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)] x100%
= 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 00 000 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 00 000 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 N O.
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
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