Demand limit – Carrier PC 111 User Manual
Page 18
18
Demand Limit —
The demand limit function provides a
means to limit the cooling capacity of the VAV unit using an
external discrete switch function. When enabled by the closure
of the external switch, the control will limit the available com-
pressor staging capacity according to user set points established
at demand limit potentiometer(s).
The unit controls support two types of demand limit: single-
step and 2-step control.
SINGLE-STEP DEMAND LIMIT — This function will limit
the total compressor staging based on the ratio of the set point
potentiometer’s wiper arm position to the full scale resistance
of the potentiometer. The exact percentage of capacity reduc-
tion differs depending on the number of capacity steps.
A field-supplied potentiometer and control switch are re-
quired for this function. See installation section for specifica-
tion on potentiometer and field wiring.
TWO-STEP DEMAND LIMIT — Two-step demand limit is
provided with the installation of the accessory Demand Limit
Control Module kit plus installation of 2 field-supplied control
switches (SPST-NO each). This accessory control provides for
a first step reduction of 50% to 100% of the maximum com-
pressor staging; the second step provides for reduction
between 0% and 49%. The exact percentage of capacity reduc-
tion differs depending on the number of capacity steps.
When demand limit is active, the LED display will show
code 22 .
INSTALLATION
Single-Step Demand Limit — A 3-wire 5 to 20 K-ohm poten-
tiometer must be field-supplied and installed. A single-
pole normally open switch is also required (field-supplied
and -installed). Locate the potentiometer (designated P4) and
the switch in a suitable location (external from the unit or in the
unit control box).
SENSOR 1
SENSOR 2
SENSOR 3
SENSOR 4
RED
BLK
RED
BLK
RED
BLK
RED
BLK
TO ACCESSORY SPACE
TEMPERATURE RESET
CONTROL BOARD
RED
BLK
12
TB3
15
SIZES 034-048
12
TB4
15
SIZES 054-104
RED
BLK
RED
BLK
RED
BLK
SENSOR 1
SENSOR 2
SENSOR 3
RED
BLK
SENSOR 6
SENSOR 5
RED
BLK
SENSOR 4
RED
BLK
RED
BLK
RED
BLK
SENSOR 8
SENSOR 7
SENSOR 9
TO ACCESSORY SPACE
TEMPERATURE RESET
CONTROL BOARD
RED
BLK
12
15
TB3
SIZES 034-048
12
15
TB4
SIZES 054-104
SPACE TEMPERATURE RESET — 4 SENSOR AVERAGING APPLICATION
SPACE TEMPERATURE RESET — 9 SENSOR AVERAGING APPLICATION
Fig. 26 — Space Temperature Sensor Averaging
NOTE: Sensor part number is HH79NZ014.
- 42S
- 30GT
- 48SS060
- 50ME
- 38AH024-034
- ZC
- 30GA
- COMFORTLINK 48A2
- 48HE003---006
- 33ZCSECTRM
- 19XRV
- MODU-PAC 50DF
- 17DA
- SINGLE PACKAGED ELECTRIC COOLING UNITS 50GS
- 48JZ (N) 024-060
- 30GX080-176
- 50DL
- 50GL-A
- NP034-074
- 40GXQ
- 30XA080-500
- 39E
- 40KMQ------301
- 38AE
- 48AW
- 38GXQ
- 48ES---A
- 48GL
- 48GH
- 40QA024-060
- TJF004
- 39LD
- 48DL
- 48/50TC04---28
- 50EJ
- 17EX
- 50BA
- 50BB
- 50BB
- 50BJ
- 30H
- 48HJD005-007
- 50ZP
- 50DP016
- 50LJ008-014
- OMNIZONE 50XJ064-104
- 48SX024-048
- 38APS025-065
- 48TM028
- 38BA
- 50LJ
- 07D
- SYSTEM PILOT 33PILOT-01
- 50HG014-028
- 38AUZ
- 50SS018-060
- 50ZH024-060
- 38CKC036 Air
- 51FP
- ROOMTOP 50AH024-096
- WEATHERMAKER 48/50AJ
- 38AF
- 38AK024-044
- 5F
- 50DF034
- WEATHERMASTER 36TE
- 09DK054-084
- 50ZPA
- 48/50PD05
- 40QNC
- MOTORMASTER 48/50P2
- 51CV/GY
- 52F
- 52F
- 38GNA
- 38AKS013-024
- 48TC*D08
- 38AE016
- SEER 48ES
- 50TJ016-028
- MINIMUM LOAD CONTROL ACCESSORY 30XA080-500
- 48/50A020-060
- 48KLA
- 48KLA
- 50GS
- 40RU
- 40RU
- 50PG03-07
- Compressor and Condensing Unit
- PREMIERLINK 33CSPREMLK
- 48/50PG C03-14
- 38GS
- 48EL
- 48PM16---28
- 48VL-A
- 48XL
- 50CD/CH
- 48FK
- OMNIZONE 50XCA06-24
- 48KH
- 00EFN900003000A
- 48DH
- 48GS(N)-2SB
- T--298
- 38ED
- 38TXA
- 38SE
- Packaged Terminal s & Heat Pumps 52P
- WEATHERMAKER 48AJ
- 50AH
- 06D
- WEATHERMAKER ZONEKIT2ZCAR
- 51QC/QG
- 48TC**16
- 30HR
- 50HJ004
- 38CQ
- 38CQ
- 52C
- P
- 50TC
- MODULINE 37HS
- 50EE
- 50MH
- 30HH
- 38EB
- 38AKS
- 38TRA
- 38CKW
- 39L
- 38CKC
- 50DP
- 040-420
- 38HDR018-060
- 38AKS028-044
- 48VT(N)
- 38GP
- 48/50P030-100
- 51CM
- 52C
- 38AH044-084
- 06E
- 50SX
- 50VL---A
- LIGHT COMMERCIAL CONDENSING UNITS 38HDL018-060
- 50DP020
- 38EC
- 50XP
- 48HJ004-014
- 38JB
- REFRIGERANT R-410A
- 42 SERIES
- 42GW
- 48N
- 48SS018-060
- 48TJF008-012
- 48HDT
- 38TMA
- 38QH
- 40RMQ008-028
- 09BB
- 38GF
- T-326
- 30GX080-265
- MINIMUM LOAD CONTROL ACCESSORY 30RB060-390
- 38HDL018-060
- 49004DP109
- 324423-751
- WEATHERMASTER 48/50Z030-105
- 48TM016-028
- 38CKB
- 09DK054-094
- 48TF004-007
- 38EN
- 38HD
- 38CKC(Q)
- 09DC
- 38VH
- 39E/ER
- 48ES
- RTU OPEN 11-808-427-01
- 38AU
- 07E
- 38GK
- 5H
- 5H
- 19DG
- 50AH024-060
- 42VMC
- 42XQ_42XQA
- 50HJ015
- 19 Series
- 1995 Room Air
- 73Y