102
SCXF-SVX01Q-EN
Table 49. Potential unit issues and solutions (continued)
Problem Possible Cause Remedy
Excess dirt in unit Missing filters Filter bypass Replace filters Reduce filter bypass
Microbial growth (mold) Standing water in drain pan See "Standing water in drain pan" above
Additional Diagnostic Resources
Refer to the Self-Contained Programming Guide, PKG-
SVP01, for specific unit programming and
troubleshooting information. In particular, reference
the “Service Mode Menu” and “Diagnostic Menu”
sections in the programming guide. Refer to the
following text for general diagnostic and
troubleshooting procedures.
Category Diagnostic
A
Auto Reset S/A Static Pressure Limit
Problem The supply air static pressure went too high. Reason for Diagnostic: The S/A static pressure exceeded the S/A static pressure
limit setpoint for at least one second continuously.
Controls
Reaction
A “supply air pressure shutdown” signal is sent to the following functions:
• Compressor staging control
• Economizer actuator control
• Heat operation
• Supply fan control,
• VFD control
• Exhaust fan control
• Exhaust actuator control
Reset
Required
(PAR)The supply fan is not allowed to restart for 15 seconds after the diagnostic occurs. An auto reset will also occur if the unit
cycles out of occupied mode and back.
C
CO2 Sensor Failure
Problem The VCM CO2 sensor input signal is out of range.
Check Check field/unit wiring between sensor and VCM.
Reason for
Diagnostic
The unit is reading a signal that is out of range for the CO2 sensor transducer input.
Controls
Reaction
The CO2 reset function disables.
Reset
Required
(PAR) An automatic reset occurs after the CO2 sensor transducer input receives a signal that is within range for ten continuous
seconds.
Compressor Contactor Fail—Circuit 1, 2, 3, or 4
Problem
The compressor contactor for Ckt. 1, 2, 3, or 4 has malfunctioned.
Reason for
Diagnostic
The circuit compressor proving input is detected closed continuously for more than three seconds while neither compressor
output on that circuit closes.
Controls
Reaction
A “lockout ckt #1, 2, 3, or 4” request is issued to the compressor staging control function.
Reset
Required
(PMR) A manual reset is required after the diagnostic is set. It can be reset by the HI or Tracer Summit.
Compressor Trip—Ckt 1, 2, 3, or 4
Problem
The compressor ckt #1, 2, 3, or 4 has tripped.
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