9
Fig. 6: Minimum Clearances from Combustible
Surfaces – Indoor and Outdoor Installations
installed on the air filter intake at the rear of the unit
during installation. The intake elbow
MUST
be orient-
ed with the open end facing downward.
Heaters must not be installed under an overhang
unless clearances are in accordance with local instal-
lation codes and the requirements of the gas supplier.
Three sides must be open in the area under the over-
hang. Roof water drainage must be diverted away
from heaters installed under overhangs.
Table D: Clearances – Outdoor Installations
the heater to be serviced in its installed location with-
out movement or removal of the heater.
Service clearances less than the minimum may
require removal of the heater to service either the heat
exchanger or the burner components. In either case,
the heater must be installed in a manner that will
enable the heater to be serviced without removing any
structure around the heater.
Outdoor Installations
Outdoor installation
REQUIRES
the use of the com-
bustion air intake elbow. The intake elbow must be
ordered when ordering the unit and is shipped loose
for field installation. The intake air elbow
MUST
be
Combustion and Ventilation Air
Indoor Units
This heater must be supplied with sufficient quantities
of non-contaminated air to support proper combustion
and equipment ventilation. Combustion air can be sup-
plied via conventional means where combustion air is
drawn from the area immediately surrounding the
heater, or via direct vent, where combustion air is
drawn directly from outside. All installations must com-
ply with the requirements of the NFGC (U.S.) and
B149 (Canada), and all local codes.
NOTE:
Use of this heater in construction areas
where fine particulate matter, such as concrete or
dry-wall dust, is present may result in damage to the
heater that is not covered by the warranty. If
operated in a construction environment, a clean
source of combustion air must be provided directly to
the heater.
Heater
Side
Min. Clearance
from Combustible
Surfaces
Minimum
Service
Clearance
Rear
12”
24”
Front
Open
24”
Right Side
1”
1”
Left Side
1”
1”
Top
Unobstructed
10”
Vent
Termination
12”
12”
CAUTION:
Combustion air must not be
contaminated by corrosive chemical fumes which
can cause non-warrantied damage to the heater.
(See the Appendix.)
NOTE:
It is recommended that the intake vent be
insulated to minimize sweating.
Summary of Contents for MVB 504A
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