler compo-
nent damage can occur. Failure to comply could result
in severe personal injury, death or substantial property
damage.
DO NOT use common venting — the manifold option is
only for combustion air — all vent pipes must be routed
and terminated individually as described in this manual.
See Figure 138, page 134 for minimum cross sectional
area of combined air ducts.
— OR —
Calculate required cross section (for area in square
inches):
MIN. AREA = TOTAL MBH INPUT DIVIDED BY 2
Example: A multiple boiler system with (6) WM97+155
boilers has a total input of 6 x 155 = 930 MBH (930,000
Btuh). The required duct cross sectional area is:
MIN. AREA = 930 DIVIDED BY 2 = 465 sq. inches
Figure 63 Side-to-side mounting of multiple WM97+
boilers
Figure 64 Manifolded combustion air option