Combustion Air Provision; Special Constderations - Weil-McLain GV90+ Installation And Start-Up Manual

GV90+ Series 2
OAS·FIRED WATER BOILER -
Boiler Manual
DIRECT EXHAUST - Boiler ro·om air openings
Combustion air provision
The GV%+ boiler can use inside air
if
no contaminants are prestnt in the
boiler space.
(If contaminants
art
likely
to be
pr~nt.
install the boiler
as a
d irect
vent appliance, using rhe appropriate •tent in.strucrtons in
this
manual.)
The boiler room must befitted with combustion
air
openings large enough
ro provide air for
all
appliances in rhe
room. USt the following
information
ro size the openings. Ensure the instaJI.ation complies
with
aU applicable
codes and standards.
\Vhert the GV90+ boiler shares a space with other appliances. the combus-
tion air openings mu.sr
bt
si7.td to handle the combined
r~uirt:mtnrs
of
all appliances in tbt space.
Sizing combustion air openings
Air openings provide for ventilation (as
wdl
as combustion air) ro prevent
O\'frheating of the boiler controls and boiler space. Air is also needed for
other appliances located in the same space.
Use Figure 60, page
50, selecting the appropriate
installation conditions.
IAWARt.tNGI
Air openings must be siud to handle all appliances and air
mowrs (exhaust fans, etc.) using rhe air supply.
The sizing given in Figure 60. page 50 is based on the National Fuel Gas
Code.
ANSI Z223.l,allowingadequate air openings for
gra\rity-venttd gas
appliances (Category I) in addition to thar
n~ed
for the GV90+ boiler.
The air openings recommended in Figure 60. page 50 will aJiow adequate
\rtntilation and combusrion air pro\rided the boiler room is nor subjttred
ro negative
pressu-~
due to exhausr f.ms or other mechanical vmtilation
devices.
Refer ro the National Fuel Gas Code for dealing wirh other conditions.
Free area - k>uver a llowan ce
The
free area of openings means the area
after reductlon for any Installed
louvers
or grilles. Be sure ro consider this reduction when siting the air
openings.
Part number 550-14-2-783/1012
Special considerations
Tight constnoctlon
ANSI Z223. 1 defines unusuaH)• right construction
where:
I.
VYalls and ceilings exposed to the outside atmo-
sphere have a continuous water vapor rrtarder
with
a raring of I perm or less with openings gasktred,
and .. ,
2. '"'eather-stripping has been added on openable
windO't\fS and doors. and .. .
3. Caulking or sealanrs are applied ro are:as such as
joinrs around windows and door frames, betw~n
sole plates and floors, between wall-ceiling joints,
between wall panels, at
pen~rations
for plumbing,
.electrical, and
gas
lines, and in orher openings.
For buildings with such construction, provide air
openings into the building from outside, sized per the
appropriate case in Figurt 60, page 50 if appliances art
to use inside air for combustion and ventilation.
Exhaust f an s and air movers
The appliance space must ne\·er be under a negative
pressure unless all appliances are installed as airect
vent. Always provide air openings sized not only to
the dimensions required for the lifing rate of
all
appli-
ances. but aJso to handle the air mO\rtment rate of the
exhausr fans or air movers using air from the building
or space.
Motorized air dampers
If the
air
openings ace
fitted
with motorized dampers,
e-lectrically interlock the damper to:
iPrevent the boiler from
firing
if the damper is not
fully~.
Shut the boiler down should the damptr close dur-
i ng boiler Optration.
To accomplish this interlock, wire an
Isolated
contact
(proving the damper Optn) in series with the thermo-
stat input ro the boiJer. The boiler will not start if this
conracr is Optn, and will shut down should it open
during operation.
49