18
The lead machine will always be started first. When the
lead machine is at its full available capacity, start-up delay
(configurable) is initialised on the follower. When this delay
has expired, and if the error on the control point is greater
than 1.7°C, the follower unit is authorised to start and the
pump is activated. The follower will automatically use the
master unit active setpoint. The lead machine will be held at
its full available capacity for as long as the active capacity
on the follower is not zero. When the follower unit receives
a command to stop, its evaporator water pump is turned
off with 20 seconds delay.
In the event of a communication fault between the two
units, each shall return to an autonomous operating mode
until the fault is cleared. If the master unit is halted due to
an alarm, the slave unit is authorised to start without prior
conditions.
ATTENTION: For heat pumps operating in master/slave
mode and using an NRCP2 board or equipped with electric
heater stages control must be on the entering water
temperature.
6 - DIAGNOSTICS - TROUBLESHOOTING
6.1 - General
The Pro- control system has many fault tracing aid
functions. The local interface and its various menus give
access to all unit operating conditions. If an operating fault
is detected, an alarm is activated and an alarm code is
stored in the Alarms menu, sub-menus CUR_ALRM and
ALARMRST.
6.2 - Displaying alarms
The alarm LED on the interface (see chapter 4.1) allows
the quick display of the unit status.
•
A flashing LED shows that the circuit is operating but
there is an alert.
•
A steady LED shows that the circuit has been shut
down due to a fault.
The ALARMRST menu on the main interface displays up
to five fault codes that are active on the unit.
6.3 - Resetting alarms
When the cause of the alarm has been corrected the alarm
can be reset, depending on the type, either automatically
on return to normal, or manually when action has been
taken on the unit. Alarms can be reset even if the unit is
running.
This means that an alarm can be reset without stopping the
machine. In the event of a power supply interrupt, the unit
restarts automatically without the need for an external
command. However, any faults active when the supply is
interrupted are saved and may in certain cases prevent a
circuit or a unit from restarting.
A manual reset must be run from the main interface via
the ALARMRST menu, item RST_ALM. Depending on
the configuration in the GENCONF menu, access to the
item may be protected by a password.
