Carbon Monoxide Void Monitoring Shut Off System COSSVM


We've compiled some of the most commonly asked questions about the NoCO carbon monoxide void monitoring automatic shut off system.

Whether you're interested in the installation process or just want to know more about the benefits of the NoCO system, you should be able to find detailed information here.

Dimensions for each unit - Click the Image to Enlarge

NoCO Control Unit

NoCO Void Monitor

NoCO Room Monitor

Installation Instructions & User Guides for each unit.

These simple instructions will enable any Gas Safe Engineer to safely and quickly install your system.

NoCO Control Unit Installation Guide

NoCo Control Unit User Guide

NoCO Void Alarm Installation & User Guide

NoCO Room Alarm Installation & User Guide

Is NoCO just a standard CO Alarm?

No, NoCO is designed for use in a property where there is a boiler installed with a flue routed into a void space (including ‘boxed-in’ flues) to meet the requirements of the gas industry technical bulletin TB008, Edition 3 , Appendix 1, Section 11 which offers the Registered Gas Engineer the option to fit an alternative to inspection hatches if the homeowner or tenant does not want a hatch fitted.
NoCO void alarm is a purpose built snorkel carbon monoxide (CO) alarm to monitor a void space for the presence of any carbon monoxide which may be escaping from a flue contained within a void.
The NoCO range comprises of three elements; a void alarm, room alarm & control unit.
The void & room alarms need to be connected wirelessly to the control unit which should be located near to the boiler, this is called ‘pairing’.
In order to meet the requirements of TB008 each element must be ‘paired’ using the product’s wireless connectivity and the boiler must be wired through the control unit in order to complete the system.

How does NoCO comply with Gas Safe Technical Bulletin 008 (Edition 3)

TB 008 is a guidance document which recommends the use of inspection hatches where this style of flue is installed.
However Appendix 1, Section 11 offers an alternative to hatches (in situations where a property owner or tenant cannot or does not want to have hatches installed) in the form of a CO void monitoring safety shut off system (COSSVM).
NoCO is a system to meet this requirement and will shut down the boiler in the event of CO being detected within a void.

How easy is the system to install?

The NoCO void alarm is very quick and simple to install. Once you have established the route of the void drill a 50mm / 2” diameter hole in the wall or ceiling, fully into the void behind.
Steps must be taken to ensure that cabling, boiler flue or other utilities will not be damaged by the drill.
Ensure the hole is of the minimum diameter throughout to accommodate the full length of the probe and that the alarm (which is positioned within the end of the probe) protrudes through any insulation present.
IMPORTANT: Ensure there is free air clearance around the top of the probe containing the alarm snorkel.
Offer the mounting plate up to the ceiling, ensuring the round boss on the back of the mounting plate locates in the hole previously drilled.
Secure the mounting plate to the ceiling using two suitable pan head screws (not supplied) and fixings appropriate to the material the alarm is being attached to.
Locate the NoCO alarm on the mounting plate, by putting the probe through the hole and rotating clockwise to lock into position. This will automatically activate the battery.
Further information is available from the installation instructions (see the Installation & User Guides at the bottom of this screen).

Can I fit a void or room sensor in the same room as another fossil fuelled appliance such as a gas fire, log burning stove or gas cooker?

If there is another fossil fuel burning appliance in the same room as a room alarm then, in the event that the other appliance spills CO into the room the NoCO unit will switch off the boiler.
The faulty appliance would continue to present a danger to the occupants.
Therefore, in these specific circumstances it is recommended to fit an inspection hatch and use a standard CO detector in place of a NoCO unit.
The option of fitting a NoCO room unit which is ‘paired’ to the system should be given careful consideration if there is a risk of the unit switching off the boiler when a possible CO leak could be coming from another appliance within the same room.

How do I test the Sensors?

Testing the NoCO sensors / alarms: In order to be able to see the Control Unit indicators at the same time as pressing the Test button on the NoCO alarms, it is likely you will need two people to perform this operation.
Place the NoCO alarm onto its base plate
Press the test button on the NoCO alarm
All paired NoCO alarms will sound a pattern of 2 x 4 short beeps and the Alarm LED (red) on the NoCO alarm will flash.
The Alarm LED (red) on the NoCO control unit will flash for 60 seconds.
If the Alarm LED on the NoCO control unit does not flash, the alarms have not been paired. Please repeat the “pairing” procedure.
Testing the NoCO control unit
In order to be able to see the Control Unit indicators at the same time as pressing the Test button on the NoCO alarms, it is likely you will need two people to perform this operation.
Press the test button on the NoCO control unit
The Alarm LED (red) on the NoCO control unit will flash once per second for 10 seconds
All paired NoCO alarms will sound a pattern of 2 x 4 short beeps (but the red alarm LED on the NoCO alarms will not flash)

How many void sensors do I need in an installation?

One void sensor should be installed into each open void space.
If you are in any doubt that the void is clear (i.e. no firebreaks exist) then reasonable steps should be taken to install more than one void sensor, at least one every two meters along the expected path of the flue.

How do I pair the system?

The pairing of any sensor to control unit or room unit should ideally be carried out prior to locating the devices as this is easier to do when the products are first opened out of the packaging.
The “Pair” button is found on the back of the CO alarm.
Using a pen, opened out paper clip or small screw driver, press the “Pair” button of the NoCO alarm once, (with one short press).
The red LED on the back of the alarm will flash and then illuminate for 5 seconds. Within this 5 seconds press the test button on the NoCO control unit.
The Alarm LED (red) and Fault LED (amber) on the NoCO control unit will stop flashing at initial unit pairing.
Repeat process for further alarms, noting that the NoCO control unit is no longer flashing.
Once all the units are interlinked, the network will take a few minutes to establish. It is recommended to wait at least five minutes before testing the units (see below). Note, larger networks will take longer to establish.
Press the reset button on the NoCO control unit which will activate the NoCO control unit to standby mode.
The Control Unit “Boiler Power” LED (green) will illuminate, showing there is mains power to the boiler.
The NoCO Control Unit and NoCO Carbon Monoxide alarms have now been wirelessly interlinked to create a network. This means that in the event of a carbon monoxide leak the NoCO alarms will sound to warn you of the danger and your NoCO Control Unit will switch off your boiler.

What is the guarantee on the NoCO products?

The NoCO range has a 2 year guarantee from the purchase date.
All faulty goods must be returned to the Asbesco Ltd. Proof of purchase may be required.

Can a Homeowner reset the system to re-start the boiler once an alarm has been activated?

No, in the event of the boiler being switched off via the system then the control unit must be re-set by a Gas Safe registered installer as the system may have been triggered by an escape of carbon monoxide; therefore a Gas Safe registered installer needs to check the system.
The Gas Safe registration number will be required in order request the reset procedure via the NoCO Technical Help Line (0844 241 2504)

What are the benefits of NoCO products versus fitting inspection hatches?

The NoCO system is quick and easy to install with very little work needed to the property.
The system will, in the event of CO being detected within a void, switch off the faulty boiler therefore stopping the source of the CO and thus preventing any further risk to life.
Once installed, the system looks like a standard smoke or CO detector therefore being more aesthetically pleasing than hatches.

What will a NoCo system installation cost?

The cost of the NoCO system is dependent on a number of factors around the flue installation and the quantity of void sensors which may be required.
Fitting NoCO offers many more benefits to both the installer and the homeowner therefore these should be taken into consideration when selecting the appropriate solution to meet TB008.
We believe the cost of installing the NoCO system compares favourably with the fitting of hatches in the same circumstances.

What are the symptoms of CO?

Carbon monoxide is a dangerous, poisonous gas that kills hundreds of people each year and injures many more.
It is often referred to as the silent killer because it has no odour or taste and cannot be seen.
Like oxygen, carbon monoxide enters the body through the lungs during the normal breathing process. It competes with oxygen by replacing it in the red blood cells, thereby reducing the flow of oxygen to the heart, brain and other vital organs.
In high concentrations, carbon monoxide can kill in minutes.
Many cases of reported carbon monoxide poisoning indicate that while victims are aware they are not feeling well, they become disorientated and unable to save themselves by either exiting the building or calling for assistance.
Exposure during sleep is particularly dangerous because the victim does not usually wake up.
Symptoms of carbon monoxide poisoning
The following symptoms may be related to carbon monoxide poisoning which all household members should be made aware of :
Mild Exposure: Slight headache, nausea, vomiting, fatigue (often described as ‘flu like’ symptoms).
Medium Exposure: Severe throbbing headache, drowsiness, confusion, fast heart rate.
Extreme Exposure: Unconsciousness, convulsions, cardio-respiratory failure, death.
Should you suspect carbon monoxide may be affecting you or your family, open the doors and windows of your property to ventilate, turn off your appliances and evacuate the premises. At this time the authorities should be contacted to locate the source of the carbon monoxide before re-entering the building.
The National Gas Emergency line number is 0800 111 999
Medical attention should be sought for anyone suffering the effects of carbon monoxide poisoning (headache, nausea).
Common sources of Carbon monoxide
Oil and gas boilers
Gas fired water heaters
Portable generators
Gas or paraffin heaters
Clogged chimneys
Wood or gas fireplaces
Cigarette smoke
Any fossil fuel burning appliance
Vehicle exhaust fumes
WARNING: This NoCO carbon monoxide alarm is not a combustible gas alarm, nor a smoke alarm.
Please install the proper alarms to detect combustible gases, or smoke. This alarm system should not be seen as a substitute for the proper installation, use, and maintenance of fuel-burning appliances (including appropriate ventilation and exhaust systems), nor the sweeping of chimneys.
WARNING: Do not use this carbon monoxide alarm on an intermittent basis, or as a portable alarm for trying to trace one source of the spillage of combustion products from fuel-burning appliances or from chimneys.

Is the Packaging shown on the website just for Illustration?

As the NoCO system can consist of a Control Unit and any combination of void and room sensors up to a maximum of 49 sensors, the box and packaging shown on the website are merely for illustration purposes otherwise we would need a huge number of differently sized printed boxes which is not in line with our environmental policy. All units will be dispatched in plain cover.

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  • A Control Unit and 2 sensors should take no more than 3 hours to install