AGS Mini Merlin CH4CO User manual

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 1
Mini Merlin CH4CO
Dual Gas Monitor
Methane (Natural Gas) & Carbon Monoxide
User Guide
Please read this guide carefully and retain for future use.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 2
Table of contents
1. About your new Mini Merlin device..................................................... 3
2. Carbon Monoxide (CO) –General Information ................................ 4
3. Natural Gas / Methane (CH4) –General Information....................... 5
4. Features ................................................................................................... 6
5. Technical Specification......................................................................... 7
6. Installation & Location ........................................................................... 8
7. Mini Merlin Circuit Board ....................................................................... 9
8. Power On & Off .................................................................................... 10
9. Building Management System Integration....................................... 10
10. Wiring Applications........................................................................... 10
11. Audible Alarm Characteristics........................................................ 13
12. Maintenance .................................................................................... 13
13. Manufacturer’s Warranty ................................................................ 16

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 3
1. About your new Mini Merlin device
Your new Mini Merlin is a dual gas sensor carefully designed and tested to monitor levels of
natural gas- Methane (CH4) and Carbon Monoxide (CO) in the air.
If there is a dangerous build-up of gas or unsafe levels of carbon monoxide at the sensor, this
device can shut off the gas supply via a gas safety valve and/or a gas fired appliance.
This device has additional features for resetting systems, as well as audible and visual alarms - It
can also be integrated with a Building Management System (BMS).
The information contained within this guide should be referenced for typical installation and
operation only. For site specific requirements that may deviate from the information in this
guide –contact your supplier.
Important Warning Statements
Please take the time to thoroughly read this user’s guide which should be retained for future reference.
The expected lifetime of gas sensor elements is 5 years upon initial power up.
The device will display a message to indicate this time and should immediately be replaced.
It is recommended that this device be commissioned upon installation and serviced annually.
Do not apply lighter gas or other aerosols to the device –this will cause extreme damage.
High concentrations of alcohol/ ethanol found in many products may damage, deteriorate or affect the
gas sensing elements –Avoid exposure near your device.
This device is designed to detect carbon monoxide and natural gas from any source of combustion.
It is NOT designed to detect smoke, fire or other gases and should NOT be used as such.
This device provides early warning of the presence of methane or carbon monoxide, usually before a
healthy adult would experience symptoms. This early warning is possible provided your alarm is located,
installed and maintained as described in this guide.
Never ignore your device when in alarm.
This device requires a continual supply of electrical power –it will not work without power.
This device should not be used to substitute proper installation, use and/or maintenance of fuel burning
appliances including appropriate ventilation and exhaust systems.
This device does not prevent methane or carbon monoxide from occurring or accumulating.
Actuation of your alarm indicates the presence of dangerous levels of Methane or CO.
Seek fresh air supply and contact your local gas emergency service should you suspect a gas leak.
This unit may not fully safeguard individuals with specific medical conditions.
If in doubt, consult a doctor/physician.
Your product should reach you in perfect condition, if you suspect it is damaged, contact your supplier.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 4
2. Carbon Monoxide (CO) –General Information
Carbon monoxide (CO) is a poisonous, colourless, odourless, and tasteless gas. Although it has
no detectable odor, CO is often mixed with other gases that do have an odor. So, you can
inhale carbon monoxide right along with gases that you can smell and not be aware that CO
is present.
SYMPTOMS OF CARBON MONOXIDE POISONING
The following symptoms are related to CO poisoning and should be discussed with ALL
members of the household, facility or person/s frequenting monitored areas.
Mild Exposure:
Slight headache, nausea, vomiting, fatigue, flu-like symptoms.
Medium Exposure:
Severe headache, drowsiness, confusion, increased heart rate.
Extreme Exposure:
Unconsciousness, convulsions, cardio-respiratory failure, death.
If you experience even mild symptoms of CO exposure –consult a doctor/ physician
immediately.
CARBON MONOXIDE PPM LEVELS
This device is equipped with a digital display that shows levels of CO (displayed in PPM: parts
per million).
Dangerous levels:
Generally above 100ppm. This should be treated as an urgent situation.
Medium levels:
Generally between 50ppm to 100ppm. This should be cause for concern and should not be
ignored or dismissed.
Low levels:
Maximum acceptable indoor level of CO is <9ppm.
Anything above this level may cause possible health effects with long-term exposure.
See the specification table (5) for how your device monitors CO.
POSSIBLE SOURCES OF CARBON MONOXIDE
Inside your home or facility, gas appliances used for heating, water heating and cooking are
the most likely sources of CO. Vehicles running in attached garages can also produce
dangerous levels of CO.
CO can be produced when burning any fossil fuel, such as gasoline, propane, natural gas, oil
and wood. It can be produced in any fuel burning appliance that is malfunctioning, improperly
installed or insufficiently ventilated.
Automobiles, gas stoves, water heaters, portable fuel burning heaters, fireplaces.
Blocked chimneys or flues, corroded or disconnected vent pipes.
Vehicles and other combustion engines running in open or confined spaces.
Burning charcoal or fuel in grills in an enclosed area or near the home.
For more information, please visit our website or contact your local AGS distributor.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 5
3. Natural Gas / Methane (CH4) –General Information
Methane gas comes from the earth and it comes from our bodies. Methane is non-toxic and it
can be harnessed as an energy source. However, methane is highly explosive and it can cause
death by asphyxiation. It is important to understand how to deal with the hazards associated
with methane.
Although methane on its own isn't poisonous, it has the potential to become poisonous when
mixed with other substances. That potential exists when natural gas (CH4), which is 97%
methane, is burned in houses, offices and businesses. The burning of natural gas without proper
ventilation can produce carbon monoxide, a deadly gas that is difficult to detect.
SYMPTOMS OF METHANE EXPOSURE
Methane gas is relatively non-toxic and associated with being a simple asphyxiator displacing
oxygen in the lungs. However Methane is extremely combustible.
Exposure to high levels of Methane can cause:
Suffocation
Loss of consciousness
Headache and dizziness
Nausea and vomiting
Weakness
Loss of co-ordination
Increased breathing rate
METHANE LEVELS
The LEL (Lower Explosive Limit) of methane is considered to be 5% BV (by volume of air).
So we call 5% BV (by volume) the same as 100% of the LEL (Lower Explosion Limit).
Your device is equipped with a digital display that shows the level of natural gas in the area
referred to as LEL% (a percentage of the LEL) and will alarm based on the following principle of
gas detection.
In simplified terms, a level of 8% LEL or less on your device is generally considered safe and
acceptable.
For more information, please visit our website or contact your local AGS distributor.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 6
4. Mini Merlin Features
REMOTE SHUT OFF
If this device is connected to remote shut off devices (optional).
When activated, the digital display will indicate that it/they are
activated and will shut off the gas supply if installed and configured to
do so.
END OF LIFE
This indicates that the device requires immediate replacement.
The gas monitoring elements are expected to last for 5 years from
initial installation and power up depending on environmental factors.
POWER UP
Press and hold for 3 seconds when electrical supply is connected.
RESET
To reset after a gas alarm - press the touch button once.
TEST
Press and hold for 3 seconds when powered to test screen
colouration, audible alarm and gas/BMS relay.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 7
5. Specification
Power Supply
110-120VAC, 50-60Hz (Max 3.1VA without load)
Gas Sensor Type
NG: semiconductor
CO: electrochemical
Typical Sensor Measuring Range
NG: 500 ~ 10,000ppm
CO: 0 ~ 1000ppm
Accuracy @ 25 C (77 F)
± 1ppm ± 5% reading
Initial Power Up Time
One minute
Low Level Alarm (pre-alarm)
NG 8% LEL by volume
CO 20ppm
High Level Alarm
NG 10% LEL by volume
CO
20 ppm for 2 hours
50 ppm for 1 hour
100 ppm for 10 minutes
300 ppm for 1 minute
Volt free BMS relays output
0.5A switching current (resistive load)
Operating Conditions
-32 - 122 F; (0 - 50 C) 0 - 95%RH, Non Condensing
Net Weight
8.54oz (242g) approx.
O/All Device Dimensions
95(W)x140(H)x60(D)mm
3.7(W)x5.5(H)x2.4 (D)inch
Installation Standard
Wall mountable
Model No:
Mini Merlin CH4CO

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 8
6. Installation & Location
This device is designed for surface mounting using 2 mounting screws (not supplied) and MUST
be installed by a licensed insured contractor. Mark the location of the two holes needed on
the wall using the back plate as a template. Placing at eye level allows for optimum monitoring
of the digital display screen, or as guide, 5 feet (1.5 meters) from ground level.
Back Plate
Removing the back plate gives access to the circuit board.
Do not remove the Circuit Board!
This will void any warranty.
There are also two ‘knock outs’ for electrical wiring access & a divider to separate low and
high voltage connections.
Recommended Installation Locations
The device should be mounted near the
boiler or gas fired appliance/s such as
domestic and commercial boiler rooms and basements.
When choosing your location, make sure you are able to hear the alarm from all areas.
DO place the device at eye level to optimise monitoring of the digital display.
DO place out of reach of children.
AVOID installation within 6 feet (2 metres) of heating or cooking appliances.
AVOID Installation near any ventilation openings, i.e. vents, chimneys, windows etc.
AVOID installation near ceiling fans, windows or areas exposed to direct weather.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 9
7. Mini Merlin Circuit Board
1. POWER/LINE IN –Mains electrical power input. 110-120v AC
2. VALVE OUT –Gas solenoid valve power output. 110-120v AC
3. AUTO RESET & BUZZER SWITCH –See table below.
4. CO BMS –This will switch when CO reaches the alarm level.
5. NG/ LPG BMS –This will switch when CH4reaches the alarm level.
6. REMOTE SHUT OFF –Closed out as a factory setting and during normal operation, this
input shuts off the gas valve relay in the event of external detectors being triggered.
Switch
Options
OFF
ON
Auto Reset
Switch
DEFAULT
When the power is restored after a power
loss, the unit must be restarted manually
This will instruct the unit to restart
automatically when power is restored.
Buzzer
Switch
The audible alarm will not sound at any
level but the digital display gas level
indicators will remain active.
DEFAULT
The alarm will sound every 15 seconds
during pre-alarm gas levels and
continuously when gas levels are high.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 10
8. Power On & Off
How to turn your device ON
Supply 110-120vAC mains to the [POWER/LINE IN] terminal.
Press and hold the touch button on the front of the unit for 3 seconds.
After initial warm up, the screen will show both NG and CO levels in the area.
To switch your device off - remove or Switch Off the mains power supply.
9. Building Management System Integration
This device can be integrated with a Building Management System (BMS), a home alarm
system, or be used as part of a boiler low voltage safety limit to make or break a circuit on both
gases separately, (valve open or valve closed) depending on the system.
These switches can be used for a variety of purposes including triggering alarm contacts,
operating and external relay for multiple appliance shut-down and generating status signals for
a BMS system.
10. Wiring Applications
Gas Supply Controlled by ~120vAC Solenoid Valve
CAUTION: If you use a gas solenoid valve, please note that
standing pilots will need to be re-lit.
We do not recommend installing a gas solenoid valve with
standing pilots.
Gas Supply Controlled by 24vAC Solenoid Valve
When the GAS VALVE terminal is wired to a normally closed
(NC) gas solenoid valve, the device can be used to isolate
gas supply for multiple appliances.
The diagram shown opposite uses an external transformer (not
supplied) to close a 24vAC gas solenoid valve that could
supply gas to one or more appliances.
CAUTION: If you use a gas solenoid valve, please note that
standing pilots will need to be re-lit.
We do not recommend installing a gas solenoid valve with
standing pilots.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 11
Appliance Limit Circuit
The device can be used to directly shut down a gas appliance when a
fault condition is detected (gas leak), by wiring the
normally closed (NC) and common (COM)
terminals of the low volt BMS switches into
the low voltage safety limit circuit of the
appliance.
If gas is detected, the limit circuit is opened, disabling the appliance.
To connect both CO and NG to the safety limit circuit of an
appliance - wire in series as per the following diagram.
Multiple Appliance Limit Circuit
The device can be used directly to disable multiple gas
appliances when a fault condition is detected (gas leak) by
wiring a multi-pole relay to the GAS VALVE LINE terminal.
Low voltage wiring is to be inserted into the external limit
circuit of a gas appliance.
The Honeywell Relay has a 120vAC primary coil with two sets of switches, each with Normally
Open (NO) and Normally Closed (NC) contacts.
These contacts are rated for up to 12A AFL. They can be used to break either a low or line volt
limit circuits or completely remove power to an appliance.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 12
Pilot Water Heater and Boiler Limit Breaker.
The device can be used to directly shut the pilot of a water heater using a product from Field
Controls. The BMS terminals may also be used to connect to a home alarm system.
Remote Shut Off.
Your device has a facility for remote devices to be connected.
The [Remote Shut Off] terminal is NC (Normally Closed) and will alarm when energised Open.
Remote devices cut off the gas supply
when activated.
To reset the device after a remote shut off has been activated –press the Touch Button.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 13
11. Audible Alarm Characteristics
NO ALARM –Gas concentration levels are safe.
PRE- ALARM –ALARM will ‘Beep’ every 15 seconds / Attention required.
ALARM –Continuous ALARM sound / Immediate attention required.
12. Maintenance
TESTING
To test your device, press and hold the Touch Button for 3 seconds –this will test the audible
alarm, gas indicators and BMS relays.
To keep your device in good working order, you must follow these steps:
DO regularly verify your device is operating as intended by testing at least once a week.
DO carefully remove any accumulated dust from the outer enclosure once a month.
NEVER use detergents or solvents to clean your device –this may permenantly or
temporarily damage the gas sensing elements.
NEVER spray air fresheners, hair spray, paint or other aerosols near the device.
NEVER paint the device. Paint will seal vents and interfere with the device.

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 14

MINI MERLIN CH4CO
USER GUIDE
Rev: 08 05-19 15

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USER GUIDE
Rev: 08 05-19 16
13. Manufacturer’s Warranty
2 Year Limited Warranty
Warranty coverage: The manufacturer warrants to the original consumer purchaser, that this product will be free of
defects in material and workmanship for a period of three (3) years from date of purchase. The manufacturer’s liability
hereunder is limited to replacement of the product with repaired product at the discretion of the manufacture. This
warranty is void if the product has been damaged by accident, unreasonable use, neglect, tampering or other causes
not arising from defects in material or workmanship. This warranty extends to the original consumer purchaser of the
product only.
Warranty disclaimers: Any implied warranties arising out of this sale, including but not limited to the implied warranties of
description, merchantability and intended operational purpose, are limited in duration to the above warranty period. In
no event shall the manufacturer be liable for loss of use of this product or for any indirect, special, incidental or
consequential damages, or costs, or expenses incurred by the consumer or any other user of this product, whether due
to a breach of contract, negligence, strict liability in tort or otherwise. The manufacturer shall have no liability for any
personal injury, property damage or any special, incidental, contingent or consequential damage of any kind resulting
from gas leakage, fire or explosion. This warranty does not affect your statutory rights.
Warranty Performance: During the above warranty period, your product will be replaced with a comparable product if
the defective product is returned together with proof of purchase date. The replacement product will be in warranty for
the remainder of the original warranty period or for six months –whichever is the greatest.
Information on waste disposal for consumers of electrical & electronic equipment. (EEE)
When this product has reached the end of its life it must be treated as Waste Electrical & Electronics
Equipment (WEEE).
Any WEEE marked products must not be mixed with general household waste, but kept separate for the
treatment, recovery and recycling of the materials used.
Please contact your supplier or local authority for details of recycling schemes in your area.
For all correspondence:
AGS Head Office
Tel: [phone]
Fax: [phone]
[e-mail]
American Gas Safety is the owner of this document and reserves all rights of modification without prior notice.