Advanced User Guide

Part number 550-100-160/0715
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CONDENSING GAS BOILER — Advanced Manual
™
Placing multiple boilers
1. Locate multiple boilers with spacings shown in Figure 3.
Provide the indicated clearances around boilers for ac-
cess and servicing.
If recommended dimensions are not possible,
provide at least the minimum clearances given
in the Evergreen boiler manual. Also follow
local codes.
2. If boilers are floor-mounted, construct a boiler founda-
tion if boiler room floor is uneven or if there is a danger
of flooding. Size the foundation to allow for clearance
and spacing dimensions shown in Figure 3.
3. Provide a minimum 30-inch walkway in front of the
boilers to ensure accessibility.
4. Uncrate, assemble and mount boilers according to in-
structions in the Evergreen boiler manual.
5. Provide clearances needed for installation of venting, air
piping, gas piping, expansion tank, primary circulator
and other accessories. Clearances must comply with all
applicable codes.
Manifolded combustion air option
1. Multiple Evergreen boilers can use a common combus-
tion air manifold.
a. Provide minimum clearance to adjacent vents and
grade/snow line as shown in Figure 4.
b. Provide minimum free area in duct (adjusted for
louver restriction) of
1 square inch per 2,000
Btuh
total boiler input. See below. Also see infor-
mation in Boiler Ratings section of boiler manual.
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 combined vent piping. Flue gas leakage
and boiler component damage can occur. Fail-
ure to comply could result in severe personal
injury, death or substantial property damage.
DO NOT use common venting — the mani-
fold option is only for combustion air — all
vent pipes must be routed and terminated
individually as described in this manual.
2. Calculate required cross sectional area of combined
combustion air duct (for area in square inches):
MINIMUM DUCT AREA
= TOTAL MBH INPUT DIVIDED BY 2
3. Example: A multiple boiler system with six (6) EVG 220
boilers has a total input of 6 x 220 = 1320 MBH
(1,320,000 Btuh). The required duct cross sectional
area would be:
MINIMUM DUCT AREA
= 1320 DIVIDED BY 2
= 660 sq. inches
Figure 3 Side-to-side mounting of multiple Evergreen
boilers
Figure 4 Manifolded combustion air option
Multiple boiler installations