Daikin MPS - Page 32

RPS-Two Small Comps on Circuit # 2, One
Large Comp on Circuit # 1, Four Stages (3/4/2-
410A, RTU)
With this conguration there are two standard and two
alternate xed sequences used when both circuits are enabled.
If both circuits are enabled and modulating hot gas reheat
dehumidication is not active, the staging sequence is Std-1
if compressor # 2 has fewer hours than compressor # 4, and
the staging sequence is Std-2 if compressor # 2 does not have
fewer hours than compressor # 4. If both circuits are enabled
and modulating hot gas reheat dehumidication is active, the
staging sequence is Alt-1 if compressor # 2 has fewer hours
than compressor # 4, and the staging sequence is Alt-2 if
compressor # 2 does not have fewer hours than compressor
# 4. Stage 3 is skipped in these sequences. If Circuit #2 is
disabled, compressor # 1 is staged on and off to maintain the
temperature setpoint.
If Circuit #1 is disabled the staging sequence is set to Std-1
if comp #2 has fewer hours than comp #4 and the staging
sequence is set to Std-2 if comp #2 does not have fewer hours
than comp #4.
If a circuit is disabled and then becomes re-enabled, no
change occurs until a new stage up or down request occurs.
At this time the staging is re-aligned to the “normal” condition
for the new stage.
NOTE: During this re-alignment, the cooling stage time
guaranteed on and off times must be observed as
well as a minimum of 10 seconds between starting
more than one compressor.
When both circuits are enabled the staging sequence is
changed only when the number of stages is zero or Maximum
Cooling stages.
Table 17: RPS Standard Staging
Compressor Staging
Staging
Sequence
Stage 1
Compressor
Stage 2
Compressors
Stage 3
Compressors
Stage 4
Compressors
Std-1 2 2, 4 1, 2 1, 2, 4
Std-2 4 2, 4 4,1 1, 2, 4
Alt-1 2 2, 4 NA 1, 2, 4
Alt-2 4 2, 4 NA 1, 2, 4
StgdClgCap 25% 50% 75% 100%
SCU-One Small Comp on Circuit #1, One Large
Comp on Circuit #2, on Large or Small Comp or
Circuit #3, Four Stages (3/3/4-410A, SCU)
With this conguration there are two possible xed sequences
used when all three circuits are enabled.
If all three circuits are enabled and compressor # 3 run hours
are greater than compressor # 1 run hours, the staging
sequence is Std-1. If all three circuits are enabled and
compressor # 1 run hours are greater than compressor # 3 run
hours, the staging sequence is Std-2. If Circuit # 1 is disabled,
compressor # 2 and # 3 are staged on and off to maintain the
temperature setpoint. Maximum cooling stages is set to 3. If
Circuit # 2 is disabled, compressor # 1 and # 3 are staged on
and off to maintain the temperature setpoint. Maximum cooling
stages is set to 2. If Circuit # 3 is disabled, compressor # 1 and
# 2 are staged on and off to maintain the temperature setpoint.
Maximum cooling stages is set to 3.
If a circuit is disabled and then becomes re-enabled, no
change occurs until a new stage up or down is requested. At
this time the staging is re-aligned to the “normal” condition for
the new stage.
— NOTE: During this re-alignment, the cooling stage
time guaranteed ON and OFF times must be
observed as well as a minimum of 10 seconds
between starting more than one compressor
If a circuit is disabled, its compressors do not run and are not
considered in runhour comparisons
Table 18: SCU Standard Staging
Compressor Staging
Staging
Sequence
Stage 1
Compressor
Stage 2
Compressors
Stage 3
Compressors
Stage 4
Compressors
Std-1 1 2 1, 2 1, 2, 3
Std-2 1 2 3, 2 1, 2, 3
StgdClgCap 25% 50% 75% 100%
IM 919-3 • MICROTECH III CONTROLLER 32 www.DaikinApplied.com
CoolIng: MulTIsTage