I.O.M. •
E
LECTRIC
D
UCT
H
EATER
9
Environmental Technologies, Inc. •©June, 2001 • Electric Duct Heater IOM
COMMON SYMPTOMS
POSSIBLE CAUSE
REMEDY
Heater Does Not Operate
No Power
• Check disconnect
No Control Voltage
• Check control signal (i.e. 24volt)
• Check transformer and transformer
fusing (if applicable), replace if necessary
Blown Fuse
• Replace fuse
Open Limit (primary or secondary)
• Replace limits or reset as applicable
• Check for continuity across limit to
determine if open, replace as necessary
Airflow Incorrect Direction
• Check sensing tube, rotate if needed
(see Figure 6 above)
Low Airflow Static Pressure
• Increase airflow
Damaged Elements
• Check for open or damaged
elements and replace as necessary
Low or High Temperature
Incompatible Thermostat or Controller • Check wiring
Rise
• Check for compatibility
Problems with Additional Stages
• Check location of thermostat; may be
installed in a ”too hot” or ”too cold”
location
• Check contactors for open coil
• Check for damaged elements
Incorrect CFM
• Check for blocked duct or location
of heater
Short Cycling
Improper Airflow
• Check for even airflow across
the face of element section
• Check for blocked duct
• Check for dirty filters
Low CFM
• See remedies for “Improper Airflow“
• Check air velocity
Heater w/SSR
Incorrect Signal Applied
• Verify signal input
Does Not Operate
• See page 8 (Troubleshooting Guide)
Interface Board Fuse Blown
• Replace fuse
(See page 8 [Troubleshooting Guide]
for correct size and type)
T
ROUBLESHOOTING
• Check installation instructions and wiring diagrams to ensure heater is wired and installed properly.
AMPERE READING PER KW
VOLTAGE/PHASE
AMPERES/KW
120 / 1
8.33
208 / 1
4.80
240 / 1
4.16
277 / 1
3.61
480 / 1
2.08
208 / 3
2.77
240 / 3
2.40
480 / 3
1.202
Figure 6
Airflow Switch Probe Reversal
Airflow switch probe is installed in accordance with the specifi-
cation. If application dictates opposite airflow, rotate the probe
180°. Directional arrow is stamped on airflow sensing probe.
DOES NOT APPLY TO VERTICAL UNITS.
