Duomo CHCO User manual

Instruction Booklet
Rev. 3. -02/2019
Product: Duomo CHCO
Natural Gas and Carbon Monoxide detector - TYPE A
96125
THIS IS AN IMPORTANT DOCUMENT. IT CONTAINS INFORMATION REGARDING: INSTALLATION, SAFE AND
PROPER OPERATION AND REGULAR CHECKING OF THIS NATURAL GAS AND CARBON MONOXIDE DETECTOR.

2. Technical specication:
Product description: Type A Gas Detector for Natural
Gas and Carbon monoxide.
Outputs: Alarm relay (Volt-free) for Carbon Monoxide
Alarm relay (Volt-free) for Natural Gas
Conformity: BS EN 50291, BS EN 50194, CEI 216-3,
BS EN 50270, BS EN 61010
Warranty Period: 2 year warranty - extendible to 3
years by registering online
Continuous Power Supply: 230V +/- 10% 50/60Hz.
Power consumption: 3.5 Watts at 230 V.
External Supply Fuse Rating: 5A
Compatible Gas valve: MANUAL RESET ONLY.
See Duomo EVRM Type valves
Protective Rating: IP 42
Working Temperature: From -10ºC up to 40ºC
Operational Humidity Range: 0-90% condensing
Sensor Types:
Carbon Monoxide - Nemoto Electrochemical
Natural Gas - Nemoto Catalytic
CE Certification Number: 96125
Dimensions: L 150mm , W 115mm, D 53mm.
Interconnecting Cable size: 1mm
Maximum permissible output Load: 4A
Alarm Conditions:
Natural Gas Alarm at > 10% LEL.
Table 1 - Carbon Monoxide Alarm thresholds
CO Concentration Without alarm be-
fore (minutes)
With alarm before
(minutes)
30 120 -
50 60 90
100 10 40
300 - 3
1. Application
The Duomo CHCO detects the presence Natural
gas and carbon monoxide using dual sensor tech-
nology.
The Duomo CHCO detector is ideally suited for
people with some physical disability that might de-
lay a manual response to an alarm. It is a xed, wall
mounted system with a permanently connected
230 Volt electrical supply.
The CHCO is tted with an output function for trig-
gering dierent ancillary devices, for example Gas
Shut-o valve. If the apparatus is installed in homes
equipped with gas appliances, the output signal
may be used for triggering a shut-o valve on the
incoming mains gas pipe. Such a valve should re-
quire a manual action for resetting to the open po-
sition - see Duomo Type EVRM Valves.
For CO detection in addition to shutdown of the in-
coming gas supply, the CHCO can also start a Ven-
tilation fan. See Important Note regarding Ventila-
tion fan.
Contents
1. Application
2. Technical Specication
Table 1. Carbon Monoxide Alarm
Thresholds.
3. Layout and Key to components
4. Dimensions
5. Positioning the CHCO
6. Typical Wiring Schematic
7. Operation
8. Ventilation Fan Important Note.
9. Avoiding False Alarms
10. Toxic eects of Carbon Monoxide
Table 2– Health eects of COHb blood
levels on healthy adults
11. Emergency Actions upon alarm
- Natural Gas Alarm
- Carbon Monoxide Alarm
12. Emergency Actions upon alarm
- Other considerations
13. Maintenance
14. Anticipated lifetime of sensor
15. Warranty

41 2 3 5 6 7 8
Det. Gas EN50194 - 50291 230V AC 50/60Hz. Passed 3717R13 S.N. 146291
Det. Gas EN50194 - 50291 230V AC 50/60Hz. Passed 3717R13 S.N. 146291
!
ON
FAULT
ALARM CO
ALARM GAS
D
U
R
A
T
A
6
A
N
N
I
-
D
U
R
A
T
I
O
N
6
Y
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A
R
S
3. Layout and Key to components
1
2
3
4
5
6
7
8
9
10
11
13
Key
1. Product Label. Displays: Gas -European Standard EN50194 & EN50291, serial number, date
and country of manufacture and supply voltage and frequency.
2. Test button. This button should only be used to simulate a gas alarm after installation.
3. Catalytic Natural Gas sensor element.
4. Sounder.
5. Electrochemical Carbon monoxide sensor element.
6. On Light. This light ashes as soon as power is applied. After 100 seconds the light stops
ashing and is permanently lit until power is disconnected.
Note: During the diagnostic warm up phase the CHCO will not detect gas.
7. Fault Light. Becomes lit when either the Natural Gas or the CO sensor element becomes
inoperative.
8. Alarm CO Light.
9. Alarm Gas light.
10. Cable connection Terminals
11. Dome cover on CHCO fascia. Remove to nd Product label.
12. Ax label here to show the ‘Replace by date’.
This sticker must be applied by the installing engineer. The life of this detector is 5
years.
13. Ovolus enclosure - Material ABS Self extinguishing.
12
!
ON
FAU LT
ALARM CO
ALARM GAS
D
U
R
A
T
A
6
A
N
N
I
-
D
U
R
A
T
I
O
N
6
Y
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A
R
S
double gas
CHCO
50
34
150
105
71
84 115
4. Dimensions

5. Positioning the CHCO
Ideally, a CHCO should be installed in every room containing a gas appliance. If this is not
practicable, the gas detector should be installed in the room where a gas escape is most likely to
occur; this would typically be the kitchen, due to the presence of a gas cooker and other gas
appliances.
The CHCO should be installed above the level of a possible gas escape and near the
ceiling (typically < 0.3m from the ceiling), in a place where air movements are not impeded by
furniture and furnishings.
The location should not be vulnerable to impact or splashing during normal routine operations such as
cleaning in the area. For further information see BS EN50292 and BS EN50244
Fuel Burning
Appliance
A A BB DD
C
Flue or Extractor
Canopy
Key to Positioning Diagram
Fuel Burning Appliance: This could be a Fire, Cooker, Boiler, or any other gas red appliance.
Flue or Extractor canopy: Used to remove the products of combustion from the room under normal cir-
cumstances.
Dimension A - 1m
Dimension B - 0.15m
Dimension C - Maximum distance from appliance - 3m CO and 5m Natural Gas.
Dimension D - For Natural Gas < 0.3m - For CO < the distance from the ceiling to the top edge of any open-
able window and any door.
The CHCO resets automatically however any connected devices such as Gas valves must be of a manual
reset type. See Duomo EVRM Gas shut o valves. https://duomo.co.uk/product/evrm-manual-reset-sole-
noid-gas-valve/

1 2345678
Natural Gas
Alarm Relay
Carbon Monoxide
Alarm Relay
Fused and Isolated
Electrical Supply
230V 50/60Hz.
5A Max.
CHCO
Terminal Block
Key
Additional
Audible Alarm
(If Fitted)
Manaul Reset Gas
Shut o Valve
Ventilation Fan
(IF Fitted)
Important Note:
The combined load of all external components
connected to the device must not exceed 4A. For larger
loads auxiliary contactors must be used. Call Duomo
Technical Department for further information.
Typical Wiring Schematic
Ph
N
7. Operation.
This device requires a permanent electrical supply. DO NOT USE A PLUG IN LEAD.
Initial Power up
The green ‘On’light (6) will ash for approximately 90 Seconds. This is the warm up period. During this time
the detector will not sense Gas or Carbon Monoxide.
The green ‘On’light (6) will stop ashing and will remain continuously lit.
To test the detector operation without applying calibrated test gas press the Test Button (2) inside the en-
closure. This test should only be conducted by a competent person. This test is used to establish the correct
operation of connected devices and does not replace the requirement to Test using Calibrated test gas at
least once a year.
Testing with calibrated test gas
Expose the Natural Gas sensor (3) to the a 20% LEL Test Gas. This Gas can be purchased from Duomo.
Expose the Carbon Monoxide sensor to Carbon Monoxide test gas from 30 to 300ppm. Please note the
alarm test times for lower concentrations is extended to meet EN50291. See table 1 of this document.
Once the CHCO sounds the alarm the relevant Alarm light will be lit for whichever gas is detected. Internal
switches or relays may be used for triggering a shut-o valve on the incoming mains gas pipe and to apply
power to a remote alarm beacon or a ventilation fan, or both. Check correct functionality of all connected
devices.
Remove the test gas, the detected level of gas will drop and the CHCO will auto-reset. That is to say the
alarm relays will return to the no gas position. Note: Although the power supply is reinstated to the Gas
valve, due to the type of valve to be used with this detector (Manual Reset Only). see e) of Emergency Actions
other considerations Page
6.

8. Ventilation Fan Important Note:
Any ventilation fan connected to this device must
bring air into the room and not exhaust from it.
Exhaust gases from fuel burning appliances installed
in the home may be drawn back from the ue sys-
tem, if the action of an extractor fan (airow from
inside to outside) is stronger than the ue draught.
In the event of a partially or fully blocked ue, the
extraction fan may increase the release of exhaust
gases into the room, and also the subsequent in-
creased production of carbon monoxide.
A ventilation fan can increase the ventilation rate,
provided that the airow it creates is from outside
to inside. It is essential to establish that any fan used
to increase ventilation is correctly installed to ensure
that the air supply inside the premises is not im-
paired by airow from inside to outside.
9. Avoiding False alarms
This detector is designed to minimise the possi-
bility of nuisance alarms. It is however possible
that the detector could also respond to brief
exhaust gas emissions, for example during the
initial start-up of an appliance. Also, hydrogen acts
as an interferent and can arise from some battery
charging activities and the curing of concrete
or cement under certain circumstances. Volatile
Organic Compounds (VOCs), e.g. alcohols, which
may eventually activate the alarm, can be generat-
ed from use of damp-proong materials or other
coatings containing alkylalkoxysilanes.
If any of the above contaminant gases are likely
to be temporarily produced in the vicinity of the
CHCO detector increase ventilation by open doors
or windows.
Toxic eects of Carbon
Monoxide
Carbon monoxide (CO) is a colourless, odourless,
non-irritating gas classied as a chemical asphyxiant
whose toxic action is a direct result of the hypox-
ia produced by a given exposure - CO is rapidly ab-
sorbed through the lungs, diuses across the alveolar
capillary membrane and is reversibly
bound with haemoglobin as carboxyhaemoglobin
(COHb).
The anity of haemoglobin for CO is over 200 times
its anity for oxygen. This reduces the oxygen carry-
ing capacity of the blood, and has an eect on the
dissociation of oxyhaemoglobin, which further re-
duces the oxygen supply to the tissues. CO is chemi-
cally unchanged in the body, and is eliminated in ex-
pired air. The elimination is determined by the same
factors that applied during absorption. The half-life
while breathing room air is 2 h - 6,5 h depending on
the initial COHb level.
If the CO level in the inhaled air is constant, the level
of COHb in the blood will approach an equilibrium
(Saturation) state after several hours. However, the
rate at which the equilibrium is reached depends on
many factors, e.g. lung ventilation rate (physical activ-
ity) and alveolar capillary transfer, cardiac parameters,
initial blood haemoglobin concentration, barometric
pressure, oxygen and carbon dioxide concentration
in the inhaled air, but the two most important factors
in determining the COHb level are the CO concentra-
tion and the duration of exposure.
Table 2. Health eects of COHb blood levels on
healthy adults
% COHb Eects
0,3 – 0,7 Normal range in non-smokers due to
endogenous CO production
0,7 – 2,9 No proven physiological changes
2,9 – 4,5 Cardiovascular changes in cardiac
patients
4 – 6 Usual values observed in smokers,
impairment in psycho-motor tests
7 – 10 Cardiovascular changes in non-cardiac
patients (increased cardiac output
and coronary blood ow)
10 – 20 Slight headache, weakness, potential
burden on foetus
20 – 30 Severe headache, nausea, impairment
in limb movements
30 – 40 Severe headache, irritability, confu-
sion, impairment in visual acuity, nau-
sea, muscular weakness, dizziness
40 – 50 Convulsions and unconsciousness
60 – 70 Coma, collapse, death
Source: U.S. Environmental Protection Agency
1984
10.

Carbon Monoxide is detected.
If CHCO initiates a Carbon monoxide alarm
signal, and the ALARM CO light is lit, it is
recommended that the following actions are
taken in the order given:
1) keep calm and open all doors and windows
to increase the rate of ventilation, but see also
item a) below.
Stop using all fuel-burning appliances and
ensure, if possible, that they are turned o, e.g.
for gas
appliances, isolate the emergency control
valve; This will already be isolated if connected
to the appropriate terminal on the CHCO.
2) if the alarm continues to be activated, then
evacuate the premises. Leave the doors and
windows open, and only re-enter the building
when the alarm has stopped. In multi-occu-
pancy and multi-storey premises, ensure that
all the occupants are alerted to the risk;
3) get medical help for anyone suering the
eects of carbon monoxide poisoning (see
Table 2.) and advise that carbon monoxide
inhalation is suspected;
4) telephone the appropriate appliance ser-
vicing and/or maintenance agency or, when
necessary, the relevant fuel supplier on their
emergency number or the national Gas Emer-
gency Service Provider, if appropriate, so that
the source of carbon monoxide emissions can
be identied and corrected. Unless the reason
for the alarm is obviously spurious (see item c)
below), do not use the fuel-burning applianc-
es again, until they have been checked and
cleared for use by a competent person accord-
ing to national regulations.
Natural Gas is detected
In the event of a Gas Alarm sounding and the
ALARM GAS light being lit on the CHCO detec-
tor Fascia or the smell of gas even without an
alarm:
Keep calm, and carry out the following ac-
tions, not necessarily in the order given:
− extinguish all naked ames, including all
smoking material;
− turn o all gas appliances;
− do not switch on or o any electrical equip-
ment, including the gas detection apparatus;
− turn o the gas supply at the gas main
control and/or (with a LPG supply) the storage
tank;
− open doors and windows to increase venti-
lation;
− do not use a telephone in the building
where the presence of gas is suspected.
If the alarm continues to operate, even after
an alarm resetting action where appropriate,
and the cause of the leak is not apparent and/
or cannot be corrected, vacate the premises
and IMMEDIATELY NOTIFY the gas supplier
and/or the gas emergency 24 h-service in
order that the installation may be tested and
made safe, and any necessary repair carried
out.
If the alarm stops and the reason for the alarm
having operated is identied, (for example a
gas tap switched on with the burner unlit), af-
ter stopping the gas release and ensuring that
all appliances are turned o, the main gas sup-
ply may be reinstated by manually resetting
the manual reset solenoid valve type EVRM.
see e) Emergency Actions - Other considerations
Emergency actions when:
11.

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 trac 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 re.
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
ues, 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-o 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 identied 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/ .

DECLARATION OF CONFORMITY
Natural gas & Carbon Monoxide detector Art. CHCO
It conforms to the following regulations:
Electromagnetic compatibility
Electrical safety
R
eference Norms
(2014/30/EU – EMC)
according to
CEI-EN50270:2006 “Electromagnetic compatibility. Electrical apparatus for the detection and measurement of
combustible gases, toxic gases or oxygen
”
(2014/35/EU
– LVD)
according to
EN 60335-1:2013 “Household and similar electrical appliances - Safety - Part 1:General requirements”
The above mentioned appliances are manufactured and tested according to Norms: BS EN 50194-1:2009 ”Electrical apparatus
for the detection of combustible gases in domestic premises. Test methods and performance requirements”, BS EN 50291-
1:2010+A1:2012 ”Electrical apparatus for the detection of carbon monoxide in domestic premises. Test methods and
performance requirements” and EN 50271:2010 ”Electrical apparatus for the detection and measurement of combustible
gases, toxic gases or oxygen. Requirements and tests for apparatus using software and/or digital technologies”
RoHS Mark
The above mentioned appliances are designed according to the DIRECTIVE 2011/65/EC (RoHS) and do not contain:
Lead
Mercury
Cadmium
Hexavalent Chromium (Chromium IV)
Polybrominated Biphenyls (PBB)
Polybrominated Diphenyl Ethers (PBDE)
GasTest
Natural gas
Mains Power Supply 230VACwithin 2%of rating
Volume Ratio ofGas Litres input up to 10% ofL.E.L.+/- 3%
Temperature 230Cfor the entire duration of the test +/- 2% of rating
Relative Humidity 45% for the entire duration of the test +/- 10%
Constant Barometric Pressure for the entire duration of the test +/- 1kPa Gas Speed
0.35m/s
Calibration at 10% of L.E.L.+/- 3% tolerance
Carbon monoxide
Mains Power Supply 230VACwithin 2%of rating
Volume Ratio ofGas Litres input up to
Temperature 230Cfor the entire duration of the test +/- 2% of rating
Relative Humidity 45% for the entire duration ofthe test +/- 10%
Constant Barometric Pressure for the entire duration of the test +/- 1kPa Gas Speed
0.35m/s
Calibration according to Norms and below table parameters
30 ppm after 120 minutes
50 ppm after 60 minutes
100 ppm after 10 minutes
300 ppm immediate
Additional notes
The above outlined detector conforms to regulation 2014/30/EU, 2014/35/EU and the CE mark applied on the product refers to this regulation. The product was
subjected to tests using a typical configuration.
Technical Director
Duomo (UK) Ltd
Phillip Wild
Droitwich, December 2017
Droitwich, Worcestershire, WR9 9AH.
16. Declaration of Conformity

DISPOSAL OF OLD ELECTRICAL & ELECTRONIC EQUIPMENT (EU directive 2012/19/EU) This symbol on the product or its packaging
to indicates that this product shall not be treated as household waste. Instead, it shall be handed over to the applicable collec-
tion point for the recycling of electrical and electronic equipment, such as for example: - sales points, in case you buy a new and
similar product - local collection points (waste collection centre, local recycling centre, etc...). By ensuring this product is disposed
of correctly, you will help prevent potential negative consequence for the environment and human health, which could otherwise
be caused by inappropriate waste handing of this product. The recycling of materials will help to conserve natural resources. For
more detailed information about recycling of this product, please contact your local city oce, your house hold waste disposal
service or the shop where you purchased the product. Attention: in some countries of the European Union, the product is not
included in the eld of application of the National Law that applies the European Directive 2012/19/EU and therefore these coun-
tries have no obligation to carry out a separate collection at the “end of life”of the product
Duomo (UK) Limited, 5 The Furlong, Berryhill Industrial Estate, Droitwich, Worcestershire, WR9 9AH,
England, United Kingdom. Telephone: [phone] Email: [email protected].uk website: duomo.co.uk