McQuay MicroTech III RAH Operation And Maintenance Manual page 99

McQuay OM 920-1
Table 68: Alternate Staging
Staging Stage 1 Stage 2
Sequence Comps Comps
Std-1 1 1,3
Std-2 2 2,4
Std-3 3 1,3
Std-4 4 2,4
Std-5 5 5,7
Std-6 6 6,8
Std-7 7 5,7
Std-8 8 7,8
ClgCap 13% 25%
Eight Equal Sized Compressors, Eight Circuits, No WRV
Only one sequence is provided so the user makes no selections.
• Total cooling stages = 8.
• Maximum cooling stages is always set to 8.
• The Staging sequence is the Standard sequence that contains the enabled Stage 1
Compressor with the fewest run hours. Compressors in disabled circuits are ignored when
only enabled compressor run hours are compared.
• The Compressor Sequence changes only when the compressor stage is Maximum cooling
stages or zero. This means that disabling and re-enabling the compressors or turning the unit
off and on may be necessary to cause sequence changes.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on the disabled circuit stays off if it is already off and is turned off if it is
on.
Table 69: Standard Staging
Staging Stage 1 Stage 2
Sequence Comps Comps
Std-1 1 1,2
Std-2 2 1,2
Std-3 3 3,4
Std-4 4 3,4
Std-5 5 5,6
Std-6 6 5,6
Std-7 7 7,8
Std-8 8 7,8
ClgCap 13% 25%
Standard Staging
Stage 3 Stage 4 Stage 5
Comps Comps Comps
1,3,5 1,3,5,7 1,2,3,5,7
2,4,6 2,4,6,8 1,2,4,6,8
1,3,7 1,3,5,7 1,3,4,5,7
2,4,8 2,4,6,8 2,3,4,6,8
1,5,7 1,3,5,7 1,3,5,6,7
2,6,8 2,4,6,8 2,4,5,6,8
3,5,7 1,3,5,7 1,3,5,7,8
4,6,8 2,4,6,8 2,4,6,7,8
38% 50% 63%
Standard Staging
Stage 3 Stage 4 Stage 5
Comps Comps Comps
1,2,3 1,2,3,4 1,2,3,4,5
1,2,8 1,2,7,8 1,2,3,7,8
2,3,4 1,2,3,4 1,2,3,4,8
3,4,5 3,4,5,6 2,3,4,5,6
4,5,6 3,4,5,6 3,4,5,6,7
5,6,7 5,6,7,8 1,5,6,7,8
1,7,8 1,2,7,8 1,2,6,7,8
6,7,8 5,6,7,8 4,5,6,7,8
38% 50% 63%
Operator's Guide
Stage 6 Stage 7 Stage 8 Comps
Comps Comps
1,2,3,5,6,7 1,2,3,4,5,6,7 1,2,3,4,5,6,7,8
1,2,3,4,6,8 1,2,3,4,5,6,8 1,2,3,4,5,6,7,8
1,3,4,5,7,8 1,2,3,4,5,7,8 1,2,3,4,5,6,7,8
1,2,3,4,6,8 1,2,3,4,6,7,8 1,2,3,4,5,6,7,8
1,2,3,5,6,7 1,2,3,5,6,7,8 1,2,3,4,5,6,7,8
2,4,5,6,7,8 1,2,4,5,6,7,8 1,2,3,4,5,6,7,8
1,3,4,5,7,8 1,3,4,5,6,7,8 1,2,3,4,5,6,7,8
2,4,5,6,7,8 2,3,4,5,6,7,8 1,2,3,4,5,6,7,8
75% 88%
Stage 6 Stage 7 Stage 8 Comps
Comps Comps
1,2,3,4,5,6 1,2,3,4,5,6,7 1,2,3,4,5,6,7,8
1,2,3,4,7,8 1,2,3,4,5,7,8 1,2,3,4,5,6,7,8
1,2,3,4,7,8 1,2,3,4,6,7,8 1,2,3,4,5,6,7,8
1,2,3,4,5,6 1,2,3,4,5,6,8 1,2,3,4,5,6,7,8
3,4,5,6,7,8 1,3,4,5,6,7,8 1,2,3,4,5,6,7,8
1,2,5,6,7,8 1,2,3,5,6,7,8 1,2,3,4,5,6,7,8
1,2,5,6,7,8 1,2,4,5,6,7,8 1,2,3,4,5,6,7,8
3,4,5,6,7,8 2,3,4,5,6,7,8 1,2,3,4,5,6,7,8
75% 88%
100%
100%
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