Cooling/Heating Selection; Supplementary Heating; Pump Control - Carrier Touch Pilot Junior Manual

8.3 - Cooling/heating selection

Cooling/Heating selection applies to chillers with the
boiler and heat pumps. Cooling/Heating selection can be
controlled in various ways, depending on the active
operating type. By default, the cooling mode is selected.
Cooling/Heating selection can be determined:
• Locally at the unit using the HC_SEL item in the
GENUNIT menu.
• Remotely via the heating/cooling selection contact, if
the unit is in the Remote mode.
• Via a network command if the unit is in the Network
mode.
Cooling/Heating mode can be set manually by the user or
automatically by the control. When cooling/heating is
automatic, the outdoor air temperature determines the
heat/cool/standby changeover (cauto_sp and hauto_sp,
SETPOINT). The automatic changeover is optional and
requires user configuration (HC_SEL, GENUNIT -
General Parameters).
To set cooling / heating / auto changeover
1. Navigate to the Main menu.
Select General Parameters (GENUNIT).
2.
3. Set Heat/Cool Select [HC_SEL].
Heat/Cool Select [HC_SEL]
0 Cooling
1 Heating
2 Automatic changeover
To set cool / heat changeover setpoint
1. Navigate to the Main menu.
Select Setpoint (SETPOINT).
2.
3. Set Cool Changeover Setpt [cauto_sp] or
Heat Changeover Setpt [hauto_sp].
Cool Changeover Setpt [cauto_sp]
3.9 to 50.0°C 23.9°C
39.0 to 122.0°F 75.0°F
Heat Changeover Setpt [hauto_sp]
0 to 46.1°C 17.8°C
32.0 to 115.0°F 64.0°F

8.4 - Supplementary heating

30RBS units may be fitted with a boiler that allows the unit
to run in heating mode if required. The boiler is active only
when the unit is in Heating mode.
30RQS heat pumps may be fitted with a boiler or electric
heaters. The boiler is used as heating replacement when
mechanical heating is not possible due to low outside air
temperature. Electric heaters can be turned on to satisfy
the heating demand when mechanical heating is
insufficient.
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8.4.1 - Boiler control
Boiler is activated when the outside air temperature is
below the user-configured boiler outdoor temperature
threshold which is by default set to -10°C (14°F).
To set boiler OAT threshold
1. Navigate to the Configuration menu.
Select Heat/Cool Config (HCCONFIG).
2.
3. Set Boiler OAT Threshold [boil_th].
Boiler OAT Threshold [boil_th]
-15.0 to 15.0°C -9.9°C
5.0 to 59.0°F 14.2°F
8.4.2 - Electric heating control
Electric heating stages can be activated as additional
heating when OAT is below the user-configured electric
heating OAT threshold which is by default set to 5°C
(41°F).
Electric heating is allowed when:
• Unit is running at 100% capacity.
• Electric pull-down time elapsed [ehs_pull].
• OAT is below the OAT threshold [ehs_th].
There are four electric heating stages, where the last
electric heating stage is used for back-up when the unit is
down due to a detected fault.
To set electric heating OAT threshold
1. Navigate to the Configuration menu.
Select Heat/Cool Config (HCCONFIG).
2.
3. Set Elec Stage OAT Threshold [ehs_th].
Elec Stage OAT Threshold [ehs_th]
-5.0 to 21.0°C 5.0°C
23.0 to 70.0°F 41.0°F
IMPORTANT: Electric heating is not allowed when the
demand limit is active on the unit.

8.5 - Pump control

The control system can manage one or two water
exchanger pumps, determining each pump on/off state and
its speed. Both pumps cannot run together. The pump is
turned on when this option is configured and when the unit
is running.
The pump is turned off when the unit is shut down due to
an alarm, unless the fault is a frost protection error. The
pump can be started in particular operating conditions
when the water exchanger heater is active.
If the pump has failed and another pump is available, the
unit is stopped and started again with the second pump. If
there is no pump available, the unit shuts down.
Configuration options may differ depending on the
number and type of pumps available (single speed pumps
or variable speed pumps).