Control; Control And Safety Devices; Low Pressure Switch; High Pressure Switch - CIAT condenciat CD Instruction Manual

12 - CONTROL

● The compressors are controlled by a thermostat (not supplied by CIAT) or a regulation system delivering one or more
potential-free (dry) NO contacts.
● The fans operate as follows:
All-season operation:
Condensation pressure control by HPR pressure switches triggered in series, high and low speed (80 to 300 models) 1 and 2 fans
(350 to 700 models).

13 - CONTROL AND SAFETY DEVICES

All of the unit's safety devices are grouped under a single safety relay. If a safety device is triggered and stops the unit, look for
the fault and reset the safety device if necessary.
The unit will restart when the minimum time required by the short-cycle protection elapses.
Refer to the summary table on page 10 for information on how to set the safety devices.

13.1 Low pressure switch

This low pressure switch has a safety function. It is connected to the compressor intake pipe, and monitors its low pressure. If the
pressure drops below the setpoint, the power supply is cut to the compressor(s) on the refrigerating circuit in question. Setting/
tripping values: see table on page 10.
Pressure switch with automatic reset; the unit restarts at the end of the short-cycle protection.

13.2 High pressure switch

This high pressure switch has a safety function. It is connected to the compressor discharge pipe, and monitors its high pressure.
If the pressure exceeds the setpoint, the power supply is cut to the compressor(s) on the refrigerating circuit in question.
Deactivation value: see table on page 10.
The high pressure switches are reset manually; reset the pressure switch and wait for the end of short-cycle protection.

13.3 Internal compressor protection

Each compressor is equipped with integral electronic protection which has a safety function. It protects the electric motor against
overheating. If a fault occurs, the circuit in question is shut down.
- Automatic restart once the fault has disappeared and at the end of short-cycle protection.

14 - PRE-COMMISSIONING OPERATIONS

Note: never commission the unit without first reading this manual in full.
● Electrical connection
● Refrigerant connection
● System pressure test
● Finding leaks
● Installing the desiccant cartridge (350 to 700 models)
● Placing under vacuum
● Refrigerant load
IMPORTANT: INFORMATION ON PRESSURE TESTING
● It is forbidden to discharge R410A into the atmosphere, therefore refrigerant connection pressure testing cannot be
carried out using R410A.
● Fill the two refrigerant pipes and the evaporator with nitrogen and helium (if you have a helium detector) up to a
maximum pressure of 10 bar.
● Check all the connections for leaks.
● Always place a regulator between the nitrogen cylinder and the refrigerating circuit.
● Never use oxygen or acetylene instead of R nitrogen. Doing so may result in a violent explosion
● During the tests and when the unit is stopped or operating, the maximum permitted pressure must be less than or
equal to that specified on the name plate. Do not exceed this value.
WARNING: INFORMATION ON TESTING UNDER VACUUM
● Never use the compressor as a vacuum pump; it is not designed for such a purpose. Use a vacuum pump capable of
creating a vacuum of 1 mmHg.

14.1 Pre-commissioning check

● Make sure the liquid valves and outlets are open
● Start up the fan on the air handling unit casing and check that it is slaved to the condensation unit
● Set the control thermostat and check its position (must be positioned on the return or in the room)
● Make sure all the electrical terminals are securely tightened
● Check that the network voltage matches the unit voltage and that its value remains within the authorised limits (+10%/-10%
compared to 400 V nominal voltage, phase shift < 2%)
● Leave the compressor crankcase heater under voltage for a few hours before switching on the compressor
(6 hours)
● Touch the crankcases to make sure that the heaters are operating correctly (they should be warm)
EN - 7
EN
NA 06.130 C