ELECTRIC DUCT
H
EATERS
INSTALLATION, OPERATION
AND
MAINTENANCE MANUAL
Stock ID: IOM-EDH
Reprinted June, 2001
©2001 Environmental Technologies, Inc.
Largo, FL • Part No. PX-00-0141
ELECTRIC DUCT HEATER • I.O.M.
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Electric Duct Heater IOM • ©June, 2001 • Environmental Technologies, Inc.
TABLE OF CONTENTS
DESCRIPTION PAGE
Pre Start-Up ........................................................................................................................................3
Receiving and Inspection ....................................................................................................................3
Unit Placement ...................................................................................................................................3
Clearance ............................................................................................................................................3
Electric Heater Warning Labels ...........................................................................................................4
Minimum Air Velocities
Open Coil Construction.................................................................................................................5
Finned Tubular Construction .........................................................................................................5
Heater Installation Instructions
Side Slip-In ....................................................................................................................................6
Insulated .......................................................................................................................................6
Flanged .........................................................................................................................................7
Round Duct...................................................................................................................................7
Remote Control Panel ...................................................................................................................7
Minimum Wire Gauge ........................................................................................................................8
Field Wiring ........................................................................................................................................8
Preventative Maintenance...................................................................................................................8
Ampere Reading per kW.....................................................................................................................9
Airflow Switch Probe Reversal ............................................................................................................9
Troubleshooting Guide .......................................................................................................................9
Sample Submittal Wiring Diagrams ...................................................................................................10
Troubleshooting Guide, Proportional Heat Control (SSR)...................................................................12
Troubleshooting Guide, Vernier Heat Control....................................................................................14
Replacement Parts .............................................................................................................................14
Important Safety Precautions......................................................................................................15
I.O.M. • ELECTRIC DUCT HEATER
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Environmental Technologies, Inc. •©June, 2001 • Electric Duct Heater IOM
PRE START-UP
WARNING: Improper installation, adjustments, alterations, service or maintenance can cause injury and
property damage, as well as possible voiding of factory warranty. For assistance or additional
information, consult a qualified contractor and your local ENVIRO-TEC
®
representative.
RECEIVING AND INSPECTING
• Thoroughly examine the exterior and interior of all units for transportation damage. If damage is found,
immediately file a claim with the carrier. Note the damage on the bill of lading when signing for the shipment.
• Check the bill of lading to verify that all items shown (including loose items) have been received. Notify the
ENVIRO-TEC
®
representative of any shortages or items shipped in error.
• Do not handle the unit's heating elements, as permanent damage may occur.
UNIT PLACEMENT
CAUTION: Never energize a heater without proper airflow.
• Install ductwork to comply with ASHRAE Fundamentals Handbook, SMACNA, NFPA 90A and local code.
• ENVIRO-TEC
®
duct heaters are manufactured under ETL File #549556, or ETLC File #548276, and must be installed
in compliance with all National and Local Codes. Improper installation of these units can result in the removal of
the Listing Label and/or voiding of the Warranty. Airflow and airflow patterns are important to the operation and
life of the heater (see airflow graphs on page 5). Proper airflow will also prevent nuisance tripping of
the thermal safety devices.
• Open coil duct heaters are certified for horizontal airflow in either direction, or for vertical up airflow. Some
heaters may contain position sensitive devices (mercury contactors or Solid State Relays) and can only be mounted in their specific designed configuration. These heaters will be marked with specified mounting configuration
labels. Do not install a slip-in or flanged heater intended for side mount on the top or bottom of horizontal duct.
Do not install a heater marked for horizontal airflow in vertical duct or a vertical heater in horizontal duct.
• When an airflow switch is used as a fan interlock, the heater will contain an air pick-up probe. The pick-up probe
contains a directional arrow and may be rotated on horizontal units only (see figure 6 on page 9).
• Install units in a section of duct with uniform air velocity across the full face area of the duct. For best
performance, heaters should be mounted a minimum of 4 feet downstream of a heat pump, transition, air
conditioner or other obstructions in the duct work. Per NEC Article 424-59, turning vanes, pressure plates or other
devices may be used to ensure even air distribution if mounted less than 4 feet. Duct heaters for internally
insulated ducts will be designed to accommodate insulation thickness.
CLEARANCE
• All electric heat units are ETL listed for zero clearance to combustibles. Therefore, the element frame height will
be 1" less on uninsulated duct and the width will be 1/2" less.
• All electrical panels must have 36" working space in front of panel to meet NATIONAL ELECTRICAL CODE;
however, local inspectors may wave this requirement if the hinged cover has a 90° free swing.
CAUTION
HAZARD OF ELECTRIC SHOCK.
MORE THAN ONE DISCONNECT
SWITCH MAY BE REQUIRED TO
DE-ENERGIZE THE EQUIPMENT
FOR SERVICING.
ELECTRIC DUCT HEATER • I.O.M.
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Electric Duct Heater IOM • ©June, 2001 • Environmental Technologies, Inc.
CAUTION
DISCONNECT THE ELECTRIC
POWER BEFORE SERVICING.
ATTENTION:
DECONNECTER DU CIRCUIT
D’ALIMENTATION ELECTRIQUE
AVANT L’ENTRETIEN.
CAUTION
ELECTRICAL HAZARD
AFTER INSTALLATION AND BEFORE ENERGIZING
THIS UNIT, CHECK ALL ELECTRICAL CONNECTIONS
FOR TIGHTNESS.
ALL ELECTRICAL CONNECTIONS SHOULD THEN BE
PERIODICALLY CHECKED FOR TIGHTNESS.
ALTERNATION OF INTERNAL COMPONENTS OR
WIRING WILL FURTHER RESULT IN REMOVAL OF THE
PRODUCT LISTING AND VOIDING OF ALL
WARRANTIES.
ELECTRIC HEAT WARNING LABELS
The labels shown below are located on the door of all electric heat units in compliance
with our ETL listings to UL 1996 and CAN/CSA C22.2 No. 155. Adherence to these warning
labels prevents possible injury or damage to equipment and/or property.
Disconnect Hazard Labels
Ensure that all power has been disconnected prior to servicing equipment.
Start-Up Caution Label
Tighten all wiring lugs and terminals prior to connecting power to the unit,
as they may loosen during transportation.
I.O.M. • ELECTRIC DUCT HEATER
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Environmental Technologies, Inc. •©June, 2001 • Electric Duct Heater IOM
MINIMUM AIR VELOCITIES
0
200
400
600
800
1000
1200
1400
1600
0 2 4 6 8 10 12 14 16 18 20 22 24
KW/SQ FT.
VELOCITY (FPM)
ENTERING AIR (Deg. F)
806040
25
10
0
OPEN COIL CONSTRUCTION
100
200
300
400
500
600
700
800
900
1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
KW/SQ FT.
15.5 Maximum Kw/Sq. Ft.
FPM
304.8
274.2
243.6
213.0
182.4
152.4
121.8
91.2
60.6
30.0
M/MIN.
HORIZONTAL AIRFLOW
VERTICAL AIRFLOW
F
INNED TUBULAR CONSTRUCTION
VELOCITY
INLET AIR TEMPERATURE
77°F, 25°C
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