York YPAL 051 User Manual

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165
JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
8
Supply Air Temperature Sensor Alarm (20)
This alarm indicates the supply air temperature input is 
either open or shorted.  The display will show a value 
of –40.0° F.  The supply air temperature input is at 
SAT+ and SAT- of the P11 connector.  To trouble shoot 
compare the resistance of the input to the actual supply 
air temperature using Table 8-1.
Return Air Temperature Sensor Alarm (21)
This alarm indicates the return air temperature input is 
either open or shorted.  The display will show a value 
of –40.0° F.  The return air temperature input is at 
RAT+ and RAT- of the P11 connector.  To trouble shoot 
compare the resistance of the input to the actual return 
air temperature using Table 8-1.
Outdoor Air Temperature Sensor Alarm (22)
This alarm indicates the outdoor air temperature input 
is either open or shorted.  The display will show a 
value of –40.0° F.  The outdoor air temperature input 
is at OAT+ and OAT- of the P11 connector.  To trouble 
shoot compare the resistance of the input to the actual 
outdoor air temperature using Table 8-1.
Dirty Filter Switch Alarm (23)
This alarm will have no effect on the operation of the 
unit.  The alarm indicates the dirty fi lter switch contacts 
have closed indicating the pressure drop across the fi lters 
is above the setting of the switch.  The 24 VAC output 
to the switch is at terminal FILT wire 391 of the P22 
connector and the input to the control is at terminal FILT 
wire 390 of the P22 connector.
Supply Fan Air Proving Switch (24)
This alarm indicates there was a call for supply fan 
operation and after 90 seconds of supply fan operation 
the switch did not close.  The Unit Controller will retry 
the fan output every 30 minutes for three retires.  If after 
the three retries the Unit Controller will lockout heating 
and cooling operation.
On a VAV unit the Unit Controller will also use the duct 
static pressure input to qualify supply fan operation.  
If the Unit Controller reads more then 0.05" WC it 
will continue to identify the alarm but allow the unit 
to operate.
The 24 VAC output to the switch is at terminal APS wire 
412 of the P11 connector and the input to the control is 
at terminal APS wire 411 of the P11 connector.
Supply Fan Air Proving Switch Closed Alarm (25)
This alarm indicates the call for supply fan operation 
has been terminated and after 90 seconds of supply fan 
operation the switch remained closed.  The control will 
fl ash the alarm but allow the unit to operate normally.
The 24 VAC output to the switch is at terminal APS wire 
412 of the P11 connector and the input to the control is 
at terminal APS wire 411 of the P11 connector.
Microelectronics Failure Alarm (26)
This alarm indicates a problem with the Unit Controller 
microelectronics has occurred and the Unit Controller 
is operating on default values.  Try recycling power 
to the control.  If the fault reappears replace the Unit 
Controller.
Microelectronics Failure Alarm (27)
This alarm indicates a problem with the Unit Controller 
microelectronics has occurred and the Unit Controller is 
shut down.  Try recycling power to the control.  If the 
fault reappears replace the Unit Controller.
Supply Fan Overload Alarm (28)
The Unit Controller monitors this circuit anytime 
the supply fan is operative.  If this input is lost for 
50 milliseconds, the control will shut down all unit 
operation.  If the voltage input does not return in 5-
minutes the control will turn on the alarm.
If the voltage returns the Unit Controller will log the 
fi rst incident and track the run time.  If the switch opens 
three times in a two-hour period the Unit Controller will 
shut down the unit.
The 24 VAC output to the switch is at terminal FOVR 
wire 404 of the P16 connector and the input to the control 
is at terminal FOVR wire 403 of the P16 connector.