LAARS Mighty Therm LO-NOx PH (Sizes 250/400) - Install and Operating Manual - Manual (Page 9)

Mighty Therm LO-NOx Hydronic Boiler Page 9
Table 2 ). Laars does not recommend indoor
installations that do not provide combustion air from
outside the building.
Boiler rooms which are confined spaces require
two permanent air supply openings: one within 12
inches (30.5 cm) of the ceiling, the other within 12
inches (30.5 cm) of the floor.
NOTE: Check with louver manufacturers for net free
area of louvers. If screens or louvers are installed, add
50 percent for each screen/louver to the net free area.
Check the latest edition of ANSI Z223.1 or in Canada
CSA B149 and all local codes applicable to
combustion air.
2.4.1 Outdoor Air Supply
When combustion air comes directly through an
outside wall, each opening must have a minimum free
area of at least one square inch for each 4,000 BTU/h
input of the total input rating of all appliances in the
enclosed area. (In Canada, refer to CSA B149.1)
2.4.2 Indoor Air Supply
Confined and non-confined areas have different
requirements for installation. Check the latest edition
of ANSI Z223.1 or in Canada CSA B149 and all local
codes applicable to combustion air.
2.4.3 Exhaust Fans or Vents
Any equipment which uses air or removes air
from the boiler room can use up the combustion air
supply or reverse the natural draft action of the venting
system. This could cause flue products to build up in
the boiler room. More air must be supplied to make up
for the decrease.
2.5 Venting (Category I)
2.5.1 General Information
When installed indoors, the drafthood must be
connected to a venting system. The venting system
must be installed by a qualified installer and in
accordance with the latest edition of ANSI Z223.1. In
Canada, the installation must be in accordance with
CSA B149.1, and any local codes that apply.
The vent pipe must have a listed vent cap, and
extend at least 2 feet (0.6 m) above any object within a
10 foot (3.0 m) radius.
NOTE: Do not use sheet metal screws at the snap
lock joints of Type B double-wall gas vents.
Do not weld or bolt the vent pipe to the boiler
drafthood. The weight of the stack must not rest on the
boiler. The drafthood and boiler top must be easily
removable for normal boiler service and inspection.
Table 2. Air Openings to Outside.
Required Net Free Opening Area
Directly from Outside
At Top At Bottom
Model in. 2 cm 2 in. 2 cm 2
250 63 406 63 406
400 100 645 100 645
Note: For screens or louvers, add 50%.
Figure 21. Indoor Installation and Venting.
Notes:
1.
The drafthood must sit directly on top of the heater
as shown and must not be altered in any manner.
2. An Underwriters' Laboratories listed vent cap is re-
quired to eliminate downdraft and allow the heater
to function properly.
3. Use approved roof fitting.
Vent terminated at
least 2 ft. (61cm)
above any
object within
10 ft. (3.0m)
10 ft.
(3.0m)
2 ft. (61cm)
Listed Vent
Cap
Storm Collar
Roof Jack
Drafthood
1/4 in. (0.6cm)
Minimum Pitch
Per Foot of
Horizontal Pipe
Figure 20. Base for Outdoor Installation.
LAARS
UNIT
(Side View)
123456789012345678901234567890121234567890123456789012345678901212345
123456789012345678901234567890121234567890123456789012345678901212345
123456789012345678901234567890121234567890123456789012345678901212345
123456789012345678901234567890121234567890123456789012345678901212345
123456789012345678901234567890121234567890123456789012345678901212345
12345678901234567890123
12345678901234567890123
12345678901234567890123
Base For Outdoor Unit
Adequate
Air Supply
To Room
Top and
Bottom
5 ft.
min.
(1.5m)
OUT OF
PRODUCTION