Carrier Touch Pilot Junior, Manual, Page: 8 / 36

8
4.7 - Actuators
Electronic expansion valve
The electronic expansion valve (EXV) is used to adjust the
refrigerant flow to changes in the operating conditions of
the machine. The high degree of accuracy with which the
piston is positioned provides precise control of the
refrigerant flow and suction superheat.
Water flow switch
For units without internal pumps, the water flow switch
configuration allows for the automatic control of the
minimum water flow setpoint of the water flow switch. The
configuration depends on the unit size and is made
automatically at the start-up. If the flow switch fails, the
alarm condition shuts off the unit.
Water heat exchanger pumps (optional)
The controller can regulate one or two fixed speed or
variable speed water heat exchanger pumps and takes care
of the automatic changeover between these pumps (see
also section 8
.5).
Four-way valve (heat pumps only)
The control actuates the four-way valve for cooling /
heating mode and defrosts sessions.
4.8 - Terminal block connections
Connections available at the user terminal block may vary
depending on the selected options.
The following table summarizes the connections at the
user terminal block.
IMPORTANT: Some contacts can be accessed only when
the unit operates in Remote mode
.
4.8.1 - Volt-free contact (on/off and cooling/heating)
For chillers with a boiler or heat pumps, on/off contacts
and cooling/heating contacts are as follows:
Off
Cooling Heating Auto
On/Off contact
[ON_OFF_SW]
open closed closed open
Cooling/heating contact
[HC_SW]
open open closed closed
Off:
Unit is stopped
Cooling:
Unit is allowed to start in Cooling
Heating:
Unit is allowed to start in Heating (chiller with boiler control or heat
pump)
Auto:
Unit can run in Cooling or Heating in accordance with the changeover
values. If the auto changeover is enabled ( Heat/Cool Select
[HC_SEL]
, GENUNIT), the operating mode is selected based on OAT.
4.8.2 - Volt-free setpoint selection contact
This dry contact input is used to switch between setpoints.
It is active only when the control is in Remote mode.
Cooling Heating
Stp 1 Stp 2 Stp 1 Stp 2
Setpoint selection contact
[SP_SW]
open closed open closed
4.8.3 - Volt-free demand limit selection contact
Three steps demand limit based on two dry contacts can be
used to limit unit capacity.
100% Limit 1 Limit 2 Limit 3
Demand limit switch 1
[LIM_SW1]
open closed open closed
Demand limit switch 2
[LIM_SW2]
open open closed closed
Description Board Connector / Input / Output Terminal Remarks
On/Off Switch
SIOB #1 J1 / DI-01 32-33
Used for the unit on/off control (Remote mode)
Second Setpoint Switch SIOB #1 J1 / DI-02 65-66 Used to switch between setpoints See section 4.8.2
Limit Switch #1 SIOB #1 J1 / DI-03 73-74 Used to control demand limit. See section 4.8.3
Limit Switch #2 SIOB #1 J1 / DI-04 75-76 Used to control demand limit. See section 4.8.3
Heat/Cool Select SIOB #1 J3 / DI-06 63-64 Used to switch between cooling and heating when the unit is in
Remote mode (Heat pumps only)
Desuperheater Switch SIOB #1 J3 / DI-07 49-49A Heat recovery is allowed
power_input_stable SIOB #1 J3 / DI-08 -
Water Pump #1 SIOB #1 J6 / IN03-DO-03 - The control can regulate one or two evaporator pumps and
automatically change over between the two pumps
Water Pump #2 SIOB #1 J6 / IN04-DO-04 - The control can regulate one or two evaporator pumps and
automatically change over between the two pumps
Running Relay SIOB #1 J23 / DO-05 37-38 Indicates if the unit is ready to start or operating
Alarm Relay SIOB #1 J22 / DO-06 30-31 Indicates alarms
Limit Analog Signal SIOB #1 J9 / AI-10 43-44 Used for Setpoint Reset
Electrical Heat Stage #1 SIOB #2 J6 / DO-03 - Used to manage electric heating stage (1)
Electrical Heat Stage #2 SIOB #2 J6 / DO-04 - Used to manage electric heating stage (2)
Electrical Heat Stage #3 SIOB #2 J23 / DO-05 - Used to manage electric heating stage (3)
Boiler or Electrical Heat Stage #4 SIOB #2 J22 / DO-06 - Used to manage boiler heating or electric heating stage (4)