Monessen Hearth DLY18 Installation And Operating Instructions Manual page 8

GENERAL INSTALLATION INFORMATION
The following formula can be used to determine the maximum heater rating per the definition of un-
confined space:
Example: Refer to Figure 1, two (2) connecting rooms with an open area between, with the following
dimensions:
If there was a door between the two rooms the calculation would be based only on the room with the
heater:
If the area in which the heater may be operated is smaller than that defined as
an unconfined space or if the building is of unusually tight construction, pro-
vide adequate combustion and ventilation air by one of the methods described
in the National Fuel Gas Code, ANSI Z223.1, Section 5.3 or applicable local
codes.
8
L
2
L
1
Figure 1: Example of Large Room with 1/2 Wall
Divider
(L + L )FT x (W)FT x (H)FT
Btu/Hr =
1 2
L = 15 1/2'
1
L = 12'
2
W = 12'
H = 8'
(15 1/2 + 12) x (12) x (8)
50
(15 1/2 ) x (12) x (8)
50
Counter
Fireplace
H
W
x 1000
50
x 1000 = 52800 Btu/Hr
x 1000 = 29760 Btu/Hr