York Millennium YCAJ150, Installation Operation & Maintenance, Page: 60 / 116

60 YORK INTERNATIONAL
the rate of drop in water temperature exceeds 2X the
programmed Rate Sensitivity, no further loading or un-
loading will result since the micro sees the temperature
dropping at an excessive rate anticipating temperature
will soon fall into the CONTROL RANGE.
The micro is capable of providing 5, 7, or 10 steps of
loading/unloading. The chiller MUST be programmed for
the number of steps which were ordered. Otherwise,
improper operation and water temperature control prob-
lems will result.
NOTE. The micro controls loading and unloading re-
sponses on a 10 step scale regardless of the
number of stages present. Therefore, loading
and unloading responses on 5 & 7 step chillers
may appear delayed (time between steps in-
creased) when missing steps are activated or
de-activated by the micro, 5 STEP CONTROL
IS STANDARD.
Fig. 20 shows the loading and unloading sequences for
5, 7 and 10 steps of control.
FIG. 20 – LEAVING WATER CONTROL LOADING/UNLOADING
5 STEP (STANDARD)
TEMPERATURE
RISE LOAD UNLOAD
5 LEAD COMP + 1 STEP, LAG COMP + 1 STEP – – – – – – – – – – – – – – – – – – – – –
4 LEAD COMP + 1 STEP, LAG COMP UNLOADED – – – LEAD COMP + 1 STEP, LAG COMP UNLOADED
3 LEAD COMP UNLOADED, LAG COMP UNLOADED – – – LEAD COMP UNLOADED, LAG COMP UNLOADED
2 LEAD COMP + 1 STEP, LAG COMP OFF – – – LEAD COMP + 1 STEP, LAG COMP OFF
1 LEAD COMP UNLOADED, LAG COMP OFF – – – LEAD COMP UNLOADED, LAG COMP OFF
LEAD COMP OFF, LAG COMP OFF – – – LEAD COMP OFF, LAG COMP OFF
TEMPERATURE
FALL
7 STEP (OPTIONAL)
TEMPERATURE
RISE LOAD UNLOAD
7 LEAD COMP + 2 STEPS, LAG COMP + 2 STEPS – – – – – – – – – – – – – – – – – – – – –
6 LEAD COMP + 2 STEPS, LAG COMP + 1 STEP – – – LEAD COMP + 2 STEPS, LAG COMP + 1 STEP
5 LEAD COMP + 1 STEP, LAG COMP + 1 STEP – – – LEAD COMP + 1 STEP, LAG COMP + 1 STEP
4 LEAD COMP + 1 STEP, LAG COMP UNLOADED – – – LEAD COMP + 1 STEP, LAG COMP UNLOADED
3 LEAD COMP + 2 STEPS, LAG COMP OFF – – – – – – – – – – – – – – – – – – – – – *
2 LEAD COMP + 1 STEP, LAG COMP OFF – – – LEAD COMP + 1 STEP, LAG COMP OFF
1 LEAD COMP UNLOADED, LAG COMP OFF – – – LEAD COMP UNLOADED, LAG COMP OFF
LEAD COMP OFF, LAG COMP OFF – – – LEAD COMP OFF, LAG COMP OFF
TEMPERATURE
FALL
10 STEP (OPTIONAL)
TEMPERATURE
RISE LOAD UNLOAD
10 LEAD COMP + 3 STEPS, LAG COMP + 3 STEPS – – – – – – – – – – – – – – – – – – – – –
9 LEAD COMP + 3 STEPS, LAG COMP + 2 STEPS – – – LEAD COMP + 3 STEPS, LAG COMP + 2 STEPS
8 LEAD COMP + 2 STEPS, LAG COMP + 2 STEPS – – – LEAD COMP + 2 STEPS, LAG COMP + 2 STEPS
7 LEAD COMP + 2 STEPS, LAG COMP + 1 STEP – – – LEAD COMP + 2 STEPS, LAG COMP + 1 STEP
6 LEAD COMP + 1 STEP, LAG COMP + 1 STEP – – – LEAD COMP + 1 STEP, LAG COMP + 1 STEP
5 LEAD COMP + 1 STEP, LAG COMP UNLOADED – – – LEAD COMP + 1 STEP, LAG COMP UNLOADED
4 LEAD COMP + 3 STEPS, LAG COMP OFF – – – – – – – – – – – – – – – – – – – – – *
3 LEAD COMP + 2 STEPS, LAG COMP OFF – – – LEAD COMP + 2 STEPS, LAG COMP OFF
2 LEAD COMP + 1 STEP, LAG COMP OFF – – – LEAD COMP + 1 STEP, LAG COMP OFF
1 LEAD COMP UNLOADED, LAG COMP OFF – – – LEAD COMP UNLOADED, LAG COMP OFF
LEAD COMP OFF, LAG COMP OFF – – – LEAD COMP OFF, LAG COMP OFF
TEMPERATURE
FALL
* This step is skippped on a temperature drop.