York YPAL 060 manual Supply Air Temperature Cooling Alarm, Supply Air Temperature Heating Alarm

Supply Air Temperature Cooling Alarm (38)

The Unit Controller compares the supply air temperature to the “SUPPLY AIR TEMP ALARM FOR COOLING” and initiates the alarm based on the following criteria:

•All the stages of cooling have been on for 10 or more minutes.

•The supply air temperature is 20 or more degrees above the “SUPPLY AIR TEMP ALARM FOR COOLING” set point for 10 minutes.

•The outdoor air is not 20.0° F or more warmer then the “SUPPLY AIR TEMP ALARM FOR COOLING” set point.

•The outdoor air damper is not open more then 20%.

Supply Air Temperature Heating Alarm (39)

The Unit Controller compares the supply air temperature to the “SUPPLY AIR TEMP ALARM FOR HEATING” and initiates the alarm based on the following criteria:

•All the stages of heating have been on for 10 or more minutes.

•The supply air temperature is 20 or more degrees below the “SUPPLY AIR TEMP ALARM FOR HEATING” set point for 10 minutes.

•The outdoor air is not 20.0° F or more cooler then the “SUPPLY AIR TEMP ALARM FOR HEATING” set point.

•The outdoor air damper is not open more then 20%.

Economizer Minimum Position Alarm (40)

Prior to declaring this fault the Unit Controller checks the outside air temperature and the economizer position. If the outside air temperature is more then 20.0° F warmer then the set point and the economizer is open more then 20%, the Unit Controller will close the economizer for 10 minutes and then check the supply air temperature. If the SAT falls below the set point, the control will declare an economizer minimum position alarm. The Unit Controller will keep the economizer closed until the end of the cooling cycle. It will then return the economizer damper to its minimum position.

FORM 100.50-NOM6 (1207)

Space Temperature Trending Alarm (41)

This alarm will be generated based on the following criteria:

•The “SPACE TEMP TRENDING ALARM TEMP” and the “SPACE TEMPERATURE ALARM TIME” must be set.

•The unit has been in a given mode of operation for 10 minutes.

•The temperature is below or above the space temperature set point and the trend continues to be away from the space temperature set point and the “SPACE TEMP TRENDING ALARM TIME” has expired.

Duct Static Low Pressure Alarm (42)

This alarm is initiated on a VAV unit if after 35 seconds of supply fan operation the duct static pressure is not equal to or greater then 0.05” WC. When the alarm becomes active the unit stops all operation and locks out. This can be the result of a faulty Duct Static Pressure Transducer or in the transition from an unoccupied to occupied mode if the VAV boxes are wide open.

To check the operation of the duct static transducer measure the VDC input between terminal DP+ wire 337 at the P21 connector and terminal DP- wire 338 at the P21 connector. Compare the voltage verses the duct pressure the control indicates to Table 8-2 in this section of the manual. Also verify that 24 VAC is present between terminals “COM” and “EXC” at the duct static transducer.

Hot Water Coil Freeze Alarm (43)

The alarm indicates the hydronic freeze stat switch has opened. The 24 VAC source originates at the terminal FSP, wire 389. The input to the control originates at terminal FSI, wire 388.

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JOHNSON CONTROLS 167