York YCAQ10, Руководство пользователя, Страница: 57 / 99

FORM 150.40-NM20
57
YORK INTERNATIONAL
(YCHA120, 150, 175 & 200)
OPTIONAL LOADING/UNLOADING
(LEAVING WATER TEMPERATURE (LWT)
CONTROL)
Optional loading and unloading of cylinders can be
accomplished in response to leaving chilled water tem-
perature as sensed by the Micro Logic Board.
It is advisable, to assure that cycling problems do not
occur, to use LWT Control only if 8 stages of loading
and unloading is present on the chiller. In addition, 8
stage control from the Micro Logic Board is initiated by
placing J8 IN or Sw. 5 ON. Note: J8 should only be IN
or Sw.5 ON if the chiller is equipped with 6 or 8 stages.
LWT Control is selected by placing J10 IN or Sw. 3 ON
on the Micro Logic Board. Various cooling ranges can
then be selected depending upon the allowable devia-
tion from setpoint.
Control Ranges can be selected on the front panel with
the Cooling Range Rotary Switch. The Cooling Range
Codes and their respective cooling ranges are listed
above right for optional LWT Control. Note: ON LWT
Control, the cooling ranges on the Control Panel are no
longer meaningful.
CAUTION: Selection of the Cooling Range should be
made according to the deviation from
setpoint which can be tolerated and whether
more than normal system cycling of the
loaders and compressors is experienced
due to a cooling range which is too tight.
Pages 57-59 show a listing of each cooling range code
along with the temperatures at which each stage loads
and unloads.
Code Range
0 + 1.0°F
1 + 1.2°F
2 + 1.4°F
3 + 1.5°F
4 + 1.6°F
5 + 1.8°F
6 + 1.9°F
7 + 2.0°F
LWT COOLING RANGES (6 AND 8 STAGE)
If the LWT option is utilized, loading and unloading for
each stage and the respective temperature at which it
occurs is shown in the tables on pages 57-59. A table is
provided for each of the Cooling Range Codes 0-7.
* If optional 6 stage loading/unloading is included, stage 4 loading and unloading is not included on either compressor. Therefore, in the
examples above, no system response will take place at the temperatures where stage 4 is to be activated or deactivated.
STAGE ON OFF
Lag Compr. Loader Stage 4* Setpoint plus 1.0°F Setpoint plus 0.4°F
COOLING RANGE Lag Compr. Loader Stage 3 Setpoint plus 0.8°F Setpoint plus 0.2°F
SWITCH = 0 Lag Compr. Loader Stage 2 Setpoint plus 0.6°F Setpoint
Lag Compressor Stage 1 Setpoint plus 0.4°F Setpoint minus 0.2°F
COOLING RANGE Lead Compr. Loader Stage 4* Setpoint plus 0.2°F Setpoint minus 0.4°F
OF +1°F Lead Compr. Loader Stage 3 Setpoint Setpoint minus 0.6°F
Lead Compr. Loader Stage 2 Setpoint minus 0.2°F Setpoint minus 0.8°F
Lead Compressor Stage 1 Setpoint minus 0.6°F Setpoint minus 1.0°F
STAGE ON OFF
Lag Compr. Loader Stage 4* Setpoint plus 1.2°F Setpoint plus 0.9°F
COOLING RANGE Lag Compr. Loader Stage 3 Setpoint plus 1.0°F Setpoint plus 0.7°F
SWITCH = 1 Lag Compr. Loader Stage 2 Setpoint plus 0.8°F Setpoint plus 0.5°F
Lag Compressor Stage 1 Setpoint plus 0.5°F Setpoint plus 0.2°F
COOLING RANGE Lead Compr. Loader Stage 4* Setpoint plus 0.3°F Setpoint
OF +1.2°F Lead Compr. Loader Stage 3 Setpoint Setpoint minus 0.4°F
Lead Compr. Loader Stage 2 Setpoint minus 0.3°F Setpoint minus 0.8°F
Lead Compressor Stage 1 Setpoint minus 0.6°F Setpoint minus 1.2°F