IST-2126.KM03.01
Istruzione / User’s Manual / Manuel d’utilisation
Pag.4/8
GECA S.r.l. Via E.Fermi, 98 GUSSAGO ( BS )
Tel: 030/3730218 Fax: 030/3730228
FUNCIONAMIENTO.
Nota:
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EN
DESCRIPTION
The
CTR21
is a gas detector for heating plants, with a catalytic sensor for flammable gas. The unit is for wall instal-
lation and the protection code is IP44. It is normally powered at 230 AC and/or 12÷24VAC/DC.
Two different models are available and the only difference is the calibration carried out with specific gas:
The CTR21/M model should be used in plants using Methane.
The CTR21/G model should be used in plants using LPG.
On the front plate the LED bar shows both the working condition and the gas concentration detected by the sensor.
The detector is supplied with two alarm levels with sealed-type outputs relays and with tension-free change over
contacts. Furthermore it has an auxiliary outputs relays in positive security for FAULT situation and an auxiliary input
(
AUX
) connectable to
our Manual NC Resetting valve with Positioning Sensor
.
Fig. 1
shows a typical mains supply wiring diagram with alarm siren and normally closed solenoid valve.
OPERATIONAL DESCRIPTION
Preheating
: when the central unit is supplied, the yellow LED starts to flash and it means the sensor is heating.
After 60 seconds, the green LED switches on and it means the normal working.
NORMAL OPERATING
: the detector reads the gas concentration through the internal sensor
1
st
Red LED:
it illuminates if the gas concentration exceeds
5% LIE.
2
nd
Red LED (ALARM 1):
it illuminates if the gas concentration exceeds
10% LEL; if within 4 seconds the gas is
not reduced, the
PREAL.
relay will activate. This relay is normally used as a prealarm using a siren (
SE301A).
3
rd
Red LED:
it switch on if the gas concentration exceeds
20% LEL; if the gas persists, the 4
th
red LED
ALARM 2
switches on within 30 seconds and the
ALARM
relay will activate. It is normally used to stop the gas through the
manual reset solenoid valve (NO or NC) and/or the interruption of the electrical energy.
If it has been installed a manual reset solenoid valve N.C. with magnetic sensor (mod. VR420÷VR480) connected to AUX input, in the case that the
gas is still open, the yellow LED and the FAULT Relay will activate (see FAULTS section).
RESET Key:
The alarm condition remains latched, LEDs and relays remain activated, even if the gas concentration
is reduced, because the mounted valve is closed. To reset the normal working conditions and/or switch off the siren
push the
RESET
key.
Buzzer:
the
PREAL.
relay will be deactivated and the red LED flashes, only if the gas concentration is higher than
10% of LEL. After 20 seconds, both of them will return in preallarm. (The siren rings)
If it has been used a manual reset solenoid valve NC with the magnetic sensor and in the case that it is snapped, the yellow LED will switch
off and the FAULT relay will be deactivated. (See FAULTS section).
Alarm RESET:
The detector will begin to the normal working, only if the gas concentration is lower than 10% LEL,
the
ALARM
relay will be deactivated and the 3
rd
and 4
th
red LED will switch off. If activated, the
FAULT
relay will be
deactivated and the yellow LED will switch off. (see
FAULTS
sections).
Warning:
Pushing the
RESET
button,
if the gas concentration is higher than F.S.
, it can happen that the first
PREAL.
relay will be deactivated and the first three red LEDs will switch off. The yellow LED will illuminate and the
FAULT
relay will activate. A fault on the sensor is most probable in this case.
Eliminate the alarm’s cause, if the
condition persist pushing the
RESET
key, please consult the
FAULTS
section.
FAULTS
: The detector signal different kind of failures activating the yellow LED and the
FAULT
relay. That is nor-
mally activated. The
FAULT
relay, if necessary, can be used both to signal remotely an occurred damage and to
signal the absence of power to the instrument.
Yellow and green LEDs and FAULT relay activate:
this happens when the catalytic sensor is not working. If this
condition do not change, it will be necessary to replace the unit or to send it to the supplier back to repair.
Yellow, green, 4
th
red LEDs, FAULT and ALARM relays activate:
(
ONLY
after press
RESET
key) this happens
when the catalytic sensor is not working or in few cases when there is a higher gas concentration. In this case the
detector will remain in alarm, as described in the OPERATING>WARNING section. If there are not any gas leaks
and the condition is not change, it will be necessary to replace the unit and/or send it back to the supplier to repair.
Manual reset solenoid valve NC with magnetic sensor failure:
this situation appears ONLY when is installed an electro
valve with magnetic sensor; if it not close the gas, the ALARM relay will activate (gas concentration higher than 20% LIE) and the magnetic
sensor signals to the central unit the this bad working. In this case all led will be lighted and relays will be activated. The failure condition
(yellow led lighted and FAULT relay activated) will be cancelled if pressing the RESET key, the solution of the problem will be visualized.
INSTALLATION
The
CTR21
should be installed according to the national disposition in force on the matter.
Model CTR21/M positioning: Methane
(CH
4
) is a combustible gas lighter than air. Its density related to air is 0.55;
its LEL (
Lower 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 CTR21/G positioning:
LPG
is a gas mixture composed by 20-30% Propane (C
3
H
8
) and by 70-80% Butane
(C
4
H
10
). LPG calibration must be carried out with
Butane
which is a combustible gas heavier than air. Its density
related to air is 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
