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STAGE
0
COMP
A1
OFF
A2
OFF
B1
OFF
B2
OFF
UNIT
030
0%
035
0%
040
0%
050
0%
060
0%
Table 45 — Staging Sequence with Hot Gas Bypass — 48/50A3,A5030-060
STAGE
0
COMP
A1
OFF
ON*
A2
OFF
OFF
B1
OFF
OFF
B2
OFF
OFF
UNIT
030
0%
10%
035
0%
7%
040
0%
14%
050
0%
16%
060
0%
18%
*With minimum load valve ON.
COOLING MODE DIAGNOSTIC HELP — To quickly de-
termine the current trip points for the cooling modes, the Run
Status sub-menu at the local display allows the user to view the
calculated start and stop points for both the cooling and heating
trip points. The following sub-menu can be found at the local
display under Run Status
TRIP. See Table 46.
The controlling temperature is "TEMP" and is in the middle
of the table for easy reference. The HVAC mode can also be
viewed at the bottom of the table.
Table 46 — Run Status Mode Trip Helper
ITEM
EXPANSION
TRIP
MODE TRIP HELPER
UN.C.S
Unoccup. Cool Mode Start
UN.C.E
Unoccup. Cool Mode End
OC.C.S
Occupied Cool Mode Start
OC.C.E
Occupied Cool Mode End
TEMP
Ctl.Temp RAT,SPT or Zone
OC.H.E
Occupied Heat Mode End
OC.H.S
Occupied Heat Mode Start
UN.H.E
Unoccup. Heat Mode End
UN.H.S
Unoccup. Heat Mode Start
HVAC
The current HVAC MODE
SUMZ COOLING ALGORITHM — The SumZ cooling algo-
rithm is an adaptive PID which is used by the control whenever
more than 2 stages of cooling are present (C.TYP = 1,2,3, and
5). This section will describe its operation and define its param-
eters. It is generally not necessary to modify parameters in this
section. The information is presented primarily for reference
and may be helpful for troubleshooting complex operational
problems.
The only configuration parameter for the SumZ algorithm is
located
at
the
local
COOL
Z.GN. See Table 36.
Capacity Threshold Adjust (Z.GN) — This configuration is
used on units using the "SumZ" algorithm for cooling capacity
Table 44 — Staging Sequence without Hot Gas Bypass —
48/50A3,A5030-060 and Multi-Stage 48/50A2,A4030-060
SEQUENCE 1
1
2
3
Compressor Status
ON
ON
ON
OFF
OFF
ON
OFF
ON
ON
OFF
OFF
OFF
Unit Capacity 48/50A
25%
50%
75%
20%
50%
80%
25%
50%
75%
25%
50%
75%
25%
50%
75%
SEQUENCE 1
1
2
3
Compressor Status
ON
ON
ON
OFF
OFF
ON
OFF
ON
ON
OFF
OFF
OFF
Unit Capacity 48/50A
25%
50%
75%
20%
50%
80%
25%
50%
75%
25%
50%
75%
25%
50%
75%
CCN
UNITS
POINT
dF
UCCLSTRT
dF
UCCL_END
dF
OCCLSTRT
dF
OCCL_END
dF
CTRLTEMP
dF
OCHT_END
dF
OCHTSTRT
dF
UCHT_END
dF
UCHTSTRT
String
display
under
Configuration
4
0
ON
OFF
ON
OFF
ON
OFF
ON
OFF
100%
0%
100%
0%
100%
0%
100%
0%
100%
0%
4
5
0
ON
OFF
ON
OFF
ON
OFF
ON
OFF
100%
0%
100%
0%
100%
0%
100%
0%
100%
0%
control (Configuration
affects the cycling rate of the cooling stages by raising or
lowering the threshold that capacity must overcome in order to
add or subtract a stage of cooling.
The cooling algorithm's run-time variables are located at
the local display under Run Status
Current Running Capacity (C.CAP) — This variable rep-
resents the amount of capacity in percent that is currently
running.
Current Cool Stage (CUR.S) — This variable represents the
cool stage currently running.
Requested Cool Stage (REQ.S) — This variable represents
the cool stage currently requested by the control.
Maximum Cool Stages (MAX.S) — This variable is the max-
imum number of cooling stages the control is configured for
and capable of controlling.
Active Demand Limit (DEM.L) — If demand limit is active,
this variable will represent the amount of capacity that the
control is currently limited to.
Capacity Load Factor (SMZ) — This factor builds up or
down over time (–100 to +100) and is used as the means of
adding or subtracting a cooling stage during run time. It is a
normalized representation of the relationship between "Sum"
and "Z."
Next Stage EDT Decrease (ADD.R) — This variable rep-
resents (if adding a stage of cooling) how much the tempera-
ture should drop in degrees depending on the R.PCT calcula-
tion and exactly how much additional capacity is to be added.
ADD.R = R.PCT * (C.CAP — capacity after adding a cooling
stage)
For example: If R.PCT = 0.2 and the control would be
adding 20% cooling capacity by taking the next step up,
0.2 times 20 = 4 F (ADD.R).
40
SEQUENCE 2
1
2
3
Compressor Status
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
OFF
OFF
ON
Unit Capacity 48/50A
25%
50%
75%
20%
50%
70%
25%
50%
75%
25%
50%
75%
25%
50%
75%
SEQUENCE 2
1
2
3
Compressor Status
OFF
OFF
OFF
ON*
ON
ON
OFF
OFF
OFF
OFF
OFF
ON
Unit Capacity 48/50A
10%
25%
50%
7%
20%
50%
14%
25%
50%
16%
25%
50%
18%
25%
50%
UNIT
C.TYP = 1, 2, 3 and 5). It
COOL. See Table 47.
4
ON
ON
ON
ON
100%
100%
100%
100%
100%
4
5
OFF
ON
ON
ON
ON
ON
ON
ON
75%
100%
70%
100%
75%
100%
75%
100%
75%
100%
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