RenewAire EK Series User manual
EK Series shown
EK Series for Commercial Indoor Applications
EK SERIES Electric Duct Heater
Installation, Operation and Maintenance Manual
1.800.627.44992
EK-Series Electric Duct Heater
ACCESSORY
WARNING
Arc flash and electric shock hazard
Arc flash and electric shock hazard. Disconnect all electric
power supplies, verify with a voltmeter that electric power
is off and wear protective equipment per NFPA 70E before
working within electric control enclosure. Failure to comply can
cause serious injury or death.
Customer must provide earth ground to heater, per NEC, CEC
and local codes, as applicable.
Before proceeding with installation, read all instructions, veri-
fying that all the parts are included and check the nameplate to
be sure the voltage matches available utility power.
The line side of the disconnect switch contains live high-volt-
age.
The only way to ensure that there is NO voltage inside the
heater is to install and open a remote disconnect switch and
verify that power is off with a volt meter. Refer to unit electrical
schematic. Follow all local codes.
CAUTION
CAUTION
Risk of electric shock or equipment damage
Whenever electrical wiring is connected, disconnected or
changed, the power supply to the heater and its controls must
be disconnected. Lock and tag the disconnect switch or circuit
breaker to prevent accidental reconnection of electric power.
Risk of contact with HOT SURFACES
This heater, including the heating elements and their support
structure are extremely hot during operation. Allow sufficient
time for them to cool before working within the cabinet. Use
extreme caution and wear protective gloves and arm protection
when working on or near the heater.
31.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
SAVE THIS MANUAL
UNIT RECORDS
Record information as shown below. In the unlikely event that factory assistance is ever
required, this information will be needed.
Serial Number:
Heater Model No:
Locate the RenewAire unit label, found on the door of the electric duct heater.
NOTE: This information is for purposes of identifying the specific furnace. Unit-specific option
data can then be obtained, as needed, from the Model Number. See Electric Heater Code in this
manual for further details.
TYPICAL ELECTRIC DUCT HEATER LABEL
ELECTRIC DUCT HEATER
MODEL NUMBER
SERIAL NUMBER
SO#
NOTE: This page
is to be completed
by the installing
contractor. The completed
document is to be turned
over to the owner after
start-up.
OWNER INFORMATION
SO Number:
1.800.627.44994
OPTIONS & ACCESSORIES
Specifications may be subject to change without notice.
0
25
50
75
100
125
150
175
200
02500 5000 7500 10000 12500
HEATER CAPACITY -kW
AIRFLOW -CFM
EK Series Heater Capacity
SAFE OPERATING
RANGE
EK SERIES HEATER CAPACITY
ELECTRIC DUCT HEATER SPECIFICATIONS
Heater Type:
Electric Duct Heater
Typical KW Range:
1–175 kW
Standard Features:
A disconnecting magnetic control contactor per
stage or each 48 Amp circuit within a stage
Open-coil element
Staged on/off
Control terminal board
Grounding lugs
Automatic limit switch for primary over-
temperature protection
Manual reset limit switch for secondary over-
temperature protection
Non-adjustable airflow switch
Standard control transformer - 24 VAC
Disconnect switch
Duct thermostat with sensor for on/off control
60-20-20 (Ni/Cr/Fe) C Grade element wire with
nickel-plated terminals
Slip-in mount
No left/right hand
Vertical up/down flow
Voltages & Phase:
Single phase - 120, 208, 240, 277
Three phase - 208, 240, 480, 600
Control Voltage:
24 VAC
Dimensions:
Minimum - 8" x 8" (W x H)
Maximum - 99" x 99" (W x H)
Options:
Flange mount
80-20 (Ni/Cr) A Grade element wire with
stainless steel terminals
Recessed control box 1"
Gasketed cover - dust tight
Power fusing, standard for heaters drawing more
than 48 Amps
2-stage
Electronic step controller (4-stage)
SCR (up to 96 Amps)
SCR Vernier (over 96 Amps)
Pilot light
Accessory:
Room thermostat
Room/duct thermostat-sensor kit for SCR control
Note: Electric duct heater designed for indoor ductwork installation only.
SERIESEK Electric Duct Heater (1-175 kW)
Accessory
Download specification at:
renewaire.com/specifications
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
02004006008001000120014001600180020002200
PRESSURE DROP THROUGH HEATER
Static Pressure Drop - Inches of Water
Air Velocity - FPM (1, 2, 3 and 4 - the number of rows of heater coils)
When the number of rows of heater coils is unknown, assume 4.
1
2
3
4
PRESSURE DROP THROUGH HEATER
FLIPPABLE
CAPABILITIES
Unique to the EK series, this unit has the ability
to flip 180°. Additionally, EK heaters features
both vertical up and vertical down airflow.
SLIP-IN
CONSTRUCTION
SHOWN
AIR DUCT
FIGURE: 4
BASE
HEATER
BASE
HEATER
ROTATED
180o
BASE
HEATER
BASE HEATER
FLIPPED 180°
* ONE HEATER- 4
POSITIONS
3
HORIZONTAL DUCT & AIRFLOW
with HORIZONTAL INSTALLATION
AIRFLOW
p
g
VERTICAL DUCT & AIRFLOW
AIRFLOW
AIRFLOW
* SAME HEATER- FOR
VERTICAL DUCTS
AIRFLOW
51.800.627.4499
NOTES:
1. W and H determined by duct size
A. For slip-in
W = Duct width minus 1/4 inch
H = Duct height minus 1/16 inch
B. flange mount
W and H=Duct size
2. U = (W+H Up to 60"=4 7/8), (61" and over U=6")
(W greater than 36" U=6")
3. BD = 4 1/4, 6, 8 1/2, or 10 1/4 depth of control box depends on the
components required and size of power entry holes
4. Z = (H+2" standard for slip in) (H+4" for flange mount)
5. T = 1" standard
6. M = 1" standard
7. Q = (12" minimum) Size depends on required components.
Consult factory for dimensions
8. F = 9/16" for slip-in type
1" for flange mount
9. R = 1 1/2" when using 4 7/8" U dimension
15/16" when using 6" U dimension
10. N = Q minus R and U
NOTE: R and N dimensional values exchange position for right hand offset.
500 Gould Drive, Cookeville, TN 38506
Phone: (931) 432-4141 • 1 (877) 262-4533 • Fax: (931) 432-4140
www.tutco.com
TECHNICAL DATA
®
ITEM QTY SERIES KW PH VOLTS STG CTL VLT S/F KW/STG W H Q Z U BD F R N T M
1. W and H determined by duct size
A. For slip-in
W = Duct width minus 1/4 inch
H = Duct height minus 1/16 inch
B. flange mount
W and H=Duct size
2. U = (W+H Up to 60"=4 7/8), (61" and over U=6")
(W greater than 36" U=6")
3. BD = 4 1/4, 6, 8 1/2, or 10 1/4 depth of control box
depends on the components required and size
of power entry holes
4. Z = (H+2" standard for slip in) (H+4" for flange mount)
5. T = 1" standard
6. M = 1" standard
7. Q = (12" minimum) Size depends on required components.
Consult factory for dimensions
8. F = 9/16" for slip-in type
1" for flange mount
9. R = 1 1/2" when using 4 7/8" U dimension
15/16" when using 6" U dimension
10. N = Q minus R and U
Note: R and N dimensional values exchange position for right hand offset.
FORMULAS FOR FIGURING KW
AND TEMPERATURE RISE
The following fomula may be used to determine
the approximate total KW required when the CFM
(air volume) and desired temperature rise are known:
KW =
DETERMINING THE TEMPERATURE RISE
OF A DUCT HEATER
The following formula may be used to determine
the approximate temperature rise of a duct heater
when the KW and CFM are known:
T.R. =
CFM X T.R.
3150
KW X 3150
CFM
R
R
F
F
W
W
M*
M*
T*
T*
U
U
Q*
Q*
BD*
BD*
Z*
Z*
N
N
OFFSET LEFT
STANDARD
OFFSET RIGHT
OPTIONAL
H
H
R
R
F
F
W
W
M*
M*
T*
T*
U
U
Q*
Q*
BD*
BD*
Z*
Z*
N
N
OFFSET LEFT
STANDARD
OFFSET RIGHT
OPTIONAL
H
H
TYPE S SLIP-IN
TYPE F FLANGE MOUNT
= Dimensions do not include allowance for
control box cover. Control box cover will
be larger than the control box.
*
PRODUCT DIMENSIONS
ELECTRIC DUCT HEATER
ABBREVIATIONS
W Width
H Height
1.800.627.44996
EK-Series Electric Duct Heater
ACCESSORY
TABLE OF CONTENTS
1.0 OVERVIEW 11
1.1 DESCRIPTION .......................................................11
1.2 ELECTRICAL SUPPLY.............................................11
1.3 HEATER CAPACITY IN KILOWATTS .........................12
1.4 HEATER ELEMENTS ..............................................12
1.5 SAFETY FEATURES ...............................................12
1.5.1 Airflow Switch ..................................................................12
1.5.2 Automatic Reset Limit Switch............................................12
1.5.3 Manual Reset Limit Switches ............................................12
1.6 HEATER CONTROL ................................................13
1.7 HEAT RISE............................................................13
1.8 USER INTERFACE .................................................13
2.0 SYSTEM REQUIREMENTS 14
2.1 GENERAL OPERATING REQUIREMENTS..................14
2.2 SIZING AN ELECTRIC DUCT HEATER ......................14
2.3 AMPERAGE DRAW ................................................14
2.4 KW AND TEMPERATURE RISE................................14
2.5 DUCT HEATER TEMPERATURE RISE.......................14
2.6 DETERMINING MAXIMUM HEATER KW...................14
2.7 MINIMUM AIR VELOCITIES ....................................15
3.0 HEATER PLACEMENT 16
3.1 GENERAL .............................................................16
4.0 ELECTRICAL DATA 19
4.1 TYPICAL CONTACTOR POWER CIRCUITRY ..............19
4.2 HEATING ELEMENT WIRING CONFIGURATIONS AND
PROPERTIES ..............................................................19
4.3 HEATER WIRING SCHEMATICS...............................20
4.4 LOW VOLTAGE CONTROL SYSTEM..............................22
4.4.1 Specifications...................................................................22
4.4.2 Limits of Power Output .....................................................22
4.5 LOW VOLTAGE CONTROLS CONNECTION...................23
4.5.1 Interface Module Control Signal Wiring Connection Diagram
.................................................................................................23
4.5.2 Electronic Step Controller or SCR Control ..........................24
4.5.3 Staged Control .................................................................25
5.0 INSTALLATION 26
5.1 PLACEMENT OF THE ELECTRIC DUCT HEATER .......26
5.2 HEATER INSPECTION ............................................26
5.3 DUCT INSTALLATION.............................................27
6.0 OPERATING INSTRUCTIONS 28
6.1 ELECTRICAL REQUIREMENTS................................28
6.2 GENERAL OPERATING REQUIREMENTS..................28
7.0 MAINTENANCE 29
7.1 SERVICE PARTS....................................................29
8.0 FACTORY ASSISTANCE 30
71.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
TABLE OF ILLUSTRATIONS
TABLE OF WIRING SCHEMATICS
Figure 4.3.0 Single Phase On-Off Heater Wiring .....................................................................................20
Figure 4.3.1 Single Phase SCR Heater Wiring .........................................................................................20
Figure 4.3.2 Three Phase On-Off Heater Wiring......................................................................................21
Figure 4.3.3 Three Phase SCR Heater Wiring..........................................................................................21
Figure 4.5.0 Stand Alone Thermostat for Modulating Control ..................................................................23
Figure 4.5.1 DDC BAS for Modulating Control (2-10Vdc)..........................................................................23
Figure 4.5.2 DDC BAS for Modulating Control (4-20mA) .........................................................................23
Figure 4.5.3 Viconics Room Thermostat without Remote Sensor for Modulating Control ..........................24
Figure 4.5.4 Viconics Room Thermostat with Remote Sensor for Modulating Control for Return Air..........24
Figure 4.5.5 Viconics Room Thermostat with Remote Sensor for Modulating Control for Supply Air .........24
Figure 4.5.6 Single Stage Thermostat with Remote Sensor for On/Off Control.........................................25
Figure 4.5.7 2-Stage Thermostat with Remote Sensor for On/Off Control................................................25
Figure 1.1.0 Electric Heater (typical)....................................................................................................... 11
Figure 1.1.1 Control Panel Cover............................................................................................................. 11
Figure 1.1.2 Basic Control Panel............................................................................................................. 11
Figure 1.5.0 Heater Controls Identification ............................................................................................. 12
Figure 1.7.0 Heat Rise Calculation.......................................................................................................... 13
Figure 2.7.0 FPM vs. KW / Ft.2 Chart ...................................................................................................... 15
Figure 3.1.0 Placement: Minimum Airflows............................................................................................. 16
Figure 3.1.1 Placement: Elbow Minimum Requirement ............................................................................ 16
Figure 3.1.2 Placement: Location Requirements ..................................................................................... 16
Figure 3.1.3 Placement: Transition Requirements ................................................................................... 17
Figure 3.1.4 Placement: Downstream Requirements ............................................................................... 17
Figure 3.1.5 Placement: Humidifier Requirements................................................................................... 17
Figure 3.1.6 Placement: Air Filter Requirements ..................................................................................... 17
Figure 3.1.7 Placement: Obstruction Requirements................................................................................. 18
Figure 3.1.8 Placement: Control Box Requirements................................................................................. 18
Figure 3.1.9 Placement: Double Blower Requirements ............................................................................ 18
Figure 4.1.0 Typical Contactor Power Circuitry........................................................................................ 19
Figure 4.2.0 Heating Element Wiring Properties...................................................................................... 19
Figure 5.3.0 Slip-in Heater Installation ...................................................................................................27
Figure 5.3.1 Flange Heater Installation ...................................................................................................27
Figure 5.3.2 Common Installation Approaches........................................................................................27
Figure 7.1.0 Service Parts ......................................................................................................................29
TABLE OF CONTENTS
1.800.627.44998
EK-Series Electric Duct Heater
ACCESSORY
MODEL NUMBER
Heater Type
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
"EK "= Electric Heater (Standard)
DIGIT NUMBER
Digits 1 - 2:
Width in Inches (see Restriction 1)
Digits 4 - 5:
08-99
Mount
Digit 11:
"S" = Slip In (Standard)
"F = Flanged
Element Style
Digit 12:
"C" = Open Coil (Standard)
Element Material
Digit 13:
"C" = 60-20-20 Ni-Cr-Fe with Nickel Plate Terminal Pins (Standard)
"A" = 80-20 Ni-Cr with Stainless Steel Terminal Pins
Airflow Orientation
Digit 14:
"H" = Horizontal (Standard)
"V" = Vertical
Control Box Offset
Digit 15:
"L" = Left Hand (Standard)
"R" = Right Hand
*NOTES:
Digit 3 is not used in this model.
All heaters come with standard features: Disconnect Switch, Air Flow Switch (non adjustable), Control Transformer
Descriptions of feature and options are found in the installation and operation manual.
Restrictions:
1: Width inches entered as a whole number.
2: Height inches entered as a whole number.
3: Heater density should be less than 30kW/ft². DENSITY= HEATER CAPACITY (kW) < 30
(W" x H")/144
4: Heater capacity kW entered as a whole number.
5: Formulas for calculating kW and temperature rise: kW = CFM x ΔT ΔT = kW x 3150
3150 CFM
7: Voltage Codes "1" & "9" only available with Phase Code "1" (Single-Phase).
8: Voltage Codes "4" & "8" only available with Phase Code "3" (Three-Phase).
9: Power Fusing Code "F" required when amperage is >48A. (based on kW and voltage)
10: Control Type Code "D" only available with Stage Code "1" & "2".
11: Control Type Code "E" only available with Stage Code "4".
12: Control Type Code "S" & "V" only available with Stage Code "1", unless amperage is greater than or equal to 96A, then Stage Code "4" is automatically selected.
Voltage (see Restrictions 7 & 8)
Digit 18:
"1" = 120V
"2" = 208V
"3" = 240V
"4" = 480V
"8" = 600V
"9" = 277V
Phase
Digit 19:
"1" = Single-Phase
"3" = Three-Phase
Stage
Digit 21:
"1" = Single (Standard)
"2" = 2-Stage
"4" = 4-Stage
Control Voltage
Digit 22:
"S" = 24VAC
Time Delay
Digit 24:
"-" = None (Standard)
-
Height in Inches (see Restriction 2)
Digits 6 - 7:
08-99
Capacity in kW (see Restrictions 3, 4 & 5)
Digits 8 - 10:
001-175
Control Box Recessed
Digit 16:
"-" = None (Standard)
"R" = Recessed 1"
Power Fusing (see Restriction 9)
Digit 20:
"-" = None
"F" = Fusing
Control Type (see Restrictions 10, 11 & 12)
Digit 23:
"D" = Duct Thermostat with Sensor (Standard)
"E" = Electronic Step Control with Sensor
"S" = SCR (For BAS System)
"V" = SCR with Analog Sensor (0-10Vdc)
Pilot Light
Digit 25:
"N" = None (Standard)
"L" = Light
Control Box Dust Tight
Digit 17:
"-" = None (Standard)
"D" = Dust Tight
ELECTRIC POST HEAT
CONFIGURATION CODE CHART
Each RenewAire Electric Duct Heater is assigned a 25 digit Model Number. The Model Number
can be used to identify the various options as ordered by the customer.
ELECTRIC DUCT HEATER CONFIGURATION CODE
CONFIGURATION CODE
91.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
Heater Type:
EK—(Standard) heater 8"–99" height
and width.
Width:
W—Width of duct ID in inches. For slip-in
type the W dimension is undersized by ¼"
to allow heater to slip into ductwork.
Range 8"–99"
Height:
H—Height of duct ID in inches. For slip-
in type the H dimension is undersized
by 1/16" to allow heater to slip into
ductwork.
Range 8"–99"
Capacity:
KW—Kilowatt rating of heater.
Determined by airflow (CFM) and
temperature rise (rT).
Range 1–175 KW
Mount:
Slip-in (Standard)—heater is installed
through opening cut into side of duct and
the control box is attached to duct.
Flanged (Option)—heater is installed
between two sections of flanged duct and
bolted in place.
Element Style:
Open Coil (Standard)—open coil
resistance wire. Used in most
applications.
Element Material:
60-20-20 NI-CR-FE with nickel plate
terminal pins (Standard)—standard “C”
grade element wire. 60% nickel, 20%
chromium, 20% iron.
80-20 NI-CR with stainless steel terminal
pins (Option)—premium “A” grade
element wire.
80% nickel, 20% chromium.
Airflow Orientation:
Horizontal (Standard)—heater installed
where airflow in ductwork is horizontal
through the heater.
Vertical (Option)—heater installed where
airflow in ductwork is vertical through
the heater. Vertical up and down airflow
available in EK series
Control Box Offset:
Left Hand (Standard)—the control panel is
offset to the left side of the heating elements
as determined when looking into the control
box.
Right Hand (Option)—the control panel is
offset to the right side of the heating elements
as determined when looking into the control
box.
Control Box Recessed (Option):
Recessed 1"—Control box is designed
to extend 1" beyond internally insulated
duct. Heater element width construction is
automatically reduced by 1". Heater element
height construction is automatically reduced
by 2". Recess depth dimension is 1". Only
allowed for internally insulated ducts of 1"
insulation thickness.
Control Box Dust Tight (Option):
Dust Tight—Compression type gasket
installed on control box flanges to seal door
opening. Control box seams are filled to
prevent dust intrusion. Typically specified
when local code requires it.
Voltage and Phase:
Single Phase—120V, 208V, 240V, 277V
3-Phase—208V, 240V, 480V, 600V
Power Fusing:
Required by UL and NEC if amperage is over
48A. Otherwise is an option.
Stage:
Single Stage (Standard)—All heating
elements are energized simultaneously. SCR
control is always single stage.
2-Stage (Option)—Heating capacity is divided
into two sections. Half of the heating capacity
can be energized when less heating is
required. Both stages are energized when full
heating is required. Can be for on/off control.
4-Stage—Heating capacity is divided into
four sections. 4-stage for Electronic Step
Control only.
Control Voltage:
24 VAC (Standard)—secondary voltage
DEFINITIONS FOR CONFIGURATION CODE
CONFIGURATION CODE
1.800.627.449910
EK-Series Electric Duct Heater
ACCESSORY
Control Type:
Duct Thermostat with sensor—standard
thermostat with on/off control. Sensor
is duct mounted. Thermostat must be
programmed by installer for the number
of stages. (Standard)
Electronic Step Control—provides
sequencing control in steps of 4 for duct
heater. Converts analog input signal
into discrete steps or stages. As an
example, if you have a 4-stage heater
the step controller would be 4-stage. For
an analog signal greater than 4Vdc the
first stage would energize, for an analog
signal greater than 6Vdc the first and
second stages would energize, for an
analog signal greater than 8Vdc the first,
second, and third stages would energize,
and for an analog signal at 10Vdc all
stages would energize.
Silicon Controlled Rectifier (SCR)—100%
step-less modulating control. Accepts
0-10Vdc or 4-20mA as control signal.
Utilizes solid state relays (SSR) to switch
current to the heating elements, on a
time-proportioned basis.
SCR Vernier—When SCR control is
selected and the heater is greater than
96A then an SCR vernier control is
implemented. This combines an SCR with
4-stage electronic step control as a cost
effective method for providing modulating
control on heaters greater than 96A.
A SSR is an electronic switching device
similar to an electromechanical relay
(contactor) but has no moving parts
which allows very fast switching of high
current loads without arcing or wearing
out. A heater with an SCR controller must
be installed in such a way as to provide
good ventilation to the heat sink so that
the life of the SSR is prolonged. Over-
heating of an SSR causes it to fail so the
heater must be installed such that the
heat sink is positioned either vertically
on the side of the control cabinet or on
top of the control cabinet—never on the
bottom.
Pilot Light Option:
Light to indicate heater energized. Control
voltage same as transformer secondary
voltage (24 VAC).
Airflow Switch: (Standard)
Non-adjustable pressure switch that
prevents the heater from being energized
when no or very low air flow is present
through the heater. Minimum air flow
pressure is 0.05 in.w.c + .02.
Auto Reset: (Standard)
Automatic reset limit switch for primary
over-temperature protection. Required by
UL.
Manual Reset: (Standard)
Manual reset limit switch for secondary
over-temperature protection. Required by
UL.
Disconnect Switch: (Standard)
Non-fused interlocking switch mounted in
the door of the heater control box. Must
be turned off to open door on control
box. Interrupts power to the heater when
turned off.
Terminal Block: (Standard)
Low voltage control terminal block
included.
Ground Lug: (Standard)
Connection point for grounding field
connected line voltage.
All heaters are designed for zero
clearance.
Control box is constructed of galvanized
steel.
Control box has hinged access door with
interlocking disconnect switch.
All heaters are UL and cUL listed and
tested in accordance with Standard
UL1996.
CONFIGURATION CODE
111.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
1.0 OVERVIEW
The model EK electric duct heater is an open-coil type heater for indoor installation only.
Multiple voltages and heater sizes are offered. A number of different control options are offered.
1.1 DESCRIPTION
1.2 ELECTRICAL SUPPLY
The electric duct heater requres both line voltage and low voltage circuits with correct polarity
and clean neutral and ground. Line voltage readings between each leg should be within +/- 3
volts of the voltage rating on the heater rating label, found on the door of the control panel.
FIGURE 1.1.0 ELECTRIC HEATER (TYPICAL)
FIGURE 1.1.1 CONTROL PANEL COVER
FIGURE 1.1.2 BASIC CONTROL PANEL
OVERVIEW
1.800.627.449912
EK-Series Electric Duct Heater
ACCESSORY
1.4 HEATER ELEMENTS
1.5 SAFETY FEATURES
A choice of two different types of heater elements is offered: either 60–20–20 Ni–Cr –Fe with
nickel plated terminal pins (standard) or 80-20 Ni-Cr with stainless steel terminal pins.
Each heater is equipped with the following:
1.5.1 Airflow Switch
The airflow switch is a non-adjustable pressure switch that prevents the heater from being
energized when no or very low air flow is present.
1.5.2 Automatic Reset Limit Switch
The auto reset limit switch is mounted on the heater next to the elements. If the limit switch
detects temperatures greater than 130 degrees Fahrenheit [54.40C], it shuts down the heater
until the temperature drops and then the limit switch automatically resets itself.
1.5.3 Manual Reset Limit Switches
There are two manual reset limit switches on the heater, located next to the heater elements. If
the limit switch detects temperatures in excess of 200 degrees Fahrenheit [93.30C], the limit
switch trips and shuts off the heater. The limit switch must be manually reset.
1.3 HEATER CAPACITY IN KILOWATTS
Electric heater capacity is based on kilowatts (kW). Electric heaters are nearly 100% efficient,
so output capacity equals input capacity. Heaters are available in capacities from 1 - 175 kW.
MANUAL RESET
LIMIT SWITCHES
AUTO RESET
LIMIT SWITCH
AIRFLOW
SWITCH
AIRFLOW SWITCH
PROBE
LIMIT SWITCHES
DISCONNECT
SWITCH
SOLID STATE
RELAY (SSR)
CONTACTORS
SIGNAL INTERFACE
MODULE (SIM)
FIGURE 1.5.0 HEATER CONTROLS IDENTIFICATION
OVERVIEW
131.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
1.6 HEATER CONTROL
Electric duct heaters are configured with either staged or modulating control. The options
available are:
uSingle Stage
u2-stage
u4-stage
Single stage control is when all heating elements are energized simultaneously. Single stage
control can be either simple ON/OFF or modulating.
2-stage control has the heating capacity divided into two sections. Half of the heating capacity
is energized when less heating is required. Both stages are energized when full heating is
required. 2-stage control is always ON/OFF.
4-stage control is when the heating capacity is divided into four sections. This provides
sequencing control in four steps for the heater. The heater controller converts an analog input
signal into discrete steps or stages to energize each stage of the heating elements. 4-stage
control is always Electronic Step Control.
1.7 HEAT RISE
The User Interface (U/I) is the device used to control operation of the electric duct heater.
Single and 2-stage heaters are ordered with a 2-stage duct thermostat and sensor. Modulating
heaters can be ordered with an analog thermostat and sensor. The user interface may be a
simple ON/OFF thermostat, modulating thermostat, or even a Building Management System
(BMS).
uMaximum allowable discharge temperature is 120˚ F [48.9˚ C] for any installation.
uMaximum allowable temperature rise is 90˚ F [50˚ C].
uMaximum design duct static pressure is 3.0 InWC .
Note that the example below is based upon a specific Entering Air temperature. As Entering Air
temperatures vary, the resulting temperature rise will also vary.
1.8 USER INTERFACE
FIGURE 1.7.0 HEAT RISE CALCULATION
3000 CFM
45 ˚F Entering
Air Temp
30 kW
Input
31.5 ˚F Rise
76 ˚F
Discharge
Air Temp
OVERVIEW
1.800.627.449914
EK-Series Electric Duct Heater
ACCESSORY
2.0 SYSTEM REQUIREMENTS
2.1 GENERAL OPERATING REQUIREMENTS
Minimum Air Velocity: 70 CFM per KW (75-80 Recommended)
Maximum Inlet Air Temp: 100 Deg. F [37.80 C]
Maximum Heater KW: 30 kW per square foot of heater cross section.
2.4 KW AND TEMPERATURE RISE
2.3 AMPERAGE DRAW
Any electric duct heater with line current over 48 amps automatically receives fusing per UL
and NEC requirements. Electric duct heaters over 48 amps are subdivided into loads less than
48 amps. Formula for calculating line current are:
Single Phase: Amps = Watts/Line Voltage
Three Phase: Amps = Watts/(Line Voltage x 1.73)
To convert kW to Watts multiply kW by 1000
2.5 DUCT HEATER TEMPERATURE RISE
2.6 DETERMINING MAXIMUM HEATER KW
2.2 SIZING AN ELECTRIC DUCT HEATER
An electric duct heater can be sized from the following information:
uDuct Width (W") and Duct Height (H")
uHeater voltage and phase
uHeater Capacity rating (kW)
uOr Design Air Flow (CFM) and
uDesired Temperature Rise (∆ °F)
The following formula may be used to determine the approximate total kW required when the
CFM (air volume) and desired temperature rise are known:
kW = CFM x rT
3150
The following formula may be used to determine the approximate temperature rise of a duct
heater when the kW and CFM are known:
rT = KW x 3150
CFM
MAXIMUM WATTS PER SQ. IN. OF DUCT AREA
Duct width (inches) x duct height (inches) = duct watts total sq. in.
Max W = Xw x duct area in2
in2
For EK, X= 208.33 w
in2
MAXIMUM KW FOR SQ. FT. OF DUCT AREA
Duct width (feet) x duct height (feet) = duct area total ft2
Max W = X kW x duct area ft2
ft2
For EK, X= 30 kW
ft2
SYSTEM REQUIREMENTS
NOTE: The air tem-
perature entering
the heater should
not exceed that
marked on the heater
nameplate label.
151.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
2.7 MINIMUM AIR VELOCITIES
The minimum uniform airflow in a duct heater is directly related to the inlet air temperature.
Consideration must be given to both airflow across the heater and inlet air temperature, (shown
below).
To calculate the kilowatts per sq. ft. of duct area, divide the total kilowatts required by the duct
area.
EXAMPLE: Duct Size = 2ft. x 3ft.
Total kilowatts = 20
KW/Sq. Ft. = 20 = 3.333
6
If the air handler equipment is expressed in FPM then a direct cross reference can be made by
comparing the temperature of the air (as it enters the Duct Heater) to the KW rating on the chart
of rated velocity.
a. Draw a line horizontally from the KW/Sq. Ft. required to the inlet air temperature being used.
b. From this point of intersection on the Inlet Air Curve, draw a line down vertically to establish
the air velocity.
c. The velocity should never be lower than the velocity as determined from the chart. In cases
where this is not true, the velocity must be increased or the KW required must be reduced.
In cases where the air handling equipment is expressed in CFM then convert to FPM by dividing
the CFM by the duct area.
EXAMPLE: FPM = CFM
Duct Area
SYSTEM REQUIREMENTS
NOTE: Minimum
airflow must be
maintained at any
point over the face of
the heater.
NOTE: Observe at
least one complete
heating cycle to
ensure that cycling
of the safety limit controls
does not occur before
leaving the installation.
FIGURE 2.7.0 FPM VS KW/ FT2CHART
1.800.627.449916
EK-Series Electric Duct Heater
ACCESSORY
3.1 GENERAL
3.0 HEATER PLACEMENT
A duct heater must be installed according to the installation instructions, wiring diagram and
labeling supplied with the heater.
Listed below are some important items when installing an electric duct heater:
1. Never operate a duct
heater without airflow. The
heater must always be
interlocked with the fan.
This may be accomplished
by either an airflow switch
or fan interlock relay.
2. Never operate heater
without achieving at least
the minimum airflow
required. Always refer to
the installation instructions
and the nameplate label to
determine your minimum
air velocities based on
your inlet air temperature.
If the minimum airflow
requirements are not
present the heater will
not function properly and
safely. (see Figure 3.1.0)
3. Never operate the heater
with uneven airflow.
The minimum airflow
requirements must be
present at all points over
the heater face. (see
Figure 3.1.0)
4. The air must be filtered.
The incoming air must
be free from all debris,
combustible particles, and
hazardous vapors.
5. Always locate the heater at
least 24" from an elbow or
turn. (See Figure 3.1.1)
6. Always locate the heater
at least 48" from an ERV,
heat pump or central air
conditioner. (See Figure
3.1.2)
500 fpm
470 fpm
780 fpm
ELECTRIC DUCT HEATER
TROUBLESHOOTING GUIDE
24" MIN.
48" MIN.
HEAT PUMP OR
AIR CONDITIONER
HEATER
HEATER
DUCT
DUCT
HEATER
48" MIN. 48" MIN.
HEATER
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
CORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE PRESENT
INCORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE NOT PRESENT
INCORRECT
MIN. AIRFLOW IS NOT PRESENT
INCORRECT
CORRECT
FIG. 1
FIG. 2
FIG. 3
FIG. 4
A DUCT HEATER MUST BE INSTALLED ACCORDING
TO THE INSTALLATION INSTRUCTIONS, WIRING
DIAGRAM AND LABELING SUPPLIED WITH THE
HEATER.
Listed below are some important items when installing
a electric duct heater:
1. NEVER OPERATE A DUCT HEATER WITHOUT
AIRFLOW.
The heater must always be interlocked with the
fan. This may be accomplished by either an airflow
switch or fan interlock relay.
2. NEVER OPERATE HEATER WITHOUT ACHIEVING
AT LEAST THE MINIMUM AIRFLOW REQUIRED.
Always refer to the installation instructions and
the nameplate label to determine your minimum
air velocities based on your inlet air temperature.
If the minimum airflow requirements are not
present the heater will not function properly and
safely. (see fig. 1)
3. NEVER OPERATE THE HEATER WITH UNEVEN
AIRFLOW.
The minimum airflow requirements must be
present at all points over the heater face.
(see fig. 1)
4. THE AIR MUST BE FILTERED.
The incoming air must be free from all debris,
combustible particles, and hazardous vapors.
5. ALWAYS LOCATE THE HEATER AT LEAST 24"
FROM AN ELBOW OR TURN.
(see fig. 2)
6. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM AN HEAT PUMP OR CENTRAL AIR
CONDITIONER.
(see fig. 3)
7. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM ANY CANVAS DUCT CONNECTOR OR
TRANSITION SECTION FOR CHANGE IN DUCT
SIZE.
(see fig. 4)
8. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR HANDLER.
(see fig. 5)
9. ALWAYS LOCATE THE HEATER AT LEAST 48"
UPSTREAM FROM AN HUMIDIFIER.
(see fig. 6)
470 fpm
470 fpm
780 fpm
780 fpm
DUCT
DUCT
PAGE 1 OF 2
NOTE: ALL FIGURES ARE SHOWING A TOP
VIEW OF A HORZONTIAL DUCT.
780 fpm
780 fpm
500 GOULD DRIVE COOKEVILLE, TN 38506
FAX (931)432-4140 PHONE (931)432-4141
INC.
500 fpm
470 fpm
780 fpm
ELECTRIC DUCT HEATER
TROUBLESHOOTING GUIDE
24" MIN.
48" MIN.
HEAT PUMP OR
AIR CONDITIONER
HEATER
HEATER
DUCT
DUCT
HEATER
48" MIN. 48" MIN.
HEATER
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
CORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE PRESENT
INCORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE NOT PRESENT
INCORRECT
MIN. AIRFLOW IS NOT PRESENT
INCORRECT
CORRECT
FIG. 1
FIG. 2
FIG. 3
FIG. 4
A DUCT HEATER MUST BE INSTALLED ACCORDING
TO THE INSTALLATION INSTRUCTIONS, WIRING
DIAGRAM AND LABELING SUPPLIED WITH THE
HEATER.
Listed below are some important items when installing
a electric duct heater:
1. NEVER OPERATE A DUCT HEATER WITHOUT
AIRFLOW.
The heater must always be interlocked with the
fan. This may be accomplished by either an airflow
switch or fan interlock relay.
2. NEVER OPERATE HEATER WITHOUT ACHIEVING
AT LEAST THE MINIMUM AIRFLOW REQUIRED.
Always refer to the installation instructions and
the nameplate label to determine your minimum
air velocities based on your inlet air temperature.
If the minimum airflow requirements are not
present the heater will not function properly and
safely. (see fig. 1)
3. NEVER OPERATE THE HEATER WITH UNEVEN
AIRFLOW.
The minimum airflow requirements must be
present at all points over the heater face.
(see fig. 1)
4. THE AIR MUST BE FILTERED.
The incoming air must be free from all debris,
combustible particles, and hazardous vapors.
5. ALWAYS LOCATE THE HEATER AT LEAST 24"
FROM AN ELBOW OR TURN.
(see fig. 2)
6. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM AN HEAT PUMP OR CENTRAL AIR
CONDITIONER.
(see fig. 3)
7. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM ANY CANVAS DUCT CONNECTOR OR
TRANSITION SECTION FOR CHANGE IN DUCT
SIZE.
(see fig. 4)
8. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR HANDLER.
(see fig. 5)
9. ALWAYS LOCATE THE HEATER AT LEAST 48"
UPSTREAM FROM AN HUMIDIFIER.
(see fig. 6)
470 fpm
470 fpm
780 fpm
780 fpm
DUCT
DUCT
PAGE 1 OF 2
NOTE: ALL FIGURES ARE SHOWING A TOP
VIEW OF A HORZONTIAL DUCT.
780 fpm
780 fpm
500 GOULD DRIVE COOKEVILLE, TN 38506
FAX (931)432-4140 PHONE (931)432-4141
INC.
500 fpm
470 fpm
780 fpm
ELECTRIC DUCT HEATER
TROUBLESHOOTING GUIDE
24" MIN.
48" MIN.
HEAT PUMP OR
AIR CONDITIONER
HEATER
HEATER
DUCT
DUCT
HEATER
48" MIN. 48" MIN.
HEATER
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
CORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE PRESENT
INCORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE NOT PRESENT
INCORRECT
MIN. AIRFLOW IS NOT PRESENT
INCORRECT
CORRECT
FIG. 1
FIG. 2
FIG. 3
FIG. 4
A DUCT HEATER MUST BE INSTALLED ACCORDING
TO THE INSTALLATION INSTRUCTIONS, WIRING
DIAGRAM AND LABELING SUPPLIED WITH THE
HEATER.
Listed below are some important items when installing
a electric duct heater:
1. NEVER OPERATE A DUCT HEATER WITHOUT
AIRFLOW.
The heater must always be interlocked with the
fan. This may be accomplished by either an airflow
switch or fan interlock relay.
2. NEVER OPERATE HEATER WITHOUT ACHIEVING
AT LEAST THE MINIMUM AIRFLOW REQUIRED.
Always refer to the installation instructions and
the nameplate label to determine your minimum
air velocities based on your inlet air temperature.
If the minimum airflow requirements are not
present the heater will not function properly and
safely. (see fig. 1)
3. NEVER OPERATE THE HEATER WITH UNEVEN
AIRFLOW.
The minimum airflow requirements must be
present at all points over the heater face.
(see fig. 1)
4. THE AIR MUST BE FILTERED.
The incoming air must be free from all debris,
combustible particles, and hazardous vapors.
5. ALWAYS LOCATE THE HEATER AT LEAST 24"
FROM AN ELBOW OR TURN.
(see fig. 2)
6. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM AN HEAT PUMP OR CENTRAL AIR
CONDITIONER.
(see fig. 3)
7. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM ANY CANVAS DUCT CONNECTOR OR
TRANSITION SECTION FOR CHANGE IN DUCT
SIZE.
(see fig. 4)
8. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR HANDLER.
(see fig. 5)
9. ALWAYS LOCATE THE HEATER AT LEAST 48"
UPSTREAM FROM AN HUMIDIFIER.
(see fig. 6)
470 fpm
470 fpm
780 fpm
780 fpm
DUCT
DUCT
PAGE 1 OF 2
NOTE: ALL FIGURES ARE SHOWING A TOP
VIEW OF A HORZONTIAL DUCT.
780 fpm
780 fpm
500 GOULD DRIVE COOKEVILLE, TN 38506
FAX (931)432-4140 PHONE (931)432-4141
INC.
PLACEMENT
NOTE: An airflow
switch only proves
that airflow exists (a
differential in static
pressure), not that the
minimum air velocities and
proper air distribution for
the duct heater exist.
NOTE: All figures are
showing a top view
of a horizontal duct.
FIGURE 3.1.0 PLACEMENT:MINIMUM AIRFLOWS
FIGURE 3.1.1 PLACEMENT: ELBOW MINIMUM REQUIREMENT
FIGURE 3.1.2 PLACEMENT: LOCATION REQUIREMENTS
171.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
500 fpm
470 fpm
780 fpm
ELECTRIC DUCT HEATER
TROUBLESHOOTING GUIDE
24" MIN.
48" MIN.
HEAT PUMP OR
AIR CONDITIONER
HEATER
HEATER
DUCT
DUCT
HEATER
48" MIN. 48" MIN.
HEATER
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
EXAMPLE: IF 780 fpm IS REQUIRED
CORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE PRESENT
INCORRECT
MIN. AIRFLOW AND EVEN AIR
DISTRIBUTION ARE NOT PRESENT
INCORRECT
MIN. AIRFLOW IS NOT PRESENT
INCORRECT
CORRECT
FIG. 1
FIG. 2
FIG. 3
FIG. 4
A DUCT HEATER MUST BE INSTALLED ACCORDING
TO THE INSTALLATION INSTRUCTIONS, WIRING
DIAGRAM AND LABELING SUPPLIED WITH THE
HEATER.
Listed below are some important items when installing
a electric duct heater:
1. NEVER OPERATE A DUCT HEATER WITHOUT
AIRFLOW.
The heater must always be interlocked with the
fan. This may be accomplished by either an airflow
switch or fan interlock relay.
2. NEVER OPERATE HEATER WITHOUT ACHIEVING
AT LEAST THE MINIMUM AIRFLOW REQUIRED.
Always refer to the installation instructions and
the nameplate label to determine your minimum
air velocities based on your inlet air temperature.
If the minimum airflow requirements are not
present the heater will not function properly and
safely. (see fig. 1)
3. NEVER OPERATE THE HEATER WITH UNEVEN
AIRFLOW.
The minimum airflow requirements must be
present at all points over the heater face.
(see fig. 1)
4. THE AIR MUST BE FILTERED.
The incoming air must be free from all debris,
combustible particles, and hazardous vapors.
5. ALWAYS LOCATE THE HEATER AT LEAST 24"
FROM AN ELBOW OR TURN.
(see fig. 2)
6. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM AN HEAT PUMP OR CENTRAL AIR
CONDITIONER.
(see fig. 3)
7. ALWAYS LOCATE THE HEATER AT LEAST 48"
FROM ANY CANVAS DUCT CONNECTOR OR
TRANSITION SECTION FOR CHANGE IN DUCT
SIZE.
(see fig. 4)
8. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR HANDLER.
(see fig. 5)
9. ALWAYS LOCATE THE HEATER AT LEAST 48"
UPSTREAM FROM AN HUMIDIFIER.
(see fig. 6)
470 fpm
470 fpm
780 fpm
780 fpm
DUCT
DUCT
PAGE 1 OF 2
NOTE: ALL FIGURES ARE SHOWING A TOP
VIEW OF A HORZONTIAL DUCT.
780 fpm
780 fpm
500 GOULD DRIVE COOKEVILLE, TN 38506
FAX (931)432-4140 PHONE (931)432-4141
INC.
DUCT W/ INTERNAL INSULATION
DUCT W/ EXTERNAL INSULATION
10. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR FILTER.
(see fig. 7)
11. NEVER INSTALL A STANDARD HEATER INTO A
DUCT WITH AN INTERNAL OBSTRUCTION.
Due to the fact that an obstruction can block
airflow at the temperature limit controls and
element terminations. If this situation exist, it
can be corrected by using a heater with a
recessed control box and reduced wrapper size.
This situation is common with internally insulated
ducts. (see fig. 8)
12. NEVER INSULATE THE EXTERIOR OF THE
CONTROL BOX.
The control box must be completely accessible
and located where ventilation can be provided at
all times. (see fig. 9)
13. NEVER INSTALL A HEATER NEAR A DOUBLE
BLOWER OUTLET.
A heater must be installed far enough away from
a double blower outlet that even and proper
airflow is present or separate duct heaters
placed in the duct runouts of each blower. (all
installation must conform with the heater
installation instructions.) (see fig. 10)
14. NEVER INSTALL A HEATER LESS THAN 48"
FROM ANY FAN.
Mounting a heater any closer than 48" to a fan
will result in uneven airflow.
15. ORDER THE HEATER WITH THE FACTORY
INSTALLED LINEAR TEMPERATURE LIMIT
CONTROL IF THE HEATER WIDTH > 72".
16. NEVER USE ALUMINUM CONDUCTORS.
Use copper conductors only for all incoming
wiring.
17. NEVER INSTALL A STANDARD HEATER
OUTDOORS WITHOUT MAKING SPECIAL
PROVISIONS TO PROTECT THE HEATER
AND CONTROL BOX FROM THE ELEMENTS.
18. NEVER BUNDLE, TIE OR WRAP POWER WIRING.
The wire could overheat or the insulation could
breakdown.
19. NEVER USE A DIFFERENT VOLTAGE AND/OR
PHASE THAN WHAT IS LISTED ON THE HEATER
NAMEPLATE LABEL.
The duct heater is to be used only at the voltage
and phase that is listed on the nameplate label.
Note: An airflow switch only proves that airflow exist
(a differential in static pressure), not that the
minimum air velocities and proper air
distribution for the duct heater exist.
AIR HANDLER
HEATER
FIG. 5
FIG. 6
HEATER
HUMIDIFIER
AIR FILTER
HEATER
FIG. 7
48" MIN.
48" MIN.
CORRECT INCORRECT
CORRECT INCORRECT
FIG. 8
FIG. 9
FIG. 10
PAGE 2 OF 2
DUCT
DUCT
DUCT
VIEW OF A HORZONTIAL DUCT.
NOTE: ALL FIGURES ARE SHOWING A TOP
INCORRECT
48" MIN.
DUCT W/ INTERNAL INSULATION
DUCT W/ EXTERNAL INSULATION
10. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR FILTER.
(see fig. 7)
11. NEVER INSTALL A STANDARD HEATER INTO A
DUCT WITH AN INTERNAL OBSTRUCTION.
Due to the fact that an obstruction can block
airflow at the temperature limit controls and
element terminations. If this situation exist, it
can be corrected by using a heater with a
recessed control box and reduced wrapper size.
This situation is common with internally insulated
ducts. (see fig. 8)
12. NEVER INSULATE THE EXTERIOR OF THE
CONTROL BOX.
The control box must be completely accessible
and located where ventilation can be provided at
all times. (see fig. 9)
13. NEVER INSTALL A HEATER NEAR A DOUBLE
BLOWER OUTLET.
A heater must be installed far enough away from
a double blower outlet that even and proper
airflow is present or separate duct heaters
placed in the duct runouts of each blower. (all
installation must conform with the heater
installation instructions.) (see fig. 10)
14. NEVER INSTALL A HEATER LESS THAN 48"
FROM ANY FAN.
Mounting a heater any closer than 48" to a fan
will result in uneven airflow.
15. ORDER THE HEATER WITH THE FACTORY
INSTALLED LINEAR TEMPERATURE LIMIT
CONTROL IF THE HEATER WIDTH > 72".
16. NEVER USE ALUMINUM CONDUCTORS.
Use copper conductors only for all incoming
wiring.
17. NEVER INSTALL A STANDARD HEATER
OUTDOORS WITHOUT MAKING SPECIAL
PROVISIONS TO PROTECT THE HEATER
AND CONTROL BOX FROM THE ELEMENTS.
18. NEVER BUNDLE, TIE OR WRAP POWER WIRING.
The wire could overheat or the insulation could
breakdown.
19. NEVER USE A DIFFERENT VOLTAGE AND/OR
PHASE THAN WHAT IS LISTED ON THE HEATER
NAMEPLATE LABEL.
The duct heater is to be used only at the voltage
and phase that is listed on the nameplate label.
Note: An airflow switch only proves that airflow exist
(a differential in static pressure), not that the
minimum air velocities and proper air
distribution for the duct heater exist.
AIR HANDLER
HEATER
FIG. 5
FIG. 6
HEATER
HUMIDIFIER
AIR FILTER
HEATER
FIG. 7
48" MIN.
48" MIN.
CORRECT INCORRECT
CORRECT INCORRECT
FIG. 8
FIG. 9
FIG. 10
PAGE 2 OF 2
DUCT
DUCT
DUCT
VIEW OF A HORZONTIAL DUCT.
NOTE: ALL FIGURES ARE SHOWING A TOP
INCORRECT
48" MIN.
DUCT W/ INTERNAL INSULATION
DUCT W/ EXTERNAL INSULATION
10. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR FILTER.
(see fig. 7)
11. NEVER INSTALL A STANDARD HEATER INTO A
DUCT WITH AN INTERNAL OBSTRUCTION.
Due to the fact that an obstruction can block
airflow at the temperature limit controls and
element terminations. If this situation exist, it
can be corrected by using a heater with a
recessed control box and reduced wrapper size.
This situation is common with internally insulated
ducts. (see fig. 8)
12. NEVER INSULATE THE EXTERIOR OF THE
CONTROL BOX.
The control box must be completely accessible
and located where ventilation can be provided at
all times. (see fig. 9)
13. NEVER INSTALL A HEATER NEAR A DOUBLE
BLOWER OUTLET.
A heater must be installed far enough away from
a double blower outlet that even and proper
airflow is present or separate duct heaters
placed in the duct runouts of each blower. (all
installation must conform with the heater
installation instructions.) (see fig. 10)
14. NEVER INSTALL A HEATER LESS THAN 48"
FROM ANY FAN.
Mounting a heater any closer than 48" to a fan
will result in uneven airflow.
15. ORDER THE HEATER WITH THE FACTORY
INSTALLED LINEAR TEMPERATURE LIMIT
CONTROL IF THE HEATER WIDTH > 72".
16. NEVER USE ALUMINUM CONDUCTORS.
Use copper conductors only for all incoming
wiring.
17. NEVER INSTALL A STANDARD HEATER
OUTDOORS WITHOUT MAKING SPECIAL
PROVISIONS TO PROTECT THE HEATER
AND CONTROL BOX FROM THE ELEMENTS.
18. NEVER BUNDLE, TIE OR WRAP POWER WIRING.
The wire could overheat or the insulation could
breakdown.
19. NEVER USE A DIFFERENT VOLTAGE AND/OR
PHASE THAN WHAT IS LISTED ON THE HEATER
NAMEPLATE LABEL.
The duct heater is to be used only at the voltage
and phase that is listed on the nameplate label.
Note: An airflow switch only proves that airflow exist
(a differential in static pressure), not that the
minimum air velocities and proper air
distribution for the duct heater exist.
AIR HANDLER
HEATER
FIG. 5
FIG. 6
HEATER
HUMIDIFIER
AIR FILTER
HEATER
FIG. 7
48" MIN.
48" MIN.
CORRECT INCORRECT
CORRECT INCORRECT
FIG. 8
FIG. 9
FIG. 10
PAGE 2 OF 2
DUCT
DUCT
DUCT
VIEW OF A HORZONTIAL DUCT.
NOTE: ALL FIGURES ARE SHOWING A TOP
INCORRECT
48" MIN.
7. Always locate the heater
at least 48" from any
canvas duct connector
or transition section
for change in duct size.
If connecting to round
duct, install heater in a
rectangular duct section.
Use round-to-rectangular
pyramidal transitions to
connect round duct to
rectangular duct. Always
locate the heater at least
48" from any transition
section for change in duct
size. Follow installation
guidelines given in manual
and in accordance with
SMACNA guidelines (see
Figure 3.1.3)
8. Always locate the heater
at least 48" downstream
from an air handler. (See
Figure 3.1.4)
9. Always locate the heater at
least 48" upstream from
an humidifier. (See Figure
3.1.5)
10. Always locate the heater
at least 48" downstream
from an air filter. (See
Figure 3.1.6)
PLACEMENT
FIGURE 3.1.3 PLACEMENT: TRANSITION REQUIREMENTS
FIGURE 3.1.5 PLACEMENT: HUMIDIFIER REQUIREMENTS
FIGURE 3.1.6 PLACEMENT: AIR FILTER REQUIREMENTS
FIGURE 3.1.4 PLACEMENT: DOWNSTREAM REQUIREMENTS
1.800.627.449918
EK-Series Electric Duct Heater
ACCESSORY
DUCT W/ INTERNAL INSULATION
DUCT W/ EXTERNAL INSULATION
10. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR FILTER.
(see fig. 7)
11. NEVER INSTALL A STANDARD HEATER INTO A
DUCT WITH AN INTERNAL OBSTRUCTION.
Due to the fact that an obstruction can block
airflow at the temperature limit controls and
element terminations. If this situation exist, it
can be corrected by using a heater with a
recessed control box and reduced wrapper size.
This situation is common with internally insulated
ducts. (see fig. 8)
12. NEVER INSULATE THE EXTERIOR OF THE
CONTROL BOX.
The control box must be completely accessible
and located where ventilation can be provided at
all times. (see fig. 9)
13. NEVER INSTALL A HEATER NEAR A DOUBLE
BLOWER OUTLET.
A heater must be installed far enough away from
a double blower outlet that even and proper
airflow is present or separate duct heaters
placed in the duct runouts of each blower. (all
installation must conform with the heater
installation instructions.) (see fig. 10)
14. NEVER INSTALL A HEATER LESS THAN 48"
FROM ANY FAN.
Mounting a heater any closer than 48" to a fan
will result in uneven airflow.
15. ORDER THE HEATER WITH THE FACTORY
INSTALLED LINEAR TEMPERATURE LIMIT
CONTROL IF THE HEATER WIDTH > 72".
16. NEVER USE ALUMINUM CONDUCTORS.
Use copper conductors only for all incoming
wiring.
17. NEVER INSTALL A STANDARD HEATER
OUTDOORS WITHOUT MAKING SPECIAL
PROVISIONS TO PROTECT THE HEATER
AND CONTROL BOX FROM THE ELEMENTS.
18. NEVER BUNDLE, TIE OR WRAP POWER WIRING.
The wire could overheat or the insulation could
breakdown.
19. NEVER USE A DIFFERENT VOLTAGE AND/OR
PHASE THAN WHAT IS LISTED ON THE HEATER
NAMEPLATE LABEL.
The duct heater is to be used only at the voltage
and phase that is listed on the nameplate label.
Note: An airflow switch only proves that airflow exist
(a differential in static pressure), not that the
minimum air velocities and proper air
distribution for the duct heater exist.
AIR HANDLER
HEATER
FIG. 5
FIG. 6
HEATER
HUMIDIFIER
AIR FILTER
HEATER
FIG. 7
48" MIN.
48" MIN.
CORRECT INCORRECT
CORRECT INCORRECT
FIG. 8
FIG. 9
FIG. 10
PAGE 2 OF 2
DUCT
DUCT
DUCT
VIEW OF A HORZONTIAL DUCT.
NOTE: ALL FIGURES ARE SHOWING A TOP
INCORRECT
48" MIN.
DUCT W/ INTERNAL INSULATION
DUCT W/ EXTERNAL INSULATION
10. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR FILTER.
(see fig. 7)
11. NEVER INSTALL A STANDARD HEATER INTO A
DUCT WITH AN INTERNAL OBSTRUCTION.
Due to the fact that an obstruction can block
airflow at the temperature limit controls and
element terminations. If this situation exist, it
can be corrected by using a heater with a
recessed control box and reduced wrapper size.
This situation is common with internally insulated
ducts. (see fig. 8)
12. NEVER INSULATE THE EXTERIOR OF THE
CONTROL BOX.
The control box must be completely accessible
and located where ventilation can be provided at
all times. (see fig. 9)
13. NEVER INSTALL A HEATER NEAR A DOUBLE
BLOWER OUTLET.
A heater must be installed far enough away from
a double blower outlet that even and proper
airflow is present or separate duct heaters
placed in the duct runouts of each blower. (all
installation must conform with the heater
installation instructions.) (see fig. 10)
14. NEVER INSTALL A HEATER LESS THAN 48"
FROM ANY FAN.
Mounting a heater any closer than 48" to a fan
will result in uneven airflow.
15. ORDER THE HEATER WITH THE FACTORY
INSTALLED LINEAR TEMPERATURE LIMIT
CONTROL IF THE HEATER WIDTH > 72".
16. NEVER USE ALUMINUM CONDUCTORS.
Use copper conductors only for all incoming
wiring.
17. NEVER INSTALL A STANDARD HEATER
OUTDOORS WITHOUT MAKING SPECIAL
PROVISIONS TO PROTECT THE HEATER
AND CONTROL BOX FROM THE ELEMENTS.
18. NEVER BUNDLE, TIE OR WRAP POWER WIRING.
The wire could overheat or the insulation could
breakdown.
19. NEVER USE A DIFFERENT VOLTAGE AND/OR
PHASE THAN WHAT IS LISTED ON THE HEATER
NAMEPLATE LABEL.
The duct heater is to be used only at the voltage
and phase that is listed on the nameplate label.
Note: An airflow switch only proves that airflow exist
(a differential in static pressure), not that the
minimum air velocities and proper air
distribution for the duct heater exist.
AIR HANDLER
HEATER
FIG. 5
FIG. 6
HEATER
HUMIDIFIER
AIR FILTER
HEATER
FIG. 7
48" MIN.
48" MIN.
CORRECT INCORRECT
CORRECT INCORRECT
FIG. 8
FIG. 9
FIG. 10
PAGE 2 OF 2
DUCT
DUCT
DUCT
VIEW OF A HORZONTIAL DUCT.
NOTE: ALL FIGURES ARE SHOWING A TOP
INCORRECT
48" MIN.
DUCT W/ INTERNAL INSULATION
DUCT W/ EXTERNAL INSULATION
10. ALWAYS LOCATE THE HEATER AT LEAST 48"
DOWNSTREAM FROM AN AIR FILTER.
(see fig. 7)
11. NEVER INSTALL A STANDARD HEATER INTO A
DUCT WITH AN INTERNAL OBSTRUCTION.
Due to the fact that an obstruction can block
airflow at the temperature limit controls and
element terminations. If this situation exist, it
can be corrected by using a heater with a
recessed control box and reduced wrapper size.
This situation is common with internally insulated
ducts. (see fig. 8)
12. NEVER INSULATE THE EXTERIOR OF THE
CONTROL BOX.
The control box must be completely accessible
and located where ventilation can be provided at
all times. (see fig. 9)
13. NEVER INSTALL A HEATER NEAR A DOUBLE
BLOWER OUTLET.
A heater must be installed far enough away from
a double blower outlet that even and proper
airflow is present or separate duct heaters
placed in the duct runouts of each blower. (all
installation must conform with the heater
installation instructions.) (see fig. 10)
14. NEVER INSTALL A HEATER LESS THAN 48"
FROM ANY FAN.
Mounting a heater any closer than 48" to a fan
will result in uneven airflow.
15. ORDER THE HEATER WITH THE FACTORY
INSTALLED LINEAR TEMPERATURE LIMIT
CONTROL IF THE HEATER WIDTH > 72".
16. NEVER USE ALUMINUM CONDUCTORS.
Use copper conductors only for all incoming
wiring.
17. NEVER INSTALL A STANDARD HEATER
OUTDOORS WITHOUT MAKING SPECIAL
PROVISIONS TO PROTECT THE HEATER
AND CONTROL BOX FROM THE ELEMENTS.
18. NEVER BUNDLE, TIE OR WRAP POWER WIRING.
The wire could overheat or the insulation could
breakdown.
19. NEVER USE A DIFFERENT VOLTAGE AND/OR
PHASE THAN WHAT IS LISTED ON THE HEATER
NAMEPLATE LABEL.
The duct heater is to be used only at the voltage
and phase that is listed on the nameplate label.
Note: An airflow switch only proves that airflow exist
(a differential in static pressure), not that the
minimum air velocities and proper air
distribution for the duct heater exist.
AIR HANDLER
HEATER
FIG. 5
FIG. 6
HEATER
HUMIDIFIER
AIR FILTER
HEATER
FIG. 7
48" MIN.
48" MIN.
CORRECT INCORRECT
CORRECT INCORRECT
FIG. 8
FIG. 9
FIG. 10
PAGE 2 OF 2
DUCT
DUCT
DUCT
VIEW OF A HORZONTIAL DUCT.
NOTE: ALL FIGURES ARE SHOWING A TOP
INCORRECT
48" MIN.
11. Never install a standard
heater into a duct with
an internal obstruction.
Due to the fact that an
obstruction can block
airflow at the temperature
limit controls and element
terminations. If this
situation exists, it can
be corrected by using a
heater with a recessed
control box and reduced
wrapper size. This
situation is common with
internally insulated ducts.
(see Figure 3.1.7)
12. Never insulate the exterior
of the control box. The
control box must be
completely accessible and
located where ventilation
can be provided at all
times. (see Figure 3.1.8)
13. Never install a heater
near a double blower
outlet. A heater must
be installed far enough
away from a double
blower outlet that even
and proper airflow is
present or separate duct
heaters placed in the duct
runouts of each blower.
(all installation must
conform with the heater
installation instructions.)
(see Figure 3.1.9)
14. Never install a heater
less than 48" from any
fan. Mounting a heater
any closer than 48" to a
fan will result in uneven
airflow.
15.Never use aluminum
conductors. Use copper
conductors only for all
incoming wiring.
16. Never install a standard
heater outdoors without
making special provisions
to protect the heater
and control box from the
elements.
17. Never bundle, tie or
wrap power wiring. The
wire could overheat or the
insulation could breakdown.
18. Never use a different
voltage and/or phase
than what is listed on the
heater nameplate label.
The duct heater is to be
used only at the voltage and
phase that is listed on the
nameplate label.
PLACEMENT
FIGURE 3.1.7 PLACEMENT: OBSTRUCTION REQUIREMENTS
FIGURE 3.1.8 PLACEMENT: CONTROL BOX REQUIREMENTS
FIGURE 3.1.9 PLACEMENT: DOUBLE BLOWER REQUIREMENTS
191.800.627.4499
EK-Series Electric Duct Heater ACCESSORY
4.0 ELECTRICAL DATA
4.1 TYPICAL CONTACTOR POWER CIRCUITRY
(Only power circuit shown, safety devices etc., omitted)
TWO LINE BREAK
Heating power is completely disconnected
by breaking both sides of the power
source. All ungrounded power conductors
are disconnected.
All ungrounded conductors disconnected.
Both WYE and Delta configurations shown.
DISCONNECTING TYPE:
SINGLE PHASE
DELTA
WYE
SINGLE
PHASE
SUPPLY
HEATING
ELEMENT
CONTACTOR
SINGLE
PHASE
SUPPLY
CONTACTOR
HEATING
ELEMENT
CONTACTOR
DISCONNECTING TYPE:
SINGLE LINE BREAK
This type would be disconnecting for
120V and 277V, providing the contactor
opens the ungrounded line.
SINGLE PHASE
Heating elements, namely those used in
three phase, balanced, configurations
are factory wired, as manufacturers
standard in two basic configurations
delta or WYE.
THREE WIRE DELTA CONNECTION
1. Element Voltage = Line Voltage
2. Phase Currents In = lL1 = lL2 = lL3
3. Voltage measured between any two
power legs (L1 to L2 etc.) should be
equal to the three phase line
voltage.
THREE WIRE WYE CONNECTION
1. Element Voltage = Line Voltage
1.73
2. Phase Currents In = lL1 = lL2 = lL3
3. Voltage measured between any
two power legs (L1 to L2 etc.)
should be equal to the three phase
line voltage.
HEATING
ELEMENT(S)
LINE
VOLTAGE
THREE PHASESINGLE PHASE
Element Voltage = Line Voltage
480V for illustration only
lL1
lL3
lL2
L1
480V
480V
480V
L2
L3
lL1
lL3
lL2
480V
480V
480V
L1
L2
L3
SINGLE
PHASE
SUPPLY
4.2 HEATING ELEMENT WIRING CONFIGURATIONS AND PROPERTIES
ELECTRICAL DATA
FIGURE 4.1.0 TYPICAL CONTACTOR POWER CIRCUITRY
FIGURE 4.2.0 HEATING ELEMENT WIRING PROPERTIES
THREE PHASE
1.800.627.449920
EK-Series Electric Duct Heater
ACCESSORY
4.3 HEATER WIRING SCHEMATICS
FIGURE 4.3.1 SINGLE PHASE SCR HEATER WIRING
FIGURE 4.3.0 SINGLE PHASE ON-OFF HEATER WIRING
ELECTRICAL DATA
NOTE: See low
voltage control
connections, pages
23-25, for external
control wiring.
NOTE: See low
voltage control
connections, pages
23-25, for external
control wiring.
Other manuals for EK Series
1
Table of contents
Popular Electric Heater manuals by other brands
Flame & Shade
Flame & Shade SHELDON owner's manual
Harvia
Harvia QR70 Instructions for installation and use
Daikin
Daikin DRC090 installation instructions
Thermo Sphere
Thermo Sphere QGW08-608 manual
Solaire
Solaire alpha user manual
Intertec Data Systems
Intertec Data Systems CP MEGATHERM D.A HI series operating instructions
