BOCK EzFit EZ 75-76N Інструкція з експлуатації - Сторінка 5
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Друкувати сторінкуSECTION III: PRE-INSTALLATION (cont .)
NOTE: Locate the heater so it is not subject to physical damage from moving vehicles or
flooding. Do not locate the water heater in a room where swimming pool chemicals or large
quantities of water softener salt are kept. Installing a water heater
in this environment will result in premature failure of tank and
burner components due to corrosion caused by these elements
diffusing into the air.
DO NOT INSTALL THE WATER HEATER ON COMBUSTIBLE
FLOORING. Place on noncombustible flooring and maintain
clearances prescribed by this manufacturer and per code NFPA 54.
If the water heater must be located on combustible flooring it must
be raised off the floor with a layer of 4'' concrete block laid so the
air holes are aligned as shown in Figure 2. Consult with local code
Figure 2
officials before using this method. Please consult local codes, NFPA
54 and/or contact Bock Water Heaters with questions concerning
proper flooring materials. Leave adequate room for periodic maintenance of heater and burner.
The water heater should be placed as near to the chimney as practical in order to keep vent
connector length to a minimum. Consult National Fuel Gas Code for proper vent configuration.
Minimum clearance to combustible construction is: SIDES 6"; BACK 6"; FRONT 24";
DRAFT HOOD; 18". The installation of this water heater must conform with local
codes and ordinances. In the absence of local codes, the installation must comply
with the National Fire Protection Association (NFPA 54) Code.
COMBUSTION AND VENTILATION AIR
The water heater must be installed in a location with an adequate air supply for combustion,
ventilation and draft control. Unsafe levels of carbon monoxide (CO), condensation and
sooting may result if the room does not have an adequate air supply. See "National Fuel Gas
Code (NFPA 54)" or the discussions of "Unconfined Space" and "Confined Space" below. Poor
ventilation will also result in hot spots around the heater. Temperatures over 90°F near the
water heater generally indicate a lack of ventilation.
UNCONFINED SPACE
Unconfined space is defined by NFPA 54 as a space with a volume greater than 50 cubic feet
(during typical use) per 1000 BTUH of the total combined input of all fuel burning appliances
in the space. Rooms leading directly to the installation space through doors that cannot
be closed can be considered part of the space. Exception: Buildings with full vapor barriers,
tight doors and windows or air infiltration rates of less than 0.35 air changes per hour will be
considered a confined space and require additional air supplies.
CONFINED SPACE
Confined space is defined by NFPA 54 as a space with a volume less than 50 cubic feet (during
typical use) per 1000 BTUH of the total combined input of all fuel burning appliances in the
space. Buildings or rooms of unusually tight construction are also considered a confined space.
See "Unconfined Space: Exception".
When installing fuel burning appliances in a confined space, air must be supplied to that
space from either inside or outside of the building as conditions allow.
A. Inside Air Supply: A confined space shall be provided with two permanent openings;
one within 12 inches of the top and one within 12 inches of the bottom of the enclosure.
These openings shall lead directly to room(s) of sufficient volume so that the combined
volume of all the space meets the criteria for unconfined space. Each opening shall have a
minimum free area of 1 square inch per 1000 Btu/hr of the combined total input of all fuel
burning appliances in the space. Each opening shall have an area of not less than 100 square
inches or a minimum dimension of not less than 3 inches.
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Atmospheric Gas
SECTION III: PRE-INSTALLATION (cont .)
CONFINED SPACE (CONT.)
B. Outside Air Supply: Confined spaces shall be provided with two permanent openings;
one within 12 inches of the top and one within 12 inches of the bottom of the enclosure.
These openings shall communicate directly, or by ducts, with the outdoors or spaces that
communicate with the outdoors.
1.) Leading directly to the outside or through vertical ducts: Each opening shall have a
minimum free area of one square inch per 4000 Btu/hr of total input rating of all equipment
in the enclosure.
2.) Leading to outside through horizontal ducts: Each opening shall have a minimum free
area of one square inch per 2000 Btu/hr of total input rating of all equipment in the enclosure.
Note: All ducts shall have the same cross sectional area as the free area of each opening to
which they connect. The minimum dimensions of all ducts shall not be less than three inches.
Powered combustion air supplies are also commercially available and may be used.
LOUVERS & GRILLES
In calculating the free area of an opening, consideration must be given to the blocking effects
of louvers or grilles protecting the opening. Any screens used must be no finer than
mesh. If the free area of a louver or grille is known, this should be used in calculating the size
of opening required. If free area is unknown, it may be assumed that wood louvers will have
20 to 25% free area and metal louvers and grilles will have 60 to 75% free area. Louvers and
grilles should be fixed in the open position or interlocked with the equipment so that they
open automatically during equipment operation.
VENTING
The water heater shall be located as close to the chimney as practical. Long lateral runs will
result in intermittent combustion problems and unsafe operating conditions. Total vent
height should be a minimum of 6 feet. Shorter vent heights could result in unstable draft and
nuisance lock outs.
The venting system should be sized according to National Fuel Gas Code: NFPA 54/ANSI
Z223.1 (most recent edition) using the "Natural" column. If you do not have a copy of this
code one can be obtained at www.NFPA.org for a nominal fee. Copies of the NFPA venting
tables are also reprinted in the Bock Engineering Manual available from your Bock Represen-
tative or by download from www.bockwaterheaters.com. Note: Do not reduce vent size more
than one size smaller than the vent connector supplied with the heater. If vent size must be
reduced one size, use full size vent connectors on the vent hood and reduce vent size as far
from the water heater as practical. B vent, L vent or multi-fuel venting may be used. Vent
tables supplied by the vent manufacturer may also be used in sizing the vent system.
Venting system must be capable of producing –0.02" WC (inches of water column) draft
minimum. If draft of –0.02" WC cannot be produced with an existing vent system, a draft
inducer may be required. Installations common vented with large vent hood equipped
appliances such as heating boilers may require vent dampers on the heating boiler connectors
for proper vent operation during no-heating season.
Check the building for items that can cause severe negative pressure problems such as large
exhaust fans. If these devices are installed in the same building check for their effect on draft
and combustion. All fuel burning appliances must be isolated from the effects of these devices
to operate properly. Failure to address this issue will result in unsafe operation and shorten
appliance life spans.
Atmospheric Gas
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