portable gas detection services

The detectors GAMMA 652-O/M and GAMMA 652-O/G are gas detector of methane and LPG gas, that warns with an optical and acoustic signal, the presence of gas in the environment.

They are planed to be functioning as detected gas with relay exit.

The detectors serie GAMMA are calibrated to detect gas up to 10% of the L.E.L. (Low Explosion Limit), this threshold can change in base of the environmental conditions but it will not gets over during the first 4 years working, the 15% LEL, after that period the instrument have to be put out of order or re-send to Geca S.r.l. for a complete substitution of the device.

With that aim, the package is provided with a label on which have to be indicated the maturity of correct working period (4 years from installing date); this label have to be compiled by who makes the installation.

The gas detector is provided, on the front panel, by three luminous signalisations:

– GREEN LED (ON): indicates that the instruments is powered

– YELLOW LED (FAULT): Indicates that the gas sensor is damaged

– RED LED (ALARM): Indicates that the gas concentration measured in the air exceeds the alarm threshold

In case of damage, the gas detector is able to signals the malfunction, illuminating in fixed way the yellow led and activating a sound alarm with two seconds’ of intermittence.

In case of alarm the detector illuminating the red led and after 20 seconds the buzzer emits a sound alarm and the relay activates.


The catalytic sensor presents in the gas detector, needs to be heated for about one minute to working in a correct way and for that reason when the detector is lighted on the green led will lighten to indicated that the sensor is in the heating phase. During this time, all the detection functions will be inhibited.


Attention: the installation and the out of service of the instrument must be done by skilled personnel only.

The installation of gas and the possible stopping device must be in according to the national and in force prescriptions law.


The GAMMA 652-O/M for methane should be fixed at a maximum distance of 30 cm from the ceiling; the GAMMA 652-O/G for LPG should be fixed at a maximum distance of 30 cm from the floor.
They should be fixed at a distance comprises from 1 meter and 4 meters by the gas device (kitchen, boiler room, etc…)
Possibly in every room in which there is a gas device and, in the residences with more that one floor, at least one for each floor.
Avoid installing:

Directly over the sink or the gas device
In little locals where can be utilised alcohol, ammonia, spray bottles of gas or other substances with flying solvents.
In low ventilated environments
Near to walls or obstacles that can stop the gas flow from the user to the detector, or near to exhausters or fans that can divert the air flow
In environment in which the temperature can arrive over 40°C or under –10°C
In environment with a lot of humidity or vapours

By using an screwdriver unscrew on the right hand side the instrument and uncover it.

The box cover has to be positioned on the three form point or on the wall, by using the screws and plugs available.



Attention: the electrical connection has to be done with an

under track cable.

The gas detector has to be powered at 230Vac by the terminals 1 and 2 It has to be provided with an device, to be disowned

from the detector and the feeding net, as written in the European standard EN 60335-1.


The detector is provided with an external relay with free tension contacts, capacity of connection 3(1)A 250Vac / 2A 24Vdc.


The gas detector has inside a jumper that permits to select the type of electro-valve to connect that can be Normally Opened type or Normally Closed type.We remind that the valve should be installed on the gas pipes outside the room under control, since protection is useless if a gas leak occurs at the beginning of the gas pipe.


We recommend to contact the installer at least once a year for a general verification

IMPORTANT: Do not use pure gas, such as a lighter, directly on the sensor since the sensor could be irremediably damaged.


After the installation it is possible to check the correct operational of the instrument by pushing for at least 2 seconds the TEST button on the board, in this way all the leds will be alight, the acoustic alarm and the relay will be on for 5 second.

At this point it will be necessary to rearm the electro valve connected.