Controls, Start-Up, Operation, Service and ... - Climayoreo

the motor position to be configured at initial unit start-up. The
motor(s) is located on the economizer and can be reached
through the filter access door.
THERMISTORS AND PRESSURE TRANSDUCERS —
The unit is equipped with several thermistors for measurement
of temperatures. The thermistors are summarized in Table 102.
The units have two pressure transducers that are connected
to the low side of the system. These two pressure transducers
measure the low side pressure and are used for low pressure
protection and coil freeze protection.
The units also have two pressure transducers that are connected
to the high side of the system. These two pressure transducers
measure the discharge pressure and are used to cycle the
condenser fans to maintain head pressure.
By using the high and low side pressure transducers, the
ComfortLink controls display the high and low side pressures
and saturation temperatures and a normal gage set is not
required.
SMOKE DETECTOR — The units can be equipped with an
accessory smoke detector located in the return air. The detector
is wired to the ComfortLink controls and, if activated, will stop
the unit by means of a special fire mode. The smoke detector
can also be wired to an external alarm system through TB201
terminals 1 and 2. The sensor is located in the return air section.
FILTER STATUS SWITCH — The units can be equipped
with an optional filter status switch. The switch measures the
pressure drop across the filters and closes when an adjustable
pressure set point is exceeded. The sensor is located in the return
air section behind the filter access door.
FAN STATUS SWITCH — The units can be equipped with
an optional fan status switch that will monitor the pressure rise
across the indoor fans.
RETURN AIR CO 2 SENSOR — The unit can be equipped
with a return air IAQ CO 2 sensor that is used for the demand
control ventilation. The sensor is located in the return air section
and can be accessed from the filter access door.
+24 V
GND
DCOM
DI-1
DI-2
DI-3
Terminal X1
DI-4
DI-5
135
BOARD ADDRESSES — Each board in the system has an
address. The MBB has a default address of 1 but it does have
an instance jumper that should be set to 1 as shown in Fig. 29.
For the other boards in the system there is a 4-dip switch header
on each board that should be set as shown below.
BOARD SW1 SW2 SW3 SW4
RXB 0 0 0 0
EXB 1 0 0 0
SCB 0 0 0 0
CEM 0 0 0 0
0 = On; 1 = Off
Accessory Control Components — In addition to
the factory-installed options, the units can also be equipped
with several field-installed accessories that expand the control
features of the unit. The following hardware components can
be used as accessories.
ROOM THERMOSTATS — The ComfortLink controls
support a conventional electro-mechanical or electronic thermostat
that uses the Y1, Y2, W1, W2, and G signals. The
control also supports an additional input for an occupied/
unoccupied command that is available on some new thermostats.
The ComfortLink controls can be configured to run with
up to 6 stages of capacity. The room thermostat is connected to
TB201.
The ComfortLink controls also support the use of space
temperature sensors and can be used with the T55 and T56
sensors. The controls can also be used with CCN communicating
T58 room sensor. The T55 and T56 sensors are connected
to TB201 terminals 1, 2, and 3. The T58 sensor is connected to
the CCN connections on COMM board. Whenever a unit
equipped with heat is operated without a thermostat, the user
must install the red jumpers from R to W1, and W2 on TB201
for the heat function to work correctly.
SPACE CO 2 SENSORS — The ComfortLink controls also
support a CO 2 IAQ sensor that can be located in the space for
use in demand ventilation. The sensor must be a 4 to 20 mA
sensor and should be connected to TB201 terminals 7 and 8.
10 11 12 13 14 15 16 17 18 28 29 30 31 32
DI-6
Fig. 34 — VFD Wiring
SCR
B(+)
A(-)
AGND
SCR
LEN connection from ComfortLink