Chromalox S-RAD-2 User Manual
DATE
SALES
REFERENCE
DIVISION SECTION
Chromalox
®
(Supersedes PG422-1)
PG422-2
RAD
161-058066-001
SEPTEMBER, 2001
4
Type S-RAD
Electric Radiant Heater
© 2010 Chromalox, Inc.
Specifications
MOUNTING
Hazard of Fire. In the case of solvents of an explosive nature, ventilation air must be in sufficient volume to dilute the solvent vapor so that explosive
mixtures cannot occur. In order to comply with the
standards of safety required by the insurance companies, ventilation protection and other facilities
must be in accordance with National Fire Protection
Association Bulletin No. 86, entitled “Standard for
Class A Ovens and Furnaces”. This bulletin may be
obtained from the Association at 1 Batterymarch
Park, Quincy, MA 02269.
Length (In.)
Model Volts kW Overall Heated
S-RAD-2 120 or 240
0.95 24-3/8 16-1/2
S-RAD-2V 208 or 275
S-RAD-3 120 or 240
1.3 30-5/8 22-3/4
S-RAD-3V 208 or 275
S-RAD-4V 208 or 275
2.2 46-5/8 38-5/8
S-RAD-4 240 or 480
S-RAD-5V 208 or 275
3.0 61-3/8 53-3/8
S-RAD-5 240 or 480
S-RAD-6V 208 or 275
3.75 73-3/4 65-3/4
S-RAD-6 240 or 480
S-RAD-7V 208 or 275
4.4 85-3/4 77-3/4
S-RAD-7 240 or 480
Note: Please familiarize yourself with these instructions before attempting
to install or connect this Radiant Heater.
Before Installing
1. Open carton and remove heater at the place of installation.
Mounting clamps are in parts bag in carton.
2. Check nameplate volt and watt rating against your power sup-
ply voltage and heating requirements of your installation. This
nameplate is located on one end of the heater.
ELECTRIC SHOCK HAZARD. Disconnect all power
before installing or servicing heater. Failure to do
so could result in personal injury or property damage. Heater must be installed by a qualified person
in accordance with the National Electrical Code,
NFPA 70.
1. Clamps — Heaters are mounted by means of the mounting
clamp and
3
/8” bolt assembly which is used as shown in Figure
2. Clamp assembly may be attached to heater by sliding over
end or by snapping over top of extruded frame section at any
point along its length (see Figure 3). For proper heater support,
the maximum distance between clamps must not exceed 48”.
On extra-long heaters, more than two clamps are furnished.
2. Mounting Holes — When heaters are mounted adjacent to
each other in the same plane, note that distance between mounting holes on framing to support heaters will be 3
11
/16” minimum.
When heaters are not in the same plane, i.e., set at an angle to
one another, distance between mounting holes in framing will
be either greater or less than 3
11
/16”.
3. Framing — Where an extensive installation is being made, the
use of continuous slot metal framing manufactured by several
concerns will be of assistance in saving time and money. The
framing is reusable.
4. Reflector Spacer Sheets — Where heaters are not mounted
side by side (see Figure 4), reflector spacer sheets can be used
between heaters. These reflector spacer sheets and companion
reflectors consisting of an extruded aluminum housing with
reflector sheet and mounting clamps are available. Check factory.
5. Insulation — Where unusually high work temperatures are
encountered, it may be desirable to insulate backs of heaters
with high-temperature fibrous insulation. A suggested method
of accomplishing this is indicated in Figure 4.
6. Ventilation — Where solvents, water, etc. are being evaporat-
ed from work in process, it is necessary to provide substantial
quantities of ventilation air to carry away the resulting vapors.
Mounting Frame
Reflector
Spacer Sheet
Insulation
Figure 4
Figure 1 — Heater Parts and Dimensions
2 / "
15
16
2 / "
3
8
3 / "
11
16
Figure 3
Figure 2
WIRING
Hazard of Fire. In the case of solvents of an explosive nature, ventilation air must be in sufficient volume to dilute the solvent vapor so that explosive
mixtures cannot occur. In order to comply with the
standards of safety required by the insurance companies, ventilation protection and other facilities
must be in accordance with National Fire Protection
Association Bulletin No. 86, entitled “Standard for
Class A Ovens and Furnaces”. This bulletin may be
obtained from the Association at 1 Batterymarch
Park, Quincy, MA 02269.
Before energizing this heater:
1. Be sure all electrical connections are tightly made.
2. Be sure that all conductors are properly insulated, and that they
will not chafe at the heater wire entrance due to expansion and
contraction of the heating element.
3. Be sure that all terminal covers have been properly replaced,
and that secondary insulation bushings have not been omitted.
A. Controlling Radiant Intensity —
Standard Radiant Heaters are built to operate at 40 watts per sq.
inch on the element sheath. When it is desired to reduce radiant
intensity, one or more of the following methods may be used.
1. INPUT CONTROLLERS — These motor-driven cycling
devices can be used to vary heater output capacity from 4 to
100%. They are usualy connected in holding coil circuit of
magnetic contactors. See Chromalox Radiant Heater
Manual for further information regarding Input Controllers
and Contactors.
2. SOLID STATE THYRISTOR POWER CONTROLLERS — For best non-contact control of radiant
heat, a Series #6 Chromalox Thyristor Power Controller
with manual potentiometer setting is recommended. Truly
proportional output of from 0-100% can be easily dialed-in
to suit the particular product or process requirements. The
Series #6 panels are pre-engineered, pre-packaged assemblies in an enclosure with circuit disconnect provided and
ready for installation.
B. Maximum Ambient Temperatures —
Chromalox Radiant Heaters are not recommended for applications in ambient temperatures exceeding 450
O
F. Higher ambi-
ent temperatures mean shorter heater life.
Maximum work temperature in a given time depends on several factors: Reflectivity of work, specific heat of work, mass of
work, kW, input and losses from oven, and time of exposure.
As work temperature increases, the work loses heat by radiation and by convection to the surrounding ambient. Although it
is a general principle of Radiant Heater application, the work
temperature conventionally exceeds ambient temperature, in
cases where extremely high work temperatures are desired, it is
necessary to enclose the heaters in order to increase the ambient. If evaporation of a liquid is desired as a result of increasing work temperature, it is necessary to provide ventilation air
in order to carry away the evaporated liquid. Under carefully
engineered circumstances, a maximum work temperature of
600
O
F may be attained.
OPERATION
ELECTRIC SHOCK HAZARD. Any installation involving electric heaters must be performed by a qualified person and must be effectively grounded in
accordance with the National Electrical Code to
eliminate shock hazard.
1. Electrical connection to the Radiant Heater is made through
one opening tapped for
1
/2” connector. Opening is in the top of
the extruded heater housing, near the terminal end.
2. Wiring should be run in flexible or rigid metal conduit and
must be installed in accordance with local codes and the
National Electrical Code by a qualified person.
CAUTION: High temperatures will oxidize copper. Do not use copper wire in connecting this
heater. Insulated, nickel-plated copper wire is
recommended.
3. Access to Radiant Heater terminals is obtained by removing
the two screws in the terminal cover.
4. A sufficient length of this wire (not less than 12”) should be
used to extend from each heater terminal into a connection box
location where the temperature does not exceed 300
O
F.
5. Assemble terminal, screw and wire as shown in Figure 5.
6. Tighten the terminal screws securely with a screwdriver.
Note: Where circuit wiring is installed in locations of high
ambient temperature, conductors should be insulated in accordance with requirements for temperature and voltage.
7. SERIES CONNECTION of Radiant Heaters of equal volt
and watt rating is permitted in all line voltages up to 600 volts.
In making such series connections it is necessary to observe the
“right” (series-parallel) connection rather than the “wrong”
(parallel-series) connection both shown in Figure 6. If heaters
are connected according to the “wrong” illustration, failure of
any heater will cause progressive failure of other heaters still
operating.
8. DELTA CONNECTIONS — When heaters occur in multiples
of three, they may be connected to, and balanced across, threephase lines. The most commonly used connection is the Delta
connection illustrated in Figure 7.
Three phase Delta connections to minimize inductive effect in
conduits are made per this diagram. The rule: run all 3 three-phase
conductors in the same conduit as far as possible. For single-phase,
run only two conductors and follow the same rule.
Figure 6 — Series Connection
Figure 7 — Delta Connection
Figure 5 — Tightening Terminal Screws
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