Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 163

Table 109 — Thermistors and Unit Operation Control Pressure Transducers
SENSOR
Thermistors
Cooling Coil Thermistor input. Provided with factory-option hydronic heat. Located on face of the hydronic
CCT
heating coil. Consists of 4 thermistors wired into a 2x2 array.
LST Limit Switch Thermistor. Provided with Staged Gas Control option. Located in the heating compartment.
OAT
Outside Air Thermistor. Located in the condenser section on the back side of the power box.
Return Air Thermistor.
RAT Without Economizer: Located on left side base rail in the return plenum.
With Economizer: Located on left side face of return damper section in the return plenum.
Supply Air Thermistor. Located in the Supply Fan section, on left side of the fan housing. (May be
SAT
relocated or replaced when unit is used with CCN Linkage systems; see page 71.)
Leaving Air Thermistors, provided with Staged Heat Control option. Shipped in the control box. Installer
LAT 1,2,3
must pull out and mount in the supply duct.
ST-A1 Suction Thermistor, Circuits A1 and A2. Located in well in evaporator outlet. A1 is top coil, A2 is bottom
ST-A2 coil
ST-B1 Suction Thermistor, Circuits B1 and B2. Located in well in evaporator outlet. B1 is top coil, B2 is bottom
ST-B2
coil
LT_A Liquid Line Thermistor, Circuit A. Located in evaporator section on inlet to EXV A1 and A2.
LT_B Liquid Line Thermistor, Circuit B. Located in evaporator section on inlet to EXV B1 and B2.
Control Pressure Transducers
BP Building Pressure. Provided with Power Exhaust and Return Fan options. Located in the control box.
DPT-A Discharge Pressure (refrigerant), Circuit A.
DPT-B
Discharge Pressure (refrigerant), Circuit B.
SPT-A Suction Pressure (refrigerant), Circuit A.
SPT-B Suction Pressure (refrigerant), Circuit B.
DP Duct Static Pressure. Provided with VAV models equipped with VFD options. Located in the control box. HK05ZG010
Supply Air Cfm (velocity pressure). Provided with factory-option return fan system
SACFM
(75-100 ton only). Located in the control box.
Return Air Cfm (velocity pressure). Provided with factory-option return fan system
RACFM
(75-100 ton only). Located in control box.
Outside Air Cfm Monitor (velocity pressure). Provided with the Outside Air Cfm Control option. Located in
OACFM
control box.
Digital Scroll Discharge Temperature Thermistor. Provided with digital scroll compressor option. Located
DTT
on discharge line.
RGTA Circuit A Return Gas Thermistor. Provided with MLV option. Located in suction line well.
FT_SF SACFM Supply Air CFM - Sensor bars are mounted on inlet to fan. Transducer is mounted in Control Box and is
fan dependent.
FT_PE EACFM Power Exhaust CFM - Sensor bars are mounted on inlet to fan. Transducer is mounted in Control Box
and is fan dependent.
FT_RF RACFM Return Air CFM - Sensor bars are mounted on inlet to fan. Transducer is mounted in Control Box and is
fan dependent.
Outside Air CFM - Sensor bars are mounted on air intake, same side as Control Box. Transducer is
OACFM
mounted in Control Box and is Unit size dependent.
MFDP Filter Pressure Sensor - Return (+24 VDC, 4 20 mA loop power). Transducer is mounted in Control Box. HK05ZG019
PFDP
Filter Pressure Sensor - Return (+24 VDC, 4 20 mA loop power). Transducer is mounted in Control Box. HK06WC035
LEGEND
CCN — Carrier Comfort Network
EXV —
Expansion Valve Control Board
MLV —
Minimum Load Hot Gas Bypass Valve
VAV — Variable Air Volume
VFD — Variable Frequency Drive
SPACE CO SENSORS
2
The ComfortLink controls also support a CO
can be located in the space for use in demand controlled venti-
lation. The sensor must be a 4 to 20 mA sensor and should be
connected to TB201 terminals 7 and 8.
ECONOMIZER HUMIDITY CHANGEOVER SENSORS
• The ComfortLink controls support 5 different changeover
systems for the economizer. These are:
• Outdoor enthalpy switch
• Outdoor air dry bulb
• Differential dry bulb
• Outdoor air enthalpy curves
• Differential enthalpy
• Custom curves (a combination of an enthalpy/dew point
curve and a dry bulb curve).
DESCRIPTION AND LOCATION
The units are equipped as standard with an outdoor air enthalpy
control. Outside air and return air dry bulb sensors, which sup-
IAQ sensor that
2
port the dry bulb changeover method, are also supplied as stan-
dard. If the other methods are to be used, then a field-installed
humidity sensor must be installed for outdoor air enthalpy and
customer curve control and 2 humidity sensors must be in-
stalled for differential enthalpy. Installation holes are pre-
drilled and wire harnesses are installed in every unit for con-
nection of the humidity sensors. The ComfortLink controls
have the capability to convert the measured humidity and dry
bulb temperature into enthalpy.
163
PART NO.
HH79NZ039 (4)
HH79NZ034
HH79NZ039
HH79NZ039
HH79NZ039
HH79NZ034 (3)
HH79NZ014 (2)
HH79NZ014 (2)
HH79EZ003
HH79EZ003
HK05ZG022
HK05ZZ001
HK05ZZ001
HK05SZ003
HK05SZ003
HK05ZG015
HK05ZG07
48NG501985 (75-105)
48NG501986 (120-150)
HH79EZ003
HH79NZ014
HK05ZG019 (Low Fan)
HK05ZG023 (High Fan)
HK05ZG019 (Low Fan)
HK05ZG023 (High Fan)
HK05ZG020 (Low Fan)
HK05ZG023 (High Fan)
48NG501985 (75 - 105)
48NG501986 (120 - 150)