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Troubleshooting

If you are experiencing difficulties, having made the checks listed above call Duomo on 01905 797989 for
technical assistance.

The Problem

The Solution

No lights are illuminated on the fascia of the detector

Check that the electrical supply is reaching the
device and that the plug in terminal rail is pushed
into place.

One or all of the sensor fault lights are illuminated

Sensor fault continues to alarm

The detector is subject to repeated alarms

The detector is in a main alarm condition and the
main gas valve is not closing

There is no supply to the solenoid valve

Check that the plug is inserted correctlty.

Check that the sensor wiring is correctly terminated
at both the sensor and detector. Check that 12V DC
is present at the sensor. The green light on the sensor
should be illuminated. Pressing the TEST button it is
possible to check the efficiency of the device and if
the sensors have been connected correctly.

Check that the connections are correct and that
power is supplied to the valve i.e. the valve is not
stuck in the open position. The function of the alarm
relays both Pre-Alarm and Main Alarm can be
checked by pressing the TEST button on the detector
fascia. Check that the main alarm action is configured
for a latching alarm (Switch 2 on 5th DIP switch).

Check the sensor wiring. If the red Overload LED is lit
a short circuit or overload has occurred on the sensor
or the connecting cable.

Ensure that there is not an occassional gas leak. This
may be due to a valve or joint which leaks under
pressure.

The Main Alarm relay is a volt-free contact, therefore
you must connect the live supply to the common of
the main alarm relay contacts terminal 10. A supply
wil then come from terminal 12 to the solenoid valve.

Sensor is connected, but no LED is lit on the front
fascia

Check that the DIP switch is set to the ON position

w:

www.duomo.co.uk

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e:

[email protected]

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01905 797989

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f:

01905 774296

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©

 

Duomo

 

(UK)

 

Ltd.

 

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In case of alarm

Extinguish any naked flames.
Do not switch lights or electrical devices on or off.
Open all windows and doors to increase ventilation.
If the 'ALARM' LED is off the levels of gas have dropped. A responsible, qualified person is now safe to find the cause of
the alarm.
If the alarm sound remains constant, and the cause is not evident or possible to eliminate turn off the emergency
isolation valves to the area and contact your gas provider emergency line. They will advice accordingly.

Summary of Contents for BX444-Mc

Page 1: ...esigned to be installed to EN60079 29 2 Operation When any connected sensor detects the presence of the target gas a 4 20mA signal is sent to the detector proportional to the level of gas The BX444 M then operates a pre alarm relay used for remote sirens or visual indicators If the level of gas continues to rise then the second pre alarm is actuated In the case of explosive gases when the level of...

Page 2: ...les duomo co uk t 01905 797989 f 01905 774296 Duomo UK Ltd 2016 Technical Specification Power Supply Secondary Battery Battery Charger max 2 2Ah Power consumption Power Consumption Relay contact range Pre alarm No 1 Pre alarm No 2 General alarm Sensor fault No of remote sensors Input signal Device precision Reaction time Control Unit Working temperature Start up self diagnostic delay Suitable for ...

Page 3: ...1 actuated This relay output de energises as the level of detected gas exceeds 13 LEL Natural Gas or 200ppm CO 9 2nd Pre Alarm At 13 LEL or 200ppm CO detected Pre alarm relay 2 actuated 10 Main Alarm 20 LEL concentration of gas detected Main alarm relay actuated 11 Fault Indicates a short circuit sensor fault loss of signal or incorrect connection of the sensor In case of a sensor failure the LED ...

Page 4: ...ts down to full operation mode The Green display shows an absence of leakage of gas This indicates a no gas normal condition The Blue display shows percentage of Oxygen This display shows a normal condition The Red display shows an alarm condition where alarm Explosive gas threshold have been reached or passed The Red display shows an alarm condition where alarm Toxic gas threshold have been reach...

Page 5: ...ly down When replacing sensors never seperate a sensing head from its PCB The sensor will have been calibrated using this particular board and therefore will not function correctly with any other Important Notes Always check the wiring before powering up the system Do not test this sensor with anything other than Duomo test gas see BX444 Mc Operation section for further information Concentrations ...

Page 6: ...hence the operation of the gas valve When it is ON the relay is in a normally open state When it is OFF the relay is in a normally closed state NOTE This affects how the gas valve operates and means that you may need to change how it is wired to the BX444 Mc Example shows Positive Safety on Switch 2 on 2nd DIP switch set Main Alarm relay actuation method This can be configured to provide either a ...

Page 7: ...nt Alarm LED s will light to show which zones are in alarm By releasing the the manual TEST button the lights will go out and the audible alarm will cease If a latched alarm function on the main relay is configured this will remain on until the RESET button is pressed 5 In order to conduct a full function test it is essential to use Duomo or equivalent calibrated test gas The maximum concentration...

Page 8: ...Main Alarm can be checked by pressing the TEST button on the detector fascia Check that the main alarm action is configured for a latching alarm Switch 2 on 5th DIP switch Check the sensor wiring If the red Overload LED is lit a short circuit or overload has occurred on the sensor or the connecting cable Ensure that there is not an occassional gas leak This may be due to a valve or joint which lea...

Page 9: ...that the commissioning is successful A Duomo Commissioning Certificate is provided It is prudent to make electrical connection to the detector terminal plus when withdrawn and leave the plug off the detector so that the Duomo Engineer is the first to power up the unit on site This allows wiring to be checked prior to commissioning and avoids damage due to incorrect connection Guarantees for this p...

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