Carrier manual Refrigerant charge and electronic control, 30RA/30RH, Gb, Undercharge

30RA/30RH

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).

GB - 10