Trane IntelliPak SCWF 20 Installation, Operation And Maintenance Manual page 107

Category Diagnostic
A "Lockout" request is sent to the compressor staging control function. And a fail-safe function in the MCM will cause all MCM
Reaction
outputs to be zeroed and de-energized.
Reset
(PAR) An automatic reset occurs after communication has been restored.
Required
Mode Input Failure
The RTM mode input is out of range.
Problem
Sensor resistance should be between 1 ohm and 40 ohms. If so, check field/unit wiring between sensor and RTM.
Check
Reason for
The mode input signal on the RTM is out of range (resistance < 1 ohm or resistance > 40 ohms).
Diagnostic
Controls
The system mode reverts to the default (HI set) system mode.
Reaction
Reset
(INFO) An automatic reset occurs after the mode input returns to its allowable range for 10 seconds.
Required
N
NSB Panel Zone Temperature Sensor Failure
The NSB panel's zone temp sensor input is out of range. (This input is at the NSB panel, not on the unit itself).
Problem
If have an external sensor connected to the NSB panel zone sensor input, then the internal NSB panel zone sensor should be
Check
disabled. Verify sensor resistance. If in valid range, check wiring between the sensor and NSB panel.
NSB Panel Comm Failure
The RTM has lost communications with the night setback panel (programmable zone sensor).
Problem
Field/unit wiring between RTM and NSB Panel.
Check
Reason for
The RTM has lost communication with the NSB panel.
Diagnostic
The unit reverts to the next lower priority mode switching source (typically the HI default mode). If the NSB panel zone sensor
Controls
is the designated sensor source for any functions, those functions are disabled.
Reaction
Reset
(PAR) An automatic reset occurs after communication has been restored.
Required
O
O/A Humidity Sensor Failure
The outside air humidity sensor data is out of range.
Problem
Check field/unit wiring between the sensor and RTM.
Check
Reason for
The unit is reading a signal that is out of range for the outside air humidity sensor (humidity < 5% or humidity > 100%).
Diagnostic
Controls
The economizer enable enthalpy function reverts to dry-bulb temperature changeover ("Level 1") control.
Reaction
Reset
(PAR) An automatic reset occurs after the OA humidity input returns to its allowable range for 10 seconds.
Required
O/A Temp. Sensor Failure
The outside air temperature sensor input is out of range.
Problem
Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between sensor
Check
and RTM.
Reason for
The unit is reading a signal that is out of range for the outside air temperature input on the RTM (temp. < -55°F or temp > 209°
Diagnostic F).
SCXF-SVX01Q-EN
D D i i a a g g n n o o s s t t i i c c s s
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