Specifications

Part number 550-100-090/0809
55
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
ADVANCED INSTALLATION
Manifolded combustion air optionFigure 59
Manifolded combustion air option
Multiple Ultra boilers can use a common combustion air manifold.1.
See a. Figure 126, page 122 for minimum cross sectional area of
combined air ducts.
Provide minimum clearance to adjacent vents and grade/snow line b.
as shown in Figure 59.
Provide minimum free area in duct (adjusted for louver restriction) c.
of
1 square inch per 2,000 Btuh total boiler input.
If combustion air damper is used, wire to boilers to prevent opera-d.
tion 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. Failure to comply could result in severe personal
injury, death or substantial property damage.
Prepare boiler location — multiple boilers
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 126, page 122 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) Ultra-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