York YCAS0130 manual Micro Panel Contents, Pump Down, Incorrect Refrigerant Warning

Micro Panel Contents

The U13 RTC chip should be replaced as soon as possible with Part # 031-00955-000. Otherwise, the chiller will shutdown and lose all programmed points, and require a MANUAL OVERRIDE restart, if a power failure occurs.

Pump Down:

S Y S	1	P U M P I N G	D O W N
S Y S	2	P U M P I N G	D O W N

This message indicates that both refrigerant systems are in a pumpdown cycle. Pumpdown display messages oc- cur on shutdowns where the cooling load has been met, or when a system switch is turned OFF. Note that only one compressor could be pumping down, as shown in the following display:

S Y S	1	P U M P I N G	D O W N
S Y S	2	C O M P R U N N I N G

See Section 1.18 (page 132) for details of pumpdown control.

Incorrect Refrigerant Warning:

R E P R O G R A M T Y P E O F R E F R I G E R A N T T O R U N

The incorrect Refrigerant Warning will occur if the DIP Switch setting for refrigerant type and the type programmed into the micro “at the factory” under the Service Mode are not the same. This message will be displayed until the non-programmable “factory” pro- grammed refrigerant type and DIP Switch setting agree. See Page 179 for Service Mode programming.

Power Failure Warning:

The Power Failure Warning will only be displayed on “power restoration” after a “power loss,” if manual re- start on power failure is selected under the PROGRAM key (page 170). If manual restart on power failure has been selected, the following warning message is dis- played indefinitely on power restoration and the chiller will not run until the UNIT Switch is cycled OFF-and-on to restart the unit. This safety is available for users who desire a chiller lock-out on power failure.

This is typically not a desirable feature to select. Most applications re- quire auto-reset after a power failure. Therefore, "Automatic" is typically selected and programmed under the PROGRAM key. See page 170.

FORM 201.19-NM1 (204)

! ! P O W E R F A I L U R E ! !

C Y C L E U N I T S W I T C H

When this message appears, the chiller will not run and the Unit Switch must be cycled OFF and ON to start the unit.

Incorrect Unit Type Warning:

R E P R O G R A M

U N I T T Y P E

The incorrect Unit Type Warning will occur if the DIP Switch setting for unit type and the type programmed into the micro "at the factory" are not the same. This message will be displayed until the "factory" pro- grammed unit type and DIP Switch setting agree. See Page 179 for Service Mode Programming.

2.4ANTICIPATION CONTROL STATUS MESSAGES

Anticipation controls are built into the software to prevent safety shutdowns by automatically overriding the temperature controls, if system conditions approach safety thresholds. This avoids total loss of cooling resulting from a lockout by a safety control.

Anticipation controls monitor discharge pressure, motor current and suction temperature for each compressor and if maximum limits are approached, the slide valve loading of the respective compressor will be reduced to avoid exceeding the limit.

Displays of anticipation safety control messages and their meanings are as follows:

Discharge Pressure Limiting:

S Y S	#	D S C H	L	I M I	T	I	N G
S Y S	#	D S C H	L	I M I	T	I	N G

Discharge Pressure Limiting takes effect when compressor discharge pressure nears the point at which the high pressure cutout would shut the system down. When the above message appears, discharge pressure has exceeded the programmable threshold and the compressor is being unloaded in an effort to prevent shutdown on the high pressure cutout. The operation of this safety is important if condenser coils become dirty, if there is a problem with the condenser fan operation, or if extreme ambient or load conditions occur. See Anticipatory Unloading Controls Page 161 for detailed operation.

138 YORK INTERNATIONAL