®
Chromalox
SERVICE REFERENCE
Installation Instructions
DIVISION
SALES
4
SECTION GEN
REFERENCE (Supersedes POO400-6) POO400-7
161-048339-001
DATE
DECEMBER, 2006
®
General Recommendations on the Use of Chromalox
Electric Heating Elements for Clamp-On,
Oven and Air Duct Heating
CHROMALOX ELECTRIC HEATING ELEMENTS FOR CLAMP-ON
The electric heating element(s) supplied herein are ruggedly
constructed and if properly installed, operated and maintained, are
designed for long life and dependable, trouble-free service.
The following units are generally used in these applications:
Tubular, Strip, Ring, Fin-Tubular and Fin-Strip
GENERAL
Users should install adequate controls and safety
devices with their electric heating equipment.
Where the consequences of failure may be severe,
back-up controls are essential, including GFCI
(Ground Fault Circuit Interrupters). Although the
safety of the installation is the responsibility of the
user, Chromalox will assist in identifying equipment
options.
FIRE HAZARD. Since heaters are capable of devel-
oping high temperatures, extreme care should be
taken to:
A. Avoid mounting heaters in an atmosphere containing com-
bustible gases and vapors.
B. Avoid contact between heaters and combustible materials.
C. Keep combustible materials far enough away to be free of the
effects of high temperatures.
INSTALLATION
more that one clamp is used, tighten clamps to avoid bowing of
heater, poor heat transfer and possible premature failure. Leave
1/2” space between heater ends clamped in line for expansion.
Do not use mounting tabs for clamping to surface.
ELECTRIC SHOCK HAZARD. Disconnect all power
before installing or servicing heater. Failure to do
so could result in personal injury or property dam-
age. Heater must be installed by a qualified person
in accordance with the National Electrical Code,
NFPA 70.
2. When strips are clamped to tank bottom for melting paraffin,
waxes, asphalt, greases, etc., one or two strips should be
clamped vertically to the tank side extending above the liquid
level. This is necessary to open a passage to the tank surface for
the initially melted material, and prevent build-up of pressure.
High heating efficiency, low sheath temperatures and long
heater life result when electric heaters are properly installed.
3. Clamp ring heaters to smooth metal surface. Use cast iron utility
clamps with 1/4” MONEL® or stainless steel studs. Retighten
following initial heat-up.
INSTALLATION – CLAMP-ON
1. Clamp strip heaters securely, along their entire length, to
smooth metal surface. Use utility clamps spaced 5” apart and
5/16” stainless steel studs or oversized steel studs for clamping.
Retighten following initial heat-up. Allow for expansion. When
4. Tubular heaters are clamped the same as strips against the metal
surface.
5. Allow a minimum of 1” air space between heaters and insula-
tion.
© 2010 Chromalox, Inc.
CHROMALOX ELECTRIC HEATING ELEMENTS FOR OVEN HEATING – AIR DUCTS
The electric heating element(s) supplied herein are ruggedly con-
structed and if properly installed, operated and maintained, are
designed for long life and dependable, trouble-free service.
GENERAL
Temperature regulating and temperature limiting controls are
recommended to be used with electric heaters to control the heating
process and safeguard the electric heaters from excessive tempera-
FIRE HAZARD. Since heaters are capable of devel-
tures that can damage heaters.
oping high temperatures, extreme care should be
taken to:
A. Avoid mounting heaters in an atmosphere containing com-
bustible gases and vapors.
B. Avoid contact between heaters and combustible materials.
C. Keep combustible materials far enough away to be free of the
effects of high temperatures.
INSTALLATION
4. Mount strips on edge in horizontal installation across the bottom
and along the sides on the oven, allowing 3” minimum air space
between the heaters and the bottom of the oven and 1” from the
ELECTRIC SHOCK HAZARD. Disconnect all power
oven wall to allow for proper circulation of heated air. For large
before installing or servicing heater. Failure to do
ovens, allow a 6” minimum clearance.
so could result in personal injury or property dam-
5. In horizontal mounting, install a protective screen or grill above
age. Heater must be installed by a qualified person
in accordance with the National Electrical Code,
NFPA 70.
the strips at the bottom of the oven.
6. Support long iron sheathed strips on 36” centers and chrome
steel sheathed strips on 24” centers to prevent sagging.
High heating efficiency, low sheath temperatures and long
heater life result when electric heaters are properly installed.
INSTALLATION – AIR DUCTS
1. Locate protective thermostat on downstream side of heaters near
the top of the duct and close to the heated portion of the heaters.
2. Mount heaters with terminals at the duct bottom to prevent over-
heating.
3. Where condensation, spray, oil or fumes are present use seam-
less finstrips, type SSEF, with the terminals placed outside of
the air duct.
4. As a safety feature in advent of abnormal temperatures, it is sug-
gested to use a thermal cutout in conjunction with thermostatic
control.
INSTALLATION – OVEN HEATING
1. When mounting the strip heaters vertically, locate the terminals
at the bottom or cooler parts of the oven. Allow for expansion
and contraction by loosely bolting the top mounting tab. Secure
the bottom tab firmly.
2. In a forced air system, the width of the strip should be parallel to
the direction of air flow.
3. For horizontal installation of strips, the tab on the terminal end
should be firmly connected and the opposite end loosely con-
nected to allow for expansion and contraction.
WIRING
1. Electric wiring to heating elements must be installed in accor-
dance with National Electrical Code or local electrical codes by
a qualified person.
ELECTRIC SHOCK HAZARD. Any installation involv-
ing electric heaters must be performed by a quali-
fied person and must be effectively grounded in
accordance with the National Electrical Code to
eliminate shock hazard.
2. Temperatures at heater terminals may require use of high-tem-
perature wire. Check factory for recommendations.
3
CHROMALOX ELECTRIC HEATING ELEMENTS FOR OVEN HEATING – AIR DUCTS (cont’d)
GENERAL INFORMATION
1. Strips of equal wattage and voltage can be series connected for
a maximum of 480 volts. If a higher voltage (600 volt max.) is
necessary use the same series connections and use secondary
insulation bushings.
2. Use iron or steel sheathed heaters for temperatures up to 750˚F
maximum sheath temperature. Use chrome steel sheathed strips
for temperatures up to 1200˚F maximum sheath temperature.
Use alloy or Inconel® sheathed tubular heaters for temperatures
up to 1500˚F maximum sheath temperature. The sheath temper-
ature is the highest temperature on the surface of the heater
when operating.
3. Do not bend or form strips.
4. Use manganese nickel wire or alloy bus bar for making electri-
cal connections where temperatures are above 350˚F. Insulated
copper wire may be used in the cooler region.
5. Terminals should always be in the coolest part of the oven. If
oven temperature is over 800˚F the terminals should be placed
outside the oven if possible. If not possible, weld electrical con-
nections to heater terminals. Protect terminals from welding
flux.
6. Tubulars are to be mounted the same as strips and supported on
24” centers.
MAINTENANCE
1. Periodically clean terminals of dust and corrosion to maintain
good electrical connections and to permit rapid heat dissipation.
Use airblast and be careful to avoid damage to mica insulation.
2. Check for loose terminal connections.
ELECTRIC SHOCK HAZARD. Disconnect all power
before installing or servicing heater. Failure to do
so could result in personal injury or property dam-
age. Heater must be installed by a qualified per-
son in accordance with the National Electrical
Code, NFPA 70.
Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
2150 N. RULON WHITE BLVD., OGDEN, UT 84404
Phone: 1-800-368-2493
|