Bryant 580J*04--12 Manual de instalación descargar pdf (Pagina 10)

Relative Humidity Sensors (Space or Duct

Mounted)

The accessory space humidity sensor or duct humidity

sensor is used to measure the relative humidity of the air

within the space or return air duct. The RH reading is used

to control the Perfect Humidity

option of the rooftop unit.

For wiring distances up to 500 ft (152m), use a 3-conductor,

18 or 20 AWG shielded cable. The shield must be removed

from the sensor end of the cable and grounded at the unit

end. The current loop power for the sensor is provided by

the RTU Open controller as 24vdc. Refer to the instructions

supplied with the RH sensor for electrical requirements and

terminal locations. RTU Open configurations must be

changed after adding a RH sensor. See below and Figs. 10 &

11 for typical non--communicating RH sensor wiring.

S J4--1 or J4--4 = 24vdc loop power

S J4--2 or J4--5 = 4--20mA signal input

NOTE: The factory default for dehumidification control

is a normally open humidistat.

Installing Discrete Inputs

Compressor Safety

The compressor safety input provides the RTU Open with

feedback to when the compressor is not running and

should be. This feedback can be provided by a

Compressor Lock-Out (CLO) device or current switch

when field installed. Compressor safety is a dedicated

input on the configurable input 3 and tells the RTU Open

when the compressor is locked out. The normal condition

for compressor safety is good operation. A normally open

compressor safety is the factory default for all units.

Follow specific accessory instructions if installing a CLO

device. The CLO should wire into the unit’s Central

Terminal Board (CTB).

NOTE: Input 3 can also be wired into J--5.

SW2

12345 6

Vin

Gnd

MOUNTING

HOLES

WIRING

OPENING

a33-9141

Vin - J4 -1 or J4 -4 24Vdc

Io - J4 -2 or J4 -5 4 -20mA output

C07201

Fig. 10 -- Space Relative Humidity Sensor Typical Wiring

Humidistat

The accessory humidistat provides the RTU Open insight

to the relative humidity in the space. The humidistat reads

the RH level in the space and compares it to its setpoint to

operate a dry contact. The humidistat is a dedicated input

on the configurable input 9 and tells the RTU Open when

the RH level is HIGH or LOW. The normal condition for

humidity is LOW. A normally open humidistat is the

factory default control for the Perfect Humidity option. To

wire in the field:

S J5--8 = 24 VAC source for dry contact

S J5--7 = Signal input

Single Enthalpy (Outdoor Enthalpy)

The outdoor enthalpy switch/receiver (33CSENTHSW)

senses temperature and humidity of the air surrounding

the device and calculates the enthalpy when used without

an enthalpy sensor. The relay is energized when enthalpy

is high (above 28 BTU/lb OR dry bulb temperature is

above 75_F) and de-energized when enthalpy is low

(below 27 BTU/lb AND dry bulb temperature is below

74.5_F). The enthalpy input is dedicated to input 8 and

tells the RTU Open when the outside air enthalpy is HIGH

or LOW. The normal condition for the enthalpy input is

HIGH. Enthalpy is configured on input 8 in the factory

when it is added as an option.

NOTE: The enthalpy calculation is done using an

average altitude of 1000 ft above sea level.

For field installation, refer to the enthalpy accessory

instructions. For wiring see below and Fig. 10. The RTU

Open board provides 24vac on one of the two loose grey

wires in the return air section of the rooftop near the

12-pin economizer plug. To determine the correct grey,

measure the voltage on the wires with power applied to

the unit. If 24-vac is sensed, then that is the grey wire that

is connected to the RTU Open board at J2-7. The other is

the signal for input 8, connect it to the LOW Enthalpy

terminal on the enthalpy switch/receiver. Tie into the

12-pin economizer plug on pin 4 or the black wire

connected to the actuator for the enthalpy’s GND

connection. Power can also be provided direct from the

unit transformer and J5 terminal on the RTU Open.

S J2--7orJ5--2=24VACforenthalpyswitchpower

S J2--6 or J5--1 = input signal

Differential Enthalpy

Differential enthalpy control requires both an enthalpy

switch/receiver (33CSENTHSW) and an enthalpy sensor

(33CSENTSEN). The enthalpy sensor must be installed in

the field as the factory can only provide single enthalpy.

The enthalpy sensor must be mounted in the return

airstream and calculates the enthalpy of the indoor air.

The relay is energized when the enthalpy detected by the

return air enthalpy sensor is less than the enthalpy at the

enthalpy switch/receiver. The relay is de-energized when

the enthalpy detected by the return air enthalpy sensor is

greater than the enthalpy at the enthalpy switch/receiver

(differential enthalpy control).

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