Installation & Operation Manual Merlin GDP4
Rev: 11 03-21
8
Mute & Reset Buttons
MUTE The mute button is located on the front fascia of the GDP4 and is used to mute the sounder inside the board
when in alarm. The internal buzzer operates at approximately >60db measured 30cm (1ft) from a closed panel. The
mute button is used to mute the sounder inside the board when in alarm.
RESET The reset button is located on the front fascia of the GDP4 and is used to turn the system on and to reset the
system following alarm.
General Maintenance
Cleaning
Keep your gas detector in good working order - follow these basic principles;
Remove any dust/debris from the outer enclosure regularly using a slightly damp cloth.
Never use detergents or solvents to clean your device.
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.
Concentrations of alcohol found in many products may damage, deteriorate or affect the gas sensing
elements such as; wine; deodorants; stain removers and thinners. Other gases and substances to avoid are;
corrosives (i.e. chlorine & hydrogen chloride); alkali metals; basic or acidic compounds; silicones; tetraethyl
lead; halogens and halogenated compounds!
Manual Circuit Simulation Test
When the test button on the circuit board is pressed and held for ~3s the detector will simulate an open circuit to
ensure outputs, alarms, indications and external devices etc. operate as intended in response to gas.
Access to the interior of the detector, when carrying out any work, must be conducted by a competent
person! This test does not check the gas-sensing element itself!
Bump Test (Gas Response Check)
What is a Bump Test?
Gas response checks are often referred to as a ‘bump test’. Bump tests are important to make sure a device is able
to detect a release of gas as early as possible. The aim of the bump test is to make sure a detector is working at its
optimum by briefly exposing the unit to a known concentration of the target gas that usually exceeds the highest
alarm point. If the detector goes into alarm and all signals/outputs activate, then the system is working safely. If the
system fails to operate as intended in an alarm state, the gas detector must not be used until a full inspection and
service has been conducted.
Why is it important?
A detector may visually appear in good working order, but its sensitivity can be inhibited by external factors. Dust,
humidity, temperature fluctuations, cleaning products, contaminants or sensor drift (ageing) can cause a decline in
sensitivity and eventual failure.
