Watts Aerco INN 1060N - Combustion Air Pipe Sizing

Innovation Water Heaters – Edge [i] Controller
Venting and Combustion Air Design Guide
TAG-0090_A • GF-5056 • 2/20/2020 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 14 of 39
TABLE 2: Summary of Minimum Required Air Openings
For Mechanical Room Combustion & Ventilation Air
Model
Two Openings
from within the
Building, Each
having an
opening, in
2
(cm
2
)
Two Direct or
Vertical Duct
Openings, Each
having an
opening, in
2
(cm
2
)
Two Horizontal
Ducts, Each
having an
opening, in
2
(cm
2
)
Single
Permanent
Opening, in
2
(cm
2
)
INN 600N
600 in
2
(0.39 m
2
)
150 in
2
(0.97 m
2
)
300 in
2
(0.19 m
2
)
200 in
2
(0.13 m
2
)
INN 800N
800 in
2
(0.52 m
2
)
200 in
2
(0.13 m
2
)
400 in
2
(0.26 m
2
)
270 in
2
(0.17 m
2
)
INN 1060N
1060 in
2
(0.68 m
2
)
265 in
2
(0.17 m
2
)
530 in
2
(0.34 m
2
)
355 in
2
(0.23 m
2
)
INN 1350N
1360 in
2
(0.87 m
2
)
340 in
2
(0.22 m
2
)
680 in
2
(0.44 m
2
)
455 in
2
(0.29 m
2
)
2.4. Combustion Air Pipe Sizing
In computing the pressure loading effect of the combustion piping system, an equivalent straight-
length of piping is used. This equivalent length of piping is the combined sum of all equivalent
lengths of piping and piping components used in construction, including:
1. All straight horizontal and vertical pipe sections.
2. All equivalent lengths of fittings, bends and end terminations.
3. All equivalent lengths associated with extrance or transition effects, for example a
sudden expansion or contraction.
Table 3 provides the required combustion pipe size for the Innovation-Edge water heaters along
with some rule-of-thumb guidelines for estimating the equivalent lengths of common piping
components.
TABLE 3: Rule-of-Thumb Maximum Combustion Air Run Lengths
Model No.
Minimum
Pipe
Diameter
Maximum
Length
Equivalent
Ft. (m)
Equivalent Pipe Lengths
Examples
Sharp 90°
Elbow
Equiv. Ft (m)
45° Elbow
Equiv. Ft (m)
INN 600N, INN 800N,
INN 1060N, INN
1350N
6”
(152 mm)
*140 ft.
(42.7 m)
10 ft.
(3.05 m)
5 ft.
(1.5 m)
* NOTE:
The maximum combined pressure drop of the exhaust and intake-air vents is 140 equivalent-
feet (42.7 m) for 6” (152 mm) pipe (all models). For the INN600N using 4” (102 mm) pipe the
maximum combined pressure drop of exhaust and intake-air vents is 80 (24.4 m) equivalent-
feet. See Section 3.4.