8
CAPACITY SEQUENCE DETERMINATION (
) —
This is configurable as equal circuit loading or staged circuit
loading with the default set at staged. The control determines
the order in which the steps of capacity for each circuit are
changed. This control choice does NOT have any impact on
machines with only 2 compressors.
MINIMUM LOAD VALVE (
) — When this option is
installed and configured, the first stage of capacity is altered by
energizing the Minimum Load valve relay. Once the control
requires more capacity, the minimum load valve is deenergized
and normal capacity staging resumes with loaders and com-
pressors. Similarly, the Minimum Load valve relay will be
energized for the last stage of capacity to be used before the
circuit is shut down.
Configure Unit for Minimum Load Control — The chiller
must be configured for minimum load control operation. This
may be done using the unit keypad (HSIO-2). Set the LOCAL/
OFF/REMOTE (LOR) switch in the OFF position.
1. Press
on the keypad.
2. Press the down arrow
until the display reads:
MIN. LOAD VALVE SELECT
DISABLE
3. To enable the minimum load valve feature, press
.
4. The display may read as follows. (If not, skip to Step 7.)
PASSWORD PROTECTED FUNCTION
ENTER PASSWORD
5. Press .
6. The HSIO-2 again displays the following:
MIN. LOAD VALVE SELECT
DISABLE
7. Press
. The display changes to:
MIN. LOAD VALVE SELECT
ENABLE
ENTER
ENTER
ENTER
L1
L2
L3
T1
T1
T3
3
2
1
1
2
3
4
6
5
COMPRESSOR JUNCTION BOX
JUMPER BARS
COMPRESSOR CONTACTOR
1
2
3
21
22
23
TERMINAL BLOCK
1
2
3
4
5
6
1
2
3
T1
T1
T1
T2
T2
T2
T3
T3
T3
S
2M
1M
L3
L3
L3
L2
L2
L2
L1
L1
L1
1
2
3
22
21
23
TERMINAL BLOCK
COMPRESSOR STARTER ASSEMBLY
COMPRESSOR JUNCTION BOX
21
22
23
4
6
5
Fig. 2 — Across-the Line (XL) Compressor Wiring
Fig. 3 — Wye-Delta Compressor Wiring
