Carrier AQUASNAP 30RH - Manual (Page 11)

30RA/30RH
GB - 10
Refrigerant charge and electronic control
Undercharge
If there is not enough refrigerant in the system, this is indicated by
gas bubbles in the moisture sight glass.
There are two possibilities:
• Small undercharge (bubbles in the sight glass, no significant
change in suction pressure).
- After detection and repair the unit can be recharged.
- The replenishment of the charge must always be done in the
cooling mode, slowly introducing liquid refrigerant at the suction
side, until there are no bubbles in the sight glass.
• Significant undercharge (large bubbles in the sight glass,
significant drop in suction pressure).
- Completely drain the refrigerant charge, using a refrigerant
recovery unit. After detection and repair check the charge with
the unit off, drain the system and recharge the full amount of
liquid refrigerant (see Table I) on the suction and discharge side.
- The refrigerant container used must contain a minimum of 10%
of its initial charge.
WARNING:
If brazing is to be done, the refrigerant circuit must be filled with
nitrogen.
Combustion of refrigerant produces toxic phosgene gas.
IMPORTANT:
- Never use the compressor as a vacuum pump.
- Always add refrigerant via the suction line.
- Refrigerant must be added very slowly.
- The complete refrigerant charge must never be filled into the
suction line.
- Do not overcharge the system with refrigerant.
Electronic control
Operation and control of all units is carried out via the electronic
control.
The instructions supplied with the control include comprehensive
descriptions.
PRO-Dialog Plus electronic control
PRO-DIALOG Plus is an advanced numeric control system that
combines complex intelligence with great operating simplicity.
PRO-DIALOG Plus constantly monitors all machine parameters
and safety devices, and precisely manages the operation of
compressor and fans for optimum energy efficiency.
It also controls the operation of the water pump.
A powerful control system
The PID control algorithm with permanent compensation for the
difference between entering and leaving water temperature and
anticipation of load variations regulates compressor operation for
intelligent leaving water temperature control.
To optimise power absorption, the PRO-DIALOG PLUS
automatically re-calibrates the set point of the entering water
temperature based on the outside air temperature to one of the two
pre-set values (occupied building and of an unoccupied building for
example).
PRO-DIALOG Plus control is auto-adaptive for full compressor
protection. The system permanently optimises compressor run
times according to the application characteristics (water loop
inertia), preventing excessive cycling. In most comfort air
conditioning applications this feature makes a buffer tank
unnecessary.
Clear and easy-to-use control system
The operator interface is clear and user-friendly: LEDs and two
numeric displays ensure immediate verification of all unit operating
data.
10 menus offer direct access to all machine controls, including a
history of possible faults, for rapid and complete chiller fault
diagnosis.
Extended communications capabilities
PRO-DIALOG Plus allows remote control and monitoring of the
unit through a wired connection: start/stop, cooling/heating mode
selection (only 30RH unit), power demand limit or dual set-point
and customer safety lock.
The system permits remote signalling of any general anomaly for
each refrigerant circuit.
Three independent time schedules permit definition of: chiller
start/stop, operation at the second set-point (e.g. unoccupied
mode), and operation at low fan speed (e.g. during the night).
This option also permits cascade operation of two units and
remote control via communication bus (RS 485 serial port).