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EDT Reset Configuration (RS.CF)
This configuration applies to several machine control types (Con-
figuration
UNIT
C.TYP = 1,2,3, and 4).
•
0
=
No supply air reset is in effect.
•
1
=
Space temperature will be used as the reset control variable
along with both RTIO and LIMT in the calculation of the fi-
nal amount of reset to be applied (Inputs
•
2
=
Return-air temperature will be used as the reset control
variable along with both RTIO and LIMT in the calcula-
tion of the final amount of reset to be applied (Inputs
RSET
SA.S.R).
•
3
=
THIRD
The reset value is determined by a 4 to 20 mA third-party
input. An input of 4 mA would correspond to 0ºF reset. An
input of 20 mA would correspond to 20ºF reset. Configur-
ing the control for this option will cause RES.S to become
enabled automatically with the CEM board. To avoid
alarms, make sure the CEM board and third-party input are
connected before enabling this option.
Reset Ratio (RTIO)
This configuration is used when RS.CF is set to 1 or 2. For every
degree that the controlling temperature (space/return) falls below
the occupied cooling set point (OCSP), the calculated value of the
supply air reset will rise by the number of degrees as specified by
this parameter.
Reset Limit (LIMT)
This configuration is used when RS.CF is set to 1 or 2. This con-
figuration places a clamp on the amount of supply air reset that
can be applied.
EDT 4-20 mA Reset Input (RES.S)
This configuration is automatically enabled when Configura-
tion
EDT.R
RS.CF is set to 3 (third-party reset).
COOLING CONFIGURATION
Relevant configurations for mechanical cooling are located at the
local display under Configuration
Enable Compressor A1 (A1.EN)
This configuration is used to disable the A1 compressor in case of
failure for size 30 to 100 units.
Enable Compressor A2 (A2.EN)
This configuration is used to disable the A2 compressor in case of
failure for size 50 to 100 units. It is always disabled for size 30 to
40 units.
Enable Compressor A3 (A3.EN)
This configuration is used to disable the A3 compressor in case of
failure for size 90 and 100 units. It is always disabled for size 30 to
75 units.
Enable Compressor B1 (B1.EN)
This configuration is used to disable the B1 compressor in case of
failure for size 30 to 100 units.
Enable Compressor B2 (B2.EN)
This configuration is used to disable the B2 compressor in case of
failure for size 40 to 100 units. It is always disabled for size 30 and
35 units.
Enable Compressor B3 (B3.EN)
This configuration is used to disable the B3 compressor in case of
failure for size 90 and 100 units. It is always disabled for size 30 to
75 units.
NO
RESET
SPT
RESET
RSET
SA.S.R).
RAT
RESET
PARTY
RESET
COOL. See Table 37.
CSB A1 Feedback Alarm (CS.A1)
This configuration is used to enable or disable the compressor A1
feedback alarm. This configuration must be enabled whenever
A1.EN is enabled.
CSB A2 Feedback Alarm (CS.A2)
This configuration is used to enable or disable the compressor A2
feedback alarm. This configuration must be enabled whenever
A2.EN is enabled.
CSB A3 Feedback Alarm (CS.A3)
This configuration is used to enable or disable the compressor A3
feedback alarm. This configuration must be enabled whenever
A3.EN is enabled.
CSB B1 Feedback Alarm (CS.B1)
This configuration is used to enable or disable the compressor B1
feedback alarm. This configuration must be enabled whenever
B1.EN is enabled.
CSB B2 Feedback Alarm (CS.B2)
This configuration is used to enable or disable the compressor B2
feedback alarm. This configuration must be enabled whenever
B2.EN is enabled.
CSB B3 Feedback Alarm (CS.B3)
This configuration is used to enable or disable the compressor B3
feedback alarm. This configuration must be enabled whenever
B3.EN is enabled.
Capacity Threshold Adjust (Z.GN)
This configuration provides an adjustment to the SUMZ Cooling
Algorithm for capacity control. The configuration affects the cy-
cling rate of the cooling stages by raising or lowering the threshold
that demand must build to in order to add or subtract a stage of
cooling. Normally this configuration should not require any tuning
or adjustment. If there is an application where the unit may be sig-
nificantly oversized and there are indications of high compressor
cycles, then the Capacity Threshold Adjust (Z.GN) can be used to
adjust the overall logic gain. Normally this is set to 1.0, but the
value can be adjusted from 0.1 to 10. As the value of Z.GN is in-
creased, the cycling of cooling stages will be slowed.
Compressor Lockout Temperature (MC.LO)
This configuration defines the outdoor air temperature below
which mechanical cooling is locked out.
Lead/Lag Operation? (LLAG)
This configuration selects the type of lead/lag compressor opera-
tion for the unit. There are 3 choices: automatic, circuit A, and cir-
cuit B.
0 = AUTOMATIC
If this configuration is set to "AUTOMATIC", every time
cooling capacity drops to 0%, on the next call for cooling, the
control will start up the first compressor on the circuit that did
not start on the previous cooling cycle.
1 = CIRCUIT A
If this configuration is set to "CIRCUIT A", every time cool-
ing capacity drops to 0%, a circuit A compressor is always
the first to start on the next call for cooling.
2 = CIRCUIT B
If this configuration is set to "CIRCUIT B", every time cool-
ing capacity drops to 0%, a circuit B compressor is always the
first to start on the next call for cooling.
NOTE: If the unit is configured for a Digital Scroll (Configura-
tion
COOL
DG.A1 = YES) or Minimum Load Valve (Config-
uration
COOL
MLV = ENABLE), then circuit A is always
the lead circuit regardless of the setting of this configuration.
50
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Troubleshooting
