Supplementary Heating; Pumps Control - Carrier SmartVu control Manual

6 - STANDARD CONTROL OPERATIONS AND OPTIONS

6.4 - 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.
6.4.1 - 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.
2. Select Heat/Cool Config (HCCONFIG).
3. Set Boiler OAT Threshold [boil_th].
Boiler OAT Threshold [boil_th]
-15.0 to 15.0°C
5.0 to 59.0°F
6.4.2 - 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.
2. Select Heat/Cool Config (HCCONFIG).
3. Set Elec Stage OAT Threshold [ehs_th].
Elec Stage OAT Threshold [ehs_th]
-5.0 to 21.0°C
23.0 to 70.0°F
IMPORTANT: Electric heating is not allowed when the demand
limit is active on the unit.
36
-9.9°C
14.2°F
5.0°C
41.0°F

6.5 - Pumps 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).
6.5.1 - Variable speed pumps control
30RBS chillers and 30RQS heat pumps may be fitted with one or
two variable speed pumps.
Variable speed pumps give the possibility of saving the pumping
energy cost, providing precise water flow control and improving
the overall performance of the system. The frequency inverter
continuously regulates the flow rate to minimise the pump power
consumption at full load and part load.
Water flow management methods are as follows:
■ Fixed speed control (the control ensures a constant pump speed
based on compressor capacity).
■ Water flow control based on constant water delta pressure (the
control continuously acts on the pump speed to ensure
a constant delta pressure).
■ Water flow control based on constant delta T on the water
exchanger.
Fixed speed pumps can be either low or high pressure, whereas
variable speed pumps are always high pressure pumps.
6.5.2 - Pumps configuration
The control can command internal fixed speed or variable speed
pumps as well as customer pumps (fixed speed or variable speed).
Variable speed pumps may also be configured as fixed speed
pumps (see also section 6.5.1).
IMPORTANT: Pump speed configuration can be performed
only by service technicians.
Basic pump configuration can be performed via the Configuration
menu (PUMPCONF – Pump Configuration). Only logged-in users
can access the menu. The unit must be stopped.
To set pumps sequence
1. Navigate to the Configuration menu.
2. Select Pump Configuration (PUMPCONF).
3. Set Cooler Pumps Sequence [pump_seq].
Cooler Pumps Sequence [pump_seq]
0 No Pump
1 One Pump Only
2 Two Pumps Auto
3 Pump#1 Manual
4 Pump#2 Manual