Tracer
®
ZN.010
and ZN.510
56
UNT-IOM-6
Table 18. Electric Heat Not Operating
Probable Cause
Explanation
Normal operation
The controller cycles electric heat on and off to meet the unit capacity require-
ments.
Requested mode: off
It is possible to communicate the operating mode (such as off, heat, cool)
to the controller. When off is communicated to the controller, the units shuts off
the electric heat.
Communicated disable Numerous communicated requests may disable electric heat, including an
auxiliary heat enable input and the heat/cool mode input. Depending on the
state of the communicated request, the unit may disable electric heat.
Manual output test
The controller includes a manual output test sequence that verifies analog and
binary output operation and associated output wiring. However, based on the
current step in the test sequence, the electric heat may not be on. Refer to the
Manual Output Test section on page 51.
Diagnostic present
A specific list of diagnostics affects electric heat operation. For more informa-
tion, see the Diagnostics section on page 50.
Unit configuration
The controller must be properly configured based on the actual installed end
devices and application. When the unit configuration does not match the actual
end device, the electric heat may not work properly.
No power to the
If the controller does not have power, electric heat does not operate. For the
controller
controller to operate normally, a 24VAC input voltage must be applied. When
the green LED is off continuously, the controller does not have sufficient power
or has failed.
Unit Wiring
The wiring between the controller outputs and the electric heat contacts must
be present and correct for normal electric heat operation. Refer to the typical
unit wiring diagrams in the Appendix of this manual.
