Desa CHAM55N Safety Information And Installation Manual page 10

INSTALLATION
Continued
Btu Input
Description
Natural Gas
18" Dual
Burner
FUEL INLET PRESSURE
SPECIFICATIONS (W.C.)
Min.
NG 5.5" (140 mm)
LP 11" (80 mm)
BURNER ORIFICE
Natural
Log
Size
In.
18" 0.10
Figure 9 - Technical Information Charts
SIzING PROPANE/LP SUPPLY TANK
CAUTION: For propane/LP
gas, make sure external regula-
tor has been installed between
propane/LP supply and heater.
See guidelines under Connect-
ing Propane/LP Supply Tank.
The models CHAM45P, FC45AP and VC45AP
are supplied with a two stage, propane/LP regu-
lator and 10 foot (3 m) hose assembly ready for
connection to 3/8" flare fitting at inlet of manual
control valve.
The propane/LP regulator is factory set at 11"
(280 mm) w.c. and can be connected to a properly
sized and approved propane/LP supply tank. This
supply tank can be purchased from your propane/
LP or builder supplier.
The propane/LP cylinder used must be constructed
and marked as (DOT or CAN/CSA B339) ap-
proved for vapor withdrawal and equipped with a
safety relief type ON/OFF valve with a protective
collar. The propane/LP cylinder must be sized
according to the input rate and expected ambient
temperature of fuel in container.
The first table (Figure 10) indicates the vaporiza-
tion rate of propane/LP fuel at various Btu/Hr input
rates for a range of cylinder sizes and ambient fuel
temperatures. An undersized or under filled pro-
10
Btu Input
Propane Gas
55,000 45,000
Max.
10.5" (67 mm)
1" (0 mm)
Propane/LP
Num. In.
1 0.07
www.desatech.com
pane/LP tank, when evacuating at lower outdoor
temperatures, can cause a condition known as "va-
por lock" to occur. Vapor lock prevents vaporized
fuel from reaching the burner system.
It is important to use a cylinder size based on an
input rate higher than 45,000 Btu/Hr at the lowest
expected outdoor ambient temperature to insure
vaporization of fuel.
The second table (Figure 11) indicates the maxi-
mum Btu content of a full cylinder and can be used
to calculate the approximate operating hours.
Example:
20 pounds propane/LP = 431,200 Btu's
431,200 Btu ÷ 45,000 Btu/Hr = 9.5 Hours
Actual operating hours may vary depending on
outdoor temperature and fill quality of tank.
Num.
49
Pounds of
propane/LP
in cylinder
100
90
80
70
60
50
40
0
0
10
Figure 10 - Vaporization Rate (per 100
Cylinder Size
14.1 oz (0.4 kg)
16.4 oz (0.5 kg)
5 lb (. kg)
10 lb (4.5 kg)
0 lb (9.1 kg)
100 lb (45 kg)
50 gal (946 L)
500 gal (1900 L)
1000 gal (790 L)
Figure 11 - Maximum Btu Content
Max. Continuous Draw in
BTU per hour at various
temperatures
0° F 0° F
(-17.8° C) (-6.7° C)
11,000 167,000 14,000
104,000 15,000 00,000
94,000 17,000 180,000
8,000 1,000 160,000
75,000 109,000 140,000
64,000 94,000
55,000 79,000
45,000 66,000
6,000 51,000
8,000 8,000
pound cylinder)
BTU Content
19,000
,100
107,800
15,600
41,00
,156,000
,875,000
45,750,000
91,500,000
40° F
(4.4° C)
15,000
105,000
85,000
68,000
49,000
901918-01J