23
11 - SAFETY FUNCTIONS
Alarms 01/02
17:00 01/01/2023
AV06 - A2L protection
mode
A12h
Gas detector No.001
Reset: NO
Days since the last
reset: 00000
11.4. R-454B Refrigerant leak detector
(standard)
The R-454B refrigerant is selected on the screen CU12 of the group
G. GENCONFIG = a. Unit Confi g. (protected by level 3 password)
The “A2L sensor” (leak detector for R-454B) is also activated on
this screen.
CS14
A2L mitigation
Time ret. AL: 0180s
%LFL AL: 050.0%
%LFL reset: 010.0%
%Fan Prot. Mode: 100%
The screen CS14 of the group G. GENCONFIG = e. Safety Confi g.
shows the parameters of mitigation in case of refrigerant leakage:
In group G. GENCONFIG = e. Safety Confi g. it is possible to check
the value of these parameters:
Screen Parameter R-410A R-454B
CS12
Start value of the alarm of low pressure
safety
2.0 bar 1.7 bar
CS12
Final value of the alarm of low pressure
safety
4.0 bar 3.6 bar
The working pressures of the cooling circuits are automatically
adjusted according to the type of refrigerant.
In group G. GENCONFIG = b. Defrost Confi g. it is possible to
check the value of these parameters:
Screen Parameter R-410A R-454B
CD09 Setpoint to start the defrosting 5.6 bar 5.0 bar
CD09 Setpoint to end the defrosting 33.0 bar 30.4 bar
CD04
Setpoint for start of defrosting by
minimal pressure
2.5 bar 2.2 bar
• The parameter “Time ret. AL” (by default, 180 seconds) allows
setting the delay time so that when a warning appears on
the sensor it does not become an alarm. After this period the
PROTECTION MODE will be activated.
• The parameter “%LFL AL” (by default, 50%) allows to adjust the
percentage of the LFL from which the refrigerant leak failure
occurs (ON of the hysteresis cycle). With this value the unit starts
operating in PROTECTION MODE.
In any case, alarms will be maintained until they are reset from the
Graphic terminal (manual reset).
The alarms related to the leak detector are:
• AL86: A2L sensor failure.
• AL87: Refrigerant leakage, within the defi ned hysteresis cycle.
• AL88: Critical alarm, refrigerant leakage and failure of the indoor
fan (communication, sensor, etc).
Due to the A2L category of R-454B refrigerant (lightly fl ammable),
the units that incorporate this refrigerant require the installation of a
leak detector. This detector uses infrared instead of semiconductor
technology with no need of calibration (self-calibration), with very
fast time response, and high lifetime (life cycle: 15 years).
This detector is installed on a panel next to the supply fans. This
position ensures the correct reading of the gas concentration in the
indoor coil.
• The parameter “%LFL reset” (by default, 10%) allows to adjust
the percentage of LFL (Lower Flammability Limit) below which the
refrigerant leak alarm ends (OFF of the hysteresis cycle). With
this value the unit stops operating in PROTECTION MODE.
• The parameter “%Fan Prot. Mode” (by default, to 100%) allows
to adjust the percentage of the airfl ow rate of the indoor fans
(supply and also return if available) when the unit starts operating
in PROTECTION MODE.
The PROTECTION MODE instantly disables the compressors and
support elements, activates the indoor fans (supply and also return if
available) at 100% of airfl ow (parameterizable) and opens the fresh
air damper at 100% (if available). This happens temporarily, as long
as the leak occurs or the sensor is held down with failure. If one
of these two conditions ceases, the unit will return to the operating
mode it had before the leak (ON, OFF, COOLING, HEATING, VENT,
etc.) and the warning of protection mode will disappear.
11.5. R-410A refrigerant leak detector
(optional)
In units with R-410A refrigerant, a leak detector can be connected
on the RS485 Field-bus of the control board, with address 6 (19200
bps, 8 bits, without parity and 2 stop bits).
When a concentration of gas established by parameter is exceeded,
the alarm is activated and the unit is stopped.
The counter of the number of operating hours and days for the
refrigerant gas detector is accessed in the Group of screens H.
SERCONFIG = f. Working Hours (protected by level 2 password).
This information is very important to perform the maintenance tasks
on the leakage detector:
Annual test: To comply with the requirements of the EN378 and
F GAS is necessary to perform a test of the detector every year.
Every 3 years: a calibration is recommended.
Every 5 / 6 years: change the detector element of the sensor and
perform a calibration is recommended.
CU12
Clock card YES
Refrigerant R454B
Gas leak det. NO
A2L Sensor YES
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