Installation; Warning; Funtional Testing - Geca ST441M Manuel D'utilisation

ST441 (15.05.2019)
The Yellow LED lights up every 4 seconds (with the Green LED on): to warn that the Sensor has exceeded its life
limit (about 5 years) and the correct operation is no longer guaranteed. The detector continues to operate, but it is
necessary, as soon as possible, to replace it with a new one.
If the Yellow LED is on and the Green is off it indicates more possibilities of fault:
1) if 0mA Output indicates that the "Sensor" is faulty, it will be necessary to replace and/or send the detector to
the supplier for repair.
2) if the Output is > 24mA indicates, or the "Sensor" fault, or a gas concentration higher than 25% LEL. If there
are no gas leaks and the condition does not change, it will be necessary to replace and/or send the detector to
the supplier for repair.
Periodical testing: The verification with Gas/Air mixture, is the only safe method to check the effective operation
of the detector and the correct response to the gas. It is recommended to perform the testing every 6-12 months.
After 2 year, we advise to perform the recalibration of the circuit with Gas/Air mixture as explained later in the
graph FUNTIONAL TESTING.

INSTALLATION

The detector should be installed according to the national disposition in force on the matter.
Model ST441M positioning: Methane (CH
er Explosion Limit) is 4.4% volume. The instrument should be fixed at 30 cm from the ceiling and be placed at 1-1.5
meter from the gas appliance, far from the room corners or from ventilation intakes.
Model ST441G positioning: LPG is a gas mixture composed by 20-30% Propane (C
(C H ). LPG calibration must be carried out with Butane which is a gas heavier than air. Its density related to air is
4 10
2 and its LEL (Lower Explosion Limit) is 1.4% volume. The instrument should be fixed at 30 cm. from the floor and be
placed at 1-1.5 meter from the gas appliance, far from the room corners or from ventilation intakes.
Model ST441B positioning: Petrol / Gasoline vapours are heavier than air. Its density related to air is about 2.8.
The instrument should be fixed at 30÷40 cm from the floor.
Mounting: The Fig. 3 shows the instrument size. It has to be wall-mounted by two screw anchors.
Cable glands: the lower side of the housing has 1 inputs designed for metric cable glands (M16x1.5 that accept
external cables Ø 4÷8 mm). This entry is closed, but it is not
quirements, it must be drilling. To facilitate the operation, it has a centering for the drill bit.
Electric connections: are to be carried out using the three-pole non-reversible and plug-in terminals. (For con-
nections and distance, see also the specific instructions of the control unit, to which the detector must be connect-
ed). We recommend using a shielded 3-wire cable with the shield connected to the earth on the control unit side.
The maximum distance from the control unit to which the detectors can be connected depends on the power supply
(See Table 1) Normally with cables 3x1.5mm

WARNING

Compatibility with other control units: In case of a control unit other than GECA, please use products with
4÷20mA input referred to ground and with compatible operating characteristics (unit in %LEL, minimum operating
voltage, absorption, load resistance etc.). We accept no liability for any malfunction, failure or damage caused
by products not compatible or not we produce.
Average life: In fresh air and in normal working condition the sensor's life is about 5 years from the date of installa-
tion. After this period the yellow LED "FAULT" flashes every 4 seconds, it will be necessary replacing the detector.
Important: Catalytic sensors can operate only in presence of Oxygen. Do not use pure gases or a lighter
directly on the sensor since they could damage it irremediably.
Note: The detector is not able to detect gas leaks occurring outside the room where it is installed, neither inside
walls or under the floor.
Attention: please note that in polluted environments, where vapours of flammable agents, especially solvents,
might be present, the sensor's life can be reduced. Some substances cause a permanent reduction in sensitivi-
ty. Avoid contacts of the sensor with vapours of Silicone compounds (paintings and sealing paste), Tetra-ethyl
Lead and Phosphate esters. Some other substances produce a temporary loss of sensitivity. These "inhibitors" in-
clude Hydrogen sulphide, Chlorine, Chlorinated hydrocarbons and halogenated compounds. The sensitivity is re-
covered after a short period of running in clear air.

FUNTIONAL TESTING

PAY ATTENTION: The following operations, has to be made with extreme attention and by authorized and
trained people; because starting this procedure it will increase mA Output causing the activation of con-
nected alarm devices to the gas Control Unit.
Periodical testing: The Calibration with Gas/Air mixture is the only safe method to check the effective operation of
the detector and the correct response of the detector to the gas. It is advisable to perform the verification of opera-
tion every 6-12 months and every 2 years, if necessary, also proceed to recalibration with Gas/Air mixture.
Operation Check, Zero Adjust, Calibration Check and Full Calibration: are different code protected functions.
To access these functions, it is necessary to open the housing and then insert the relevant "Code" with the F1 and
F2 keys, placed on the PCB mounted in the cover. To have the key pressure recognized, hold pressing it for
around a second (until the Green Led doesn't switch off for a moment). Then the next key can be pressed. In case
of error, the Yellow LED flashes quickly, just wait about 10 seconds and the sequence is automatically cancelled.
Calibration Kit, Sample Gas Bottles (for Calibration Check and Full Calibration) please, only using a mixture:
GECA S.r.l. - Via E. Fermi, 98 25064 Gussago (Brescia) Italy
Istruzione / User's Manual / Manuel d'utilisation
) is a gas lighter than air. Its density related to air is 0.55; its LEL (Low-
4
2
at 12Vdc it is 200 meters and at 24Vdc it is 400 meters.
20%LEL (0.88%v/v) Methane in Air (20.9% Oxygen).
manually breakable, according to the installation re-
Tel. +39 030 3730218 - Fax +39 030 3730228
Pag. 5 / 10
para-
H ) and by 70-80% Butane
3 8