E
LECTRIC
D
UCT
H
EATER
•
I.O.M.
14
Electric Duct Heater IOM • ©June, 2001 • Environmental Technologies, Inc.
CAUTION: Lethal voltages are present in the heater control enclosure. Use extreme caution when
taking measurements in these units. Always remove power before removing or re-applying any
connections.
1. Before applying power, verify wiring matches diagram in cover of heater control enclosure, and that
correct line voltage has been wired to heater line block. NOTE: Polarity of the 24 VAC signal is
important. If incorrect, controller will not work, and, in some cases, may be damaged.
2. Verify 24 VAC +15% or 10% between terminals 15 and 16 of the vernier controller (ETGC8VP).
3. 5V or 0.25V between the +5Vand COM test loops on controller. These are located
approximately in the center of the board. If zero, check fuse.
4. LED should be blinking in two second intervals (one second on, one second off). If LED stays on or
off, controller is damaged and must be replaced.
5. If LED flashes rapidly (several times a second), non-volatile memory has been scrambled, causing the
controller to shut down as a precautionary measure. The non-volatile memory (8 pin, socketed IC
labeled 93C56) may be replaced by one programmed at the factory. Contact your ETI representative
and order part number 13807. Make sure to relay all the information on the controllers identification
tag, as this will be used to program the correct configuration.
6. The controller is set for direct acting, i.e., low signal is off, high signal is on. Apply low signal to J8,
terminals 3 (+) and 4 (-), and verify heat is off. If SSR stage remains on, remove wires from J2. If SSR
stays on refer to SSR Checkout List; otherwise, replace controller. If a relay stage stays on, remove
wire for that stage from its terminal (7 through 14). If relay stays on, check heater wiring; otherwise,
replace controller.
7. Apply high signal (e.g., 10 VDC, 20 mA, etc.) to J8, terminals 3 (+) and 4 (-), and verify all heat stages
are on. If SSR stays off, refer to SSR Checkout List. If a relay stage stays off, remove wire for that
stage from its terminal (7 through 14) and touch to terminal 15. If relay stays off, check heater wiring;
otherwise, replace controller.
REPLACEMENT PARTS
• Replacement parts should be ordered from the local ENVIRO-TEC
®
representative. Factory replacement
parts must be used to maintain agency listings. Any substitutions and/or modifications not authorized
by the factory will void the unit warranty, the agency listing, and could result in personal injury and/or
property damage.
When ordering parts, the following information must be supplied to ensure proper part identification:
1) Complete unit catalog number on unit label
2) Complete parts description, including any identification numbers
To find your nearest ENVIRO-TEC
®
representative, visit our web site at
www.enviro-tec.com
or contact
the factory at 727-541-3531.
V
ERNIER
H
EAT
C
ONTROL
T
ROUBLESHOOTING
G
UIDE
