York R123 Benutzerhandbuch

Seite von 156
FORM 160.55-O1 (604)
105
YORK INTERNATIONAL
in series to achieve a 900VDC capability for the DC 
link. It is important the voltage is shared equally from 
the junction of the center or series capacitor con nec tion, 
to the negative bus and to the positive bus. This center 
point should be approximately ½ of the total DC link 
voltage. 
HARMONIC FILTER – INPUT 
CURRENT OVERLOAD

The three phases of RMS Þ lter current are monitored 
and if any one of the three phases continuously ex ceeds 
a given threshold for 7 seconds, a chiller shutdown is 
performed and this message is displayed. The max i mum 
permissible continuous RMS current ratings for the har-
monic Þ lter are: 
                351/292 HP    =     128 AMPS
                503/419 HP    =     176 AMPS
                790/658 HP    =     277 AMPS 
HARMONIC FILTER – LOGIC BOARD
POWER SUPPLY

The low voltage power supplies on the Þ lter logic board 
have decreased below their permissible operating range. 
The Þ lter logic board receives its power from the VSD 
logic board via the ribbon cable, connecting the two 
boards. 
HARMONIC FILTER – RUN SIGNAL
When a digital run command is received at the Þ lter logic 
board from the VSD logic board via the 16 po si tion rib-
bon cable, a 1/10 second timer is started. If a redundant 
run command does not occur on the serial data link from 
the VSD logic board before the timer expires, a shut-
down is performed and this message is generated.  
HARMONIC FILTER – DC CURRENT 
TRANSFORMER 1

During initialization, with no current ß owing through the 
DC Current Transformers (DCCT’s), the DCCT out put 
voltages are measured and compared with a preset limit 
via the Þ lter logic board. If the measured values exceed 
the preset limits, the DCCT’s are presumed to be defec-
tive and this shutdown is generated. 
HARMONIC FILTER – DC CURRENT 
TRANSFORMER 2

See “Harmonic Filter – DC Current Transformer 1” 
message above. 
SAFETY SHUTDOWN MESSAGES
EVAPORATOR – LOW PRESSURE
(This message is applicable only if the Smart Freeze 
feature is not activated. If Smart Freeze is activated and 
has initiated the shutdown, “Evaporator – Low Pres sure 
– Smart Freeze” is displayed as described next.)
The evaporator pressure, as sensed by the Evaporator 
Transducer, has decreased to the Safety shutdown thresh-
 old. For water cooling applications, the safety shut down 
threshold is a Þ xed value for the respective re frig er ant. For 
Brine cooling applications, the safety shut down thresh old 
varies according to the con cen tra tion of the Brine solu-
tion. The Brine shutdown thresh old is pro grammed at the 
YORK Factory. It should not be changed by any one other 
than a qualiÞ ed Service Technician fol low ing instructions 
in YORK Service Manual 160.55-M1. The chiller can be 
started after the evaporator pres sure in creas es to the restart 
threshold and the COM PRES SOR switch is placed in the 
Stop-Reset  (O)  po si tion.
 
                                                      Shutdown (PSIA)              Restart (PSIA)
  Water cooling -     R11                            <5.4                                  >5.4 
                               R123                          <4.4                                  >4.4
  Brine cooling -      R11/R123              0.0 to 12.5                               >
                                                        as programmed            Shutdown threshold
 
 
 
“EVAPORATOR – LOW PRESSURE – SMART 
FREEZE”
Smart Freeze Protection is activated and has shut down 
the chiller because the evaporator tem per a ture has been 
below the Smart Freeze thresh old for greater than the al-
lowable num ber of seconds. If the evaporator re frig er ant 
tem per a ture sensor RT7 is Enabled (using pro ce dure in 
Service  Man u al  160.55-M1),  this  pa ram e ter  is  used  as 
the evaporator refrigerant tem per a ture and the freeze 
threshold is 32.8°F. If RT7 is not Enabled, the evaporator 
refrigerant temperature used is the Evap o ra tor  Satura-
tion Temperature, derived from the Evap o ra tor Pres sure 
Trans duc er and the freeze threshold is 34.0°F.
The count is incremented once for every second the 
evaporator refrigerant temperature is below the freeze 
threshold (but is never decremented below zero). The 
number of seconds it will take the chilled liquid to 
freeze is based on how far the evaporator refrigerant 
tem per a ture is below the freeze threshold as follows:
Number of seconds to freezing = (4053.7) / (freeze 
thresh old-evaporator refrigerant temperature)
Smart Freeze is activated only if the feature has been 
2