85
APPENDIX B
Capacity Loading Sequence Example —
The fol-
lowing tables show the loading sequence for a 30HX186
(50/50 split) and a 30HX161 (59/41 split) chiller. Each
compressor has 2 loaders. There is no difference in operation
between “Staged” and “Equal” circuit loading on 2 compressor
chillers.
LEGEND
NOTES:
1. Stage 3A (and 3B for 59/41 split) is not used by the algorithm
when increasing stages. Stage 3 (and 2 for a 59/41 split) is not
used when decreasing stages.
2. The % Total Capacities above are calculated based on compres-
sor nominal tons. For the case of the 59/41 split above, the 30HX
uses compressors with flow rates of 250 and 174 cfm (from com-
pressor model numbers 06N__
250
and 06N__
174
), which repre-
sent nominal tons of 80 and 56 (respectively) at 60 Hz. A factor of
40% is used when no loaders are energized, and a factor of 70%
is used when Loader 1 is energized. The capacity shown for
Stage 3B above is calculated as follows:
% Total Capacity = [(0.40 x 80 + 0.70 x 56)/(80 + 56)] x 100%
= 52.4 %
Nominal Tons
STANDARD LOADING SEQUENCE (CIRCUIT A LEAD CIRCUIT, 2-COMPRESSOR UNIT)
STAGE
COMP
A1
LOADER
A1
LOADER
A2
COMP
B1
LOADER
B1
LOADER
B2
% TOTAL
CAPACITY
(50/50 Split)
% TOTAL
CAPACITY
(59/41 Split)
0
0
0
0
0
0
0
0.0
0.0
1
1
0
0
0
0
0
20.0
23.5
2
1
1
0
0
0
0
35.0
41.1
3
1
1
1
0
0
0
50.0
58.8
4
1
1
0
1
1
0
70.0
70.0
5
1
1
0
1
1
1
85.0
82.4
6
1
1
1
1
1
1
100.0
100.0
CLOSE CONTROL LOADING SEQUENCE (CIRCUIT A LEAD CIRCUIT, 2-COMPRESSOR UNIT)
STAGE
COMP
A1
LOADER
A1
LOADER
A2
COMP
B1
LOADER
B1
LOADER
B2
% TOTAL
CAPACITY
(50/50 Split)
% TOTAL
CAPACITY
(59/41 Split)
0
0
0
0
0
0
0
0.0
0.0
1
1
0
0
0
0
0
20.0
23.5
2
1
1
0
0
0
0
35.0
41.1
3
1
1
1
0
0
0
50.0
58.8
3A
1
0
0
1
0
0
40.0
40.0
3B
1
0
0
1
1
0
55.0
52.4
4
1
0
0
1
1
1
70.0
64.7
5
1
1
0
1
1
1
85.0
82.4
6
1
1
1
1
1
1
100.0
100.0
0
— Off
1
— On
COMPRESSOR
PART NO.
60 Hz NOM.
TONS
50 Hz NOM.
TONS
06N__123
39
—
06N__146
46
39
06N__174
56
46
06N__209
66
56
06N__250
80
66
06N__300
—
80
