Troubleshooting guide

I.O.M. • ELECTRIC DUCT HEATER
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.