Table of Contents
Advertisement
Cooling Control
The P Series ComfortLink controls offer two basic control ap-
proaches to mechanical cooling: multi-stage cooling (CV) and
multiple stages of cooling (VAV). In addition, the ComfortLink
controls offer the ability to run multiple stages of cooling for either
a space temperature sensor or thermostat by controlling the unit to
a low or high cool supply air set point. The control type (Configu-
ration
UNIT
C.TYP) determines the selection of the type of
cooling control as well as the technique for selecting a cooling
mode. Unit staging tables are shown in Appendix C.
NOTE: Whether a unit has a VFD or a supply fan installed for
static pressure control has no effect on configuration of machine
control type (C.TYP). No matter the control type, it is possible to
run the unit in either CV or VAV mode, provided there are enough
stages to accommodate lower air volumes for VAV operation. Re-
fer to Static Pressure Control section on page 72 for information
on how to set up unit for the type of supply fan control desired.
SETTING UP THE SYSTEM
Machine Control Type (Configuration
The most fundamental cooling control configuration is located un-
der Configuration
UNIT. See Table 33.
Table 33 — Machine Control Type
ITEM
EXPANSION
RANGE CCN POINT
UNIT
UNIT CONFIGURATION
C.TYP Machine Control Type
1 - 4
This configuration defines the technique and control source re-
sponsible for selecting a cooling mode and in determining the
method by which compressors are staged. The control types are:
•
C.TYP = 1 (VAV-RAT) and C.TYP = 2 (VAV-SPT)
Both of these configurations refer to standard VAV operation.
If the control is occupied, the supply fan is run continuously
and return-air temperature will be used for both in the deter-
mination of the selection of a cooling mode. VAV-SPT differs
from VAV-RAT only in that during the unoccupied period,
space temperature will be used instead of return-air tempera-
ture to start the fan for ten minutes before the return-air tem-
perature is allowed to call out any mode.
•
C.TYP
=
3
This configuration will force the control to monitor the
thermostat inputs to make a determination of mode. Unlike
a traditional 2-stage thermostat control, the unit is allowed
ITEM
OHSP
Occupied Heat Setpoint
OCSP
Occupied Cool Setpoint
UHSP
Unoccupied Heat Setpoint
UCSP
Unoccupied Cool Setpoint
GAP
Heat-Cool Setpoint Gap
V.C.ON
VAV Occ. Cool On Delta
V.C.OF
VAV Occ. Cool Off Delta
SASP
Supply Air Setpoint
SA.HI
Supply Air Setpoint Hi
SA.LO
Supply Air Setpoint Lo
SA.HT
Heating Supply Air Setpt
T.PRG
Tempering Purge SASP
T.CL
Tempering in Cool SASP
T.V.OC
Tempering Vent Occ SASP
T.V.UN
Tempering Vent Unocc. SASP
ITEM
EDT.R
EVAP.DISCHRGE TEMP RESET
RS.CF
EDT Reset Configuration
RTIO
Reset Ratio
LIMT
Reset Limit
RES.S
EDT 4-20 ma Reset Input
UNIT
C.TYP)
DEFAULTS
CTRLTYPE Model number dependent
(TSTAT
–
MULTI)
Table 35 — Setpoints
EXPANSION
Table 36 — Supply Air Reset Configuration
EXPANSION
to use multiple stages of cooling control and perform VAV
style operation. The control will be able to call out a LOW
COOL or a HIGH COOL mode and maintain a low or high
cool supply air set point.
•
C.TYP
=
This configuration will force the control to monitor a space
temperature sensor to make a determination of mode. Un-
like a traditional 2-stage space temperature control, the
unit is allowed to use multiple stages of cooling control
and perform VAV style operation. The control will be able
to call out a LOW COOL or a HIGH COOL mode and
maintain a low or high cool supply air set point.
MACHINE DEPENDENT CONFIGURATIONS
Some configurations are linked to the physical unit and must not
be changed. The configurations are provided in case the field re-
placement of a board occurs and the settings are not preserved by
the download process of the new software. The following configu-
rations apply to all machine control types (C.TYP). These config-
urations are located at the local display under Configuration
UNIT. See Table 34.
Table 34 — Machine Dependent Configurations
ITEM
EXPANSION
UNIT
SIZE
Unit Size (30-100)
Unit Size (SIZE)
There are 10 unit sizes (tons) for the P Series control. Make sure
this configuration matches the size called out by the model num-
ber of the unit. This is important as the cooling stage tables are de-
termined directly based on the SIZE configuration.
50 Hertz Unit? (50.HZ)
This configuration is not used.
SET POINTS
The set points for both cooling and heating are located at the local
display under Setpoints. See Table 35.
SUPPLY AIR RESET CONFIGURATION
Supply air reset can be used to modify the current cooling supply
air set point. Supply air reset is applicable to control types, C.TYP
= 1, 2, 3, and 4. The configurations for reset can be found at the lo-
cal display under Configuration
RANGE
UNITS
40 to 99
dF
40 to 99
dF
40 to 99
dF
40 to 110
dF
2 to 10
deltaF
0 to 25
deltaF
1 to 25
deltaF
45 to 75
dF
45 to 75
dF
45 to 75
dF
90 to 145
dF
–20 to 80
dF
5 to 75
dF
–20 to 80
dF
–20 to 80
dF
RANGE
UNITS
0 to 3
0 to 10
0 to 20
deltaF
Enable/Disable
49
4
(SPT
–
RANGE
CCN POINT
DEFAULTS
UNIT CONFIGURATION
30 to 100
UNITSIZE
Dependent on unit
EDT.R. See Table 36.
CCN POINT
DEFAULT
OHSP
OCSP
UHSP
UCSP
HCSP_GAP
VAVOCON
VAVOCOFF
SASP
SASP_HI
SASP_LO
SASPHEAT
TEMPPURG
TEMPCOOL
TEMPVOCC
TEMPVUNC
CCN POINT
DEFAULT
EDRSTCFG
RTIO
LIMT
EDTRSENS
Disable
MULTI)
68
75
55
90
5
3.5
2
55
55
60
85
50
5
65
50
2
3
10
Advertisement
Table of Contents
Troubleshooting
