Chromalox CAB - Manual (Page 2)

GENERAL
WARNING: This heater is not intended for use in
hazardous atmospheres where flammable vapors,
gases, liquids or other combustible atmospheres are
present as defined in the National Electrical Code.
Failure to comply can result in explosion or fire.
1. Heat Construction Characteristics:
A. Finstrip ® elements of either rust resisting iron or chrome
steel sheath, and aluminized steel fins.
B. 14 gage cold rolled steel frame painted with a black pow-
der coat paint.
C. Internal electrical connections consist of buss bars and
jumper straps of either Mn-Ni or Monel.
D. Field wiring terminals of heavy duty 3/8” diameter bolts of
either brass (iron sheath units) or stainless steel (chrome
steel sheath units) with hardware are provided for field
wiring connections.
2. Maximum temperatures — Type CAB and CABB air duct
heaters can generally be used at the following maximum tem-
peratures provided the minimum air velocity is maintained
uniformly through the heater. Table 2 is based on the standard
unit of 26 watts per square inch. If unit watt density is lower,
higher temperatures can be achieved. If higher watt densities
are used, outlet air temperature should be lowered.
3. Several heaters may be mounted in tandem as long as proper
controls are used to limit the maximum temperature attained. See
pressure drop curve G112S1 for effect of mounting in tandem.
4. Overtemperature protection — A thermal cutout should be
installed at the exhaust side of the heater for protection against
low airflow conditions.
INSTALLATION
WARNING: Hazard of Electric Shock. Disconnect
all power before installing heater.
1. Install heater into desired location in air duct with terminals
on bottom.
2. For installation where the duct heater is larger than the duct-
work, the duct area must be increased by a sheet metal transi-
tion. The slope of the transition piece on the upstream side is
limited to 30˚ as indicated in Figure 2. On the leaving side, the
slope should not be more than 45˚.
3. Make sure ductwork is of sufficient strength to contain the
heater. Refer to Table 1 for heater weights. Consult your local
sheet metal contractor if in doubt.
4. Two holes 5/16-18 tapped are located on each side of the
heater for mounting.
5. Air velocity must be sufficient enough to prevent element fail-
ure. See Table 2 for guidelines.
6. For protection against accidental air stoppage, mount a ther-
mal cutout on the exhaust side of the heater.
7. Insert thermal cutout sensitive bulb through duct and attach to
heater case with mounting clips provided.
8. DANGER: Hazard of Fire. Since these heaters are capa-
ble of developing high temperatures, extreme care should be
taken to:
a. Avoid installing heaters in an atmosphere containing com-
bustible gases and vapors.
b. Avoid contact between heater and combustible material.
c. Keep combustible material far enough away to be free of
the effects of high temperatures.
Air Velocity Max. Outlet Air Temp. (˚F)
(Ft./Sec.) Iron Sheath Chrome Steel Sheath
4 — 200
9 90 330
16 220 440
Air
Flow
30˚
Max
30˚
45˚
45˚
Duct Heater
4 Ft. Min. 4 Ft. Min.
1.0
.9
.8
.7
.6
.5
.4
.3
.2
.1
.09
.08
.07
.06
.05
.04
.03
.02
.01
.009
.008
.007
.006
.005
.004
.003
.002
300 600 900 1200 1500 1800 2100
Triple Row of CAB
Double Row
Single Row
Velocity of Air F.P.M. (STD. Air)
Curve G112S1 - Resistance to Air Flow
Pressure Drop - In. of Water (LBS/In
2
= IN. of Water x 0.036)
Table 2
Figure 2