GENERAL
INDEECO Process Air Heaters are designed to provide
years of trouble free operation if properly installed and
maintained. Please read and follow these instructions for
installing and maintaining the heater.
INDEECO process air heaters are designed and intended
for installations in plenums or ducts to heat forced air in
industrial equipment and systems. A variety of designs and
sizes are available with outlet air temperatures up to
1200
°
F. Due to these high temperatures, the heater design
features must be closely matched to the application.
There are three types of heating elements:
•
Open Coil - a bare (electrically hot) resistance wire coil
•
Finned Tubular - a spiral finned metal sheathed element
•
Tubular – a tubular metal sheathed element.
Open coil elements
require clean, uniform airflow and can
only be mounted with the coils horizontal. They should not
be used where there could be contact with the coils by
personnel or electrically conductive material.
Finned tubular elements
can tolerate moisture and a
degree of non-uniform airflow. Finned tubular elements
should not be used where contaminants are likely to build
up between the fins.
Tubular elements
are universally applicable. Tubular and
finned tubular process air heaters can be mounted with the
elements either vertical or horizontal.
The heating elements are available in various watt density
ratings. Outlet temperature, watt density and airflow
velocity determine the surface temperature of the open coil,
tubular or finned tubular elements. Life of the heating
element is directly related to its surface temperature.
Follow the limitations of Table 1 for maximum watt densities
and minimum airflows. The watt density is shown on the
heater nameplate.
There are two types of heater frames:
•
A sheet metal frame for slip-in duct mounting is
standard for 250
°
F rated units (Figure 1).
•
A plug-type design with mounting plate is standard for
400
°
F through 1200
°
F rated units (Figures 2 & 3).
All open coil process air heaters, and the 250
°
F finned
tubular process air heaters, have top and bottom frames
that restrict the airflow to either horizontal or vertical, while
all other process air heaters can be used with any
perpendicular air flow direction.
Instructions for Industrial Control Panels are provided in
87-2000-83. A section on control methods is included.
Temperature regulating devices, temperature limiting
controls, and low flow controls are recommended for use
with process air heaters to control the heating process and
safeguard the heater from excessive temperatures that can
cause damage.
INSTALLATION
Handling and Storage
Care must be taken to avoid damage to the heater during
storage and handling. Protect the heater from weather
damage during storage if shipping packaging is not sealed.
It is recommended to store the heater in a cool dry area to
help prevent the heating elements or ceramic spacers from
drawing moisture.
Mechanical Instructions
Site Selection
Review the NEMA Type rating of the heater provided. Do
not install a heater in an area not consistent with its rating.
Allow at least three feet in front of the heater terminal box
for heater maintenance. Consideration should also be
given for heater removal clearance to allow heater
replacement.
Electric heaters are capable of developing high
temperatures. Therefore, extreme care should be taken to
avoid mounting heaters in an atmosphere containing
combustible gases, vapors, dusts, or fibers unless properly
marked as suitable for the condition.
If the duct or plenum is insulated, be sure that insulation
does not block airflow across the heating elements. Insure
that the airflow is uniform across the face of the heater to
INSTALLATION, OPERATING &
MAINTENANCE INSTRUCTIONS FOR
ELECTRIC PROCESS AIR HEATERS
CAUTION
INDEECO recommends installation be performed by
qualified personnel familiar with the National Electrical
Code and all local codes and standards. It is the
responsibility of the installer to verify the safety and
suitability of the installation
CAUTION
Failure to follow INDEECO recommendations could
result in premature failure and/or serious equipment
damage.
WARNING
Hazardous voltages are present in this equipment. Lock
out and tag the branch circuit disconnect switch before
working on this heater.
WARNING
DO NOT mount heaters in an atmosphere containing
combustible gases, vapors, dusts, or fibers.
