Diagnostics; Resetting Diagnostics - Trane Tracer AH540 Setup And Operation

CNT-SVX05B-EN

Diagnostics

Table 63 on page 91 describes the diagnostics that can be generated by
the Tracer AH540/541 controller. There are three types of diagnostics:
Critical—The controller shuts down the unit to prevent possible damage.
•
The controller cannot operate until the diagnostic condition is corrected.
Service required—The controller disables certain sequences of opera-
•
tion while attempting to maintain unit operation. For example, if the
mixed-air temperature sensor fails or is not wired, the controller dis-
ables economizer operation.
• Informational—The controller operates normally.

Resetting diagnostics

Diagnostics that cause the unit to shutdown or disable certain operations
are either latching or non-latching. Latching diagnostics require manual
resetting. Non-latching diagnostics automatically clear when the condi-
tion that caused the diagnostic is solved.
Resetting is similar to cycling power to the unit. Resetting clears any
latching diagnostics and allows the controller to restart the air-handling
unit, if it is running normally. If the condition that caused the latching
diagnostic is still present, however, the controller immediately shuts
down the unit.
You can reset diagnostics in a variety of ways:
Manual output test
•
• Cycling power to the controller
Building automation system
•
Rover service tool
•
Any communicating device able to access the diagnostic reset input of
•
the controller
Zone sensor fan mode switch
•
Operator display
•
Manual output test
Use the Test button on the controller during installation to verify proper
end-device operation or during troubleshooting. When you press the Test
button, the controller exercises all outputs in a predefined sequence. The
first and last outputs of the sequence reset the controller diagnostics. See
"Performing a manual output test" on page 84.
Cycling power
When the 24 Vac power to the controller is turned Off and then On, the
unit cycles through a power-up sequence (see "Power-up sequence" on
page 40). By default, the controller attempts to reset all diagnostics dur-
ing this sequence.
Diagnostics
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