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C4 Manual Rev 7.5.2
“LO” indicates that the reported temperature was 20-50/C below the System
Operating Range. “HI” indicates that the reported temperature was 20-50/C
above the System Operating Range. The number following the p is the number of
the probe that reported the excessive temperature.
In the event that the control temperature reported by the active control probe is
more than 50/C beyond the System Operating Range, the controller will presume
that the operation of the probe has been compromised by an open or shorted
circuit. The controller will turn off all heating and cooling and stop controlling.
Blowers will be left in the condition determined by setup parameter F15 (Blower
shut-off mode). The controller display will show
p1 err p1 -err
The minus sign in the display indicates that the reported temperature was below
the System Operating Range and the absence of the minus sign indicates that it
was above the System Operating Range.
Note that because the C4 will report a hi or lo condition and stop controlling
for an error of 20-50/C, the only events that will typically trigger an err or -
err condition is a instantaneous failure of the sensing circuit, most likely an
open circuit (err) or short (-err ).
3.6.1 Effect of Probe Correction on Out of Range Shutdown
Any adjustments to the probe readings made by the Software Probe Correction
feature (See Section 3.8) will not affect system over/under temperature shutdown
operations. The raw (uncorrected) probe readings for the current active control
probe(s) are used for the system health monitoring.
3.6.2 Probe Out of Range Shutdown Reported in Error/Status String
Any Probe Out of Range Shutdown will set a bit in Byte 03 of the Error/Status
String. See Section 7.8.3 for specific bit assignments.
3.6.3 Clearing a Probe Out of Range Shutdown