12. Emergency Actions - Other considerations
In addition, the following items may modify the actions recommended above and, where appropriate,
should be taken into consideration at the time of installing the apparatus:
a) It should be recognised that increasing ventilation rates may actually lead to higher levels of indoor
carbon monoxide concentration under certain circumstances. Examples of such an occasion would be
from a nearby vehicle exhaust or during extremely bad traffic pollution, especially in cold weather. It is
therefore possible that outdoor conditions could be a factor in triggering domestic carbon monoxide
alarms.
b) There may be another source of carbon monoxide emission inducing the alarm, for example
– a large amount of tobacco smoke,
– town gas,
– emission from a smouldering fire.
c) The alarm may be induced by other substances. (See 9. Avoiding False Alarms)
d) Particular situations could result in exposure to emissions from neighbouring premises, especially in
multi-occupancy and multi-storey properties. There may be special problems with shared or poorly-sited
flues, for example, which could lead to ingress of carbon monoxide from elsewhere in the same building.
Such possibilities should be fully investigated when installing the apparatus.
e) The CHCO provides an output signal which may be used to activate an ancillary device, such as a ven-
tilation fan or gas shut-off valve. Once triggered, these devices may need to be manually reset, but this
should not be done until the source of carbon monoxide or fuel gas escape has been identified and the
fault corrected.
13. Maintenance
This device should be tested periodically ideally every 6 months but a minimum of every 12 months. The
procedure is described in 7. Operation. In the unlikely event that the CHCO fails its routine test, please
contact Duomo technical department on 01905 797989. Advice will be given as to the best course of
action. You will need to provide the date of purchase and the serial number of the CHCO.
14. Anticipated Lifetime of the CHCO.
From date of supply the CHCO has an anticipated lifespan of 6 years. This will be indicated on the label
placed on the fascia of the device during installation. Dated stickers are provided loose in the packing.
These must be applied by the installer of the device.
The CHCO has an automatic end-of-life feature that raises a fault-warning signal when it is necessary to
replace the apparatus. This actuates when the return signal from either the Natural Gas Sensor or the
carbon monoxide sensor falls outside pre-set values. If the fault light (7. Layout of Components) becomes
lit the unit will fail safe and the CHCO must be replaced.
15. Warranty Period
From date of manufacture the warranty period is 2 years. This is extendible to 3 years by registering this
product online at https://duomo.co.uk/product-warranty/ .
