Lochinvar EW 150, Designer'S Manual

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4
L o c h i n v a r
D E S I G N E R
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S G U I D E E F F I C I E N C Y
+
W A T E R H E A T E R
6 1 5 - 8 8 9 - 8 9 0 0
The equipment room MUST be provided with
properly sized openings to assure adequate
combustion air and proper ventilation, when
the unit is installed with conventional venting or
sidewall venting.
If air is taken directly from outside the building with
no duct, provide two permanent openings:
A.
Combustion air opening, with a
minimum free area of one square inch per
4000 Btu/hr input (5.5 cm
2
per kW).
This opening MUST be located within 12
”
(30 cm) of the bottom of the enclosure.
B.
Ventilation air opening, with a minimum
free area of one square inch per 4000
Btu/hr input (5.5 cm
2
per kW).
This opening MUST be located within 12
”
(30 cm) of the top of the enclosure.
If combustion and ventilation air is taken from the
outdoors using a duct to deliver the air to the
mechanical room, each of the two openings
should be sized based on a minimum free
area of one square inch per 2000 Btu/hr
(11 cm
2
per kW).
If air is taken from another interior space,
each
of the two openings specified above should
have a net free area of one square inch per
1000 Btu/hr (22 cm 2 per kW) input, but
not less than 100 square inches (645 cm
2
).
Lochinvar
2.
(FIG. 4) COMBUSTION AIR FROM AN
INTERIOR SPACE
(FIG. 3) COMBUSTION AIR THROUGH
DUCTWORK
3.
(FIG. 2) COMBUSTION AIR DIRECT FROM
OUTSIDE
1.
EXAMPLE OF
SIZING FOR
COMBUSTION
& VENTILATION
AIR OPENINGS
(WATER HEATER
WITH 300,000
BTU/HR INPUT):
When combustion and
ventilated air is taken
from directly outside the
building (FIG. 2), divide
the total BTU’s by 4,000.
This yields 75 sq.in. of
“Free Area” without
restriction.
(300,000/4,000 =
75 sq.in.)
Since the air opening is
50% closed due to
screens and louvers, the
total opening MUST be
multiplied by 2.
(75 sq.in. x 2 =
150 sq.in.)
This project requires one
Ventilation Air Opening
of 150 square inches
with louver dimensions
of 12” x 15”= 180
sq.in. and one
Combustion Air Opening
of 150 square inches
with louver dimensions
of 12” x 15”.