Extractive type Gas Detector
Model PD-14
Instruction Manual

Keep this instruction manual where it is readily accessible.
Thoroughly read this instruction manual before using the equipment so it can be used safely
and correctly.
This manual provides information concerning standard specifications. If the specifications ofyour model are nonstandard, refer to the delivery specifications.

Instruction Manual No.
GAE-044
August 2012

Part Names and Functions

Replacement of Sensor Unit

See page 4 to 6.

See page 20 to 21.

Wiring and Connecting
Methods

Maintenance Check andOperation Methods

See page 11 to 14.

See page 16 to 23.

CVVS cable

Indicator
alarm unit

ShieldNon-grounded

Groundterminal

Grounded

Power-supply
groundterminal

Table of Contents

1.

Introduction ............................................................................................................................... 1

2.

Precautions ............................................................................................................................... 23.

Contents of Package................................................................................................................. 3

4.

External Dimensions and Part Names...................................................................................... 4
4-1. Main Unit ........................................................................................................................ 4
4-2. Terminal Block ................................................................................................................ 5
4-3. Flow Diagram ................................................................................................................. 6

5.

Installation ................................................................................................................................. 7
5-1. Installation Method ......................................................................................................... 7
5-2. Mounting of Optional Items .......................................................................................... 10

6.

Wiring Method..........................................................................................................................11
6-1. Wiring work....................................................................................................................11
6-2. Wiring and Connection................................................................................................. 12

7.

Precautions before Use .......................................................................................................... 15

8.

Maintenance Check and Operation Method........................................................................... 16
8-1. Daily Inspection and Periodical Inspection .................................................................. 16
8-2. Preparing Calibration Gas............................................................................................ 17
8-2. Preparing Calibration Gas............................................................................................ 18
8-3. Replacement of Sensor Unit ........................................................................................ 20
8-4. Replacement of Pump Unit .......................................................................................... 22
8-5. Replacement of Filter for Flow Checker (FC-32)......................................................... 23

9.

Specifications .......................................................................................................................... 24

10. Warranty.................................................................................................................................. 25
11. Life Expectancy....................................................................................................................... 26
12. Detection Principle .................................................................................................................. 27
12-1. Catalytic Combustion ................................................................................................. 27
12-2. Hot Wire Semiconductor ............................................................................................ 27
12-3. Thermal Conductivity ................................................................................................. 27
13. Glossary .................................................................................................................................. 28

1. Introduction
Thank you for purchasing PD-14 Extractive type Gas Detector.
In order to ensure the correct and safe operation of this product, be sure to read thismanual before use.
This product detects various types of gas including combustible gas and detects gas
leakage at an early stage in industrial facilities (e.g., gas manufacturing facilities, chemicalplants, paint factories, and power plants),
Following PD-14s are available, according to the gas sensor incorporated.
Model

Detection Principle

PD-14A-D

Hot wire semiconductor sensor

PD-14B-D

Catalytic combustion sensor

PD-14C-D

Thermal conductivity sensor

Maintenance and inspection are indispensable to the reliable performance of the Gas
Detection/Alarm System. Be sure to perform the maintenance checks described in thismanual.

Explanation of Symbols
The following symbols are used to indicate and classify precautions in this manual.

CAUTION

Indicates information that, if not heeded, is likely to result in death orserious injury.
Indicates information that, if not heeded, could possibly result in deathor serious injury.
Indicates information that, if not heeded, could result in minor injury,
or damage to the product.

MEMO

Indicates advice on handling the product.

DANGERWARNING

12. Precautions●●

Read this manual completely and be sure you understand the information provided herein
before attempting to use the product.
Abide by all applicable laws and regulations when using this product.

WARNINGBe sure to ground the product to prevent electric shocks.
If there is a gas leak alarm, take the necessary measures in accordance with yourcompany’s regulations.

CAUTIONAll necessary work for the product including wiring and installation should be carried out
by suitably trained personnel in accordance with applicable code of practice.
Inspection, maintenance and repair of the equipment should be carried out by suitablytrained personnel in accordance with applicable code of practice.
To avoid damaging the explosion-proof structure, never attempt to disassemble thisproduct.
Do not install the product in places or near places where silicone sealant or gas is used.
Otherwise, the performance of the product may be adversely affected.
Be sure to provide a protection cover (optional) if the product is installed outdoors.
Use the product in accordance with applicable laws and regulations.

23. Contents of Package●●

The product is provided with the following items. Make sure that none of these items is
missing.
Although the product is packed and shipped with the utmost care, contact your New Cosmos
representative if there should be any damage or missing items.
Accessories
Detector headGas collector PF-N3 (see note 1)
Flow checker FC-32 (see note 2)
Attachment set (see note 3)
Pressure tight packing (each of dia.13,
13.5, 14, 14.5)
Two washers (dia. 14)
Clamp type B
Four M6 screws
Two joints
Hexagon wrench(each of nominal dia. 2 and 6: see note 4)
Instruction manual (see note 4)

Optional items
Protective cover (see note 5)
Auto drain AD-40 (see note 6)

Note: 1. It is put on the tip of sampling hose in order to drain rain drop/water splash. Do not use thecollector when the sampling is made in ducts, furnaces and closed cabinet.
2. Specifications of the flow checker FC-32 vary according to the requirement. Refer to thespecification sheets for the details.
3. Pressure-tight-packing dia. 15, washer dia. 15, and A clamp are built in the product asstandard.
4. A pair of hexagon wrenches and instruction manual are provided for each order.
5. It is used when the detector is installed outdoor.
6. The auto drain is designed to automatically discard the accumulated moisture from gas
sampling hose from pits/furnaces.

34. External Dimensions and Part Names
4-1. Main Unit

NumberName

Description

1

Casing cover2

Casing3

Sensor unit

Incorporates a gas sensor.

4

Pump unit

Draws sample gas and exhaust it.

5

Ground terminal

Used when grounding the frame.

6

Cable gland

Used for securing the cable. (Size: G 3/4)

7

Gas inlet

Inlet for sampled gas. (Size: Rc 1/4)

8

Gas outlet

Exhaust outlet for sampled gas. (Size: Rc 1/4)

9

Hexagon socket
locking screw

Used for securing the cable gland with a hexagon wrench of
nominal diameter 6 mm.

10Hexagon socket bolt

Used for securing the casing cover with a hexagon wrench of
nominal diameter 6 mm.

11

Flow checker FC-32

Prevents dust from entering the gas inlet. (Size: Rc 1/4)

4

4-2. Terminal Block
Terminal Block

Pump powerGas detector

Sensor connector
Terminal block

1 2 3 4 5 6

Ground terminal

O-ringNumberName

Description

1

24V(+)

Pump power supply PA(+)

2

GND

Pump power supply PB(-)

3

A

4

B

5

C

6

D

Gas detector

Ground terminal

Used to ground the frame.

54-3. Flow Diagram

SensorPump

Flow checker
FC-32

Terminal
block

Pump power supply

Gas detector

Main components and functions
1) Sensor: Converts gas concentration detected to an electrical signal. One from thecatalytic combustion sensor, hot-wire semiconductor sensor or thermal
conductivity sensor is on the detector.

2) Pump: Draw the sample gas through sampling pipe from the detection point.

3) Terminal block: Terminal block for external connection.
Refer to 6. Wiring Method for details.

65. Installation
5-1. Installation Method

CAUTIONBe careful not to damage the gas detector when installing. Otherwise, the explosion-poof
performance of the gas detector will be lost.
Use appropriate piping material considering type of gas to be detected.
Maximum length of the piping should be less than 20m. pay attention that the responsetime of the detector shall be delayed when the length of the piping is longer du to transport
time of sampled gas. And the length of the piping should be as short as possible when thetype of gas to be detected is highly absorbent gases.
Do not install the product in the following places.
- Places where the ambient temperature exceeds the operating temperature range (-10
to 50 degrees C)- Places where condensation occurs or water is directly sprayed.
- Places subject to corrosive gas.
- Places where are in direct sunshine.
- Places close to equipment that generates high frequencies or a magnetic field.
- Places where silicone sealant is used or likely to be used.
- Places where silicone gas is used or likely to be used.
Do not install the gas detector or tip of sampling pipe where vapor which contains silicone,or the sensor may be adversely affected.
Install the gas detector in places where it can be maintained and inspected with ease.
Install the gas detector in places free from vibration.
Install the gas detector in places free from sudden temperature changes.
Keep the gas detector free from Impacts.
When installing the gas detector outdoors, be sure to install the protective cover(optional).
Install auto drain (option) when the gas is sampled near the outlet of steam or where likely
to suck the water.
The pressure of gas inlet port should be plus or minus 1kPa and the pressure of outlet
port should be less than 1kPa.

71) Locate the tip of gas sampling pipe to be appropriate for the specific gravity of gas to be
detected. It must also be placed in a location where the target gases are likely to accumulate.
Installing height
Type of gas
Gas heavier than air(example: LPG)
Gas nearly equal to air(example: carbon monoxide)
Gas lighter than air(example: hydrogen)

Installing height
A maximum of 10cm above
the floor. (Height to sensor
guard)
75 to 150cm above thefloor. (Height to sensor
guard)
Near the ceiling

Remarks
Keep a space of approximately
7cm from the sensor guard tip
for maintenance and inspection.
Decide the height by considering
the specific gravity andmounting environment.
Decide the height by consideringarrangements for maintenance.

2) Install the gas detector in places where it can be maintained and inspected with ease.
Following are locations where leaked gas may accumulate and appropriate locations for
installation of gas detectors.

Flow checker FC-32

Gas detector

100 to 150cm

Gas collector

Example of detection at high altitude

Example of detection in pipe and pit

CAUTION
Place the gas collector above the water level.

83) Mount the main unit to the wall with M6 screws. It is necessary to open the casing cover at thetime of wiring and replacing sensor. Install the gas detector in places where the cover opening
angle can be more than 90 degrees. Be sure to install the protective cover (optional) when
mounting the main unit outdoors. (Refer to 5-2. Mounting of Optional Items for details of
optional product.)

Mounting hole

Mounting hole

Mounting holes of the bodyMore than 90 degrees

The size when the casing cover is opened

95-2. Mounting of Optional Items●

Protective coverProtective cover
PW-41
Flow checker
FC-32
M3 screw

Gas collector
Sampling pipe

PF-N3

CAUTION
Secure the casing cover with M3 screws if strong winds are expected.

●

Auto drain AD-40
Auto drain
AD-40

10

6. Wiring Method6-1. Wiring work●

Be sure to provide explosion-proof wiring if the product is used in hazardous places.

CAUTIONAll necessary work for the product including wiring and installation should be carried out by
suitably trained personnel in accordance with applicable code of practice.
Cable work
● Use shielded cables, such as CVV-S (0.75 to 2.00mm2). As needed, to protect fromdamage, lay all cables in protective tubes of metal conduits or carbon steel pipes, or lay
cables in protective structure of metal or concrete duct.
● When using the explosion-proof packing lead-in method, refer to the following table anduse a cable with finished diameter matching the inner diameter of packing. In order toprevent the spread of explosive gas or fire, securely tighten the cable gland.
● It is recommended not to connect two cables together. If it is unavoidable, however,connect them or branch them within the explosion-proof casing of main unit.

Cable outer dia.
10 – 10.4
10.5
11
11.5
12
12.5
13
13.5
14
14.5

Packing
Inner dia.
11.5
12
12
12.5
13
13.5
14
14
14.5
15

WasherInner dia.
11
11
12
12
14
14
14
14
15
15

Clamp

C clamp

Accessory
Optional item

Optional item

B clamp

Accessory
A clamp
Built-in accessory* “A pressure-tight packing of 15 in diameter, a washer of 15 in diameter, and an A clamp”
corresponding to cable of 14.5 in diameter, are built into the standard model.
* Each pressure-tight packing of 13, 13.5, 14 and 14.5 in diameter, two washers of 14 in diameter,and one B clamp are provided with the standard model, to correspond to cables of 12 to 14 indiameter.
* If the cable is less than 12 in diameter, select the corresponding pressure-resistant packing,washer, and clamp from the above table and order them from New Cosmos.

116-2. Wiring and Connection

WARNING
Before opening the casing cover of the gas detector, be sure to turn off the product and all
devices (e.g. indicator unit and signal converter) connected to the product.
If the power is turned ON, the power supply may become a source of ignition.
Be sure to ground the product to prevent electric shocks.
Do not damage the surface of the detector, or the explosion-proof performance may be
adversely affected.

CAUTION
Wire the connecting terminals correctly.
Separate connection cables from other power lines as far as possible.
Connecting power supply and signal wires
1)

Connecting power supply
Provide dedicated breakers, if needed, to lines that are connected to peripheral devices,such as indicator units and signal converters.

2)

Connecting between indicator unit and gas detector
Use appropriate cable for installation site, such as 600V vinyl insulated wire (VI), VCT, orCVV (0.75 to 2.00mm2).

MEMO
The length of wiring should be less than 10 ohm of the single line resistance.
The following are the examples.
0.75mm2 wire: within 400 meter
1.25mm2 wire: within 600 meter
2.00mm2 wire: within 1 kilometer

12

MEMO
If the main unit is grounded on the power supply side, do not connect a shielded cable to theground terminal in the gas detector, or otherwise two-point grounding will result.

CVVS cable

PE-14

Indicator

ShieldGroundterminal
Not grounded

GroundedRefer to the Instruction Manual on each device for details.

13

Ground terminalon power supplysideTypical connection procedure
1)2)

Prepare power supply which can provide 24V DC.
(Do not turn on the power supply before wiring the main unit.)
Loosen the hexagon socket bolts on the four corners of the main unit with provided
hexagon wrench of nominal diameter 6 mm to open the casing cover.

3)
4)
5)
6)

Remove the screws on the cable ground and run cables through it.
Remove the screws on the terminal block.
Connect the positive electrode of power supply to 24 V+ terminal.
Connect the negative electrode of power supply to GND terminal.

7)

Check the power supply codes are securely connected to terminals to complete thepreparation of power supply.
Wire the sensor output terminals.
Tighten the hexagon socket bolts on four corners with hexagon wrench and close thecasing cover.

8)
9)

CAUTION.

When closing the casing cover, make sure not to catch the power supply cord, harness, orO-ring in the casing cover.

14

7. Precautions before Use

CAUTION
Before turning ON any devices (e.g., indicator unit, signal converter) connected to the
product, double check all the connections are correct. Make sure that the gas detector
and indicator unit or signal converter, in particular, are properly connected.

●

In Case of Gas Leakage

DANGER
Without panicking, check that there is no fire around the product. Do not touch any electric
switches under any conditions. Sparks from turning electric switches ON or OFF may
cause ignition.

WARNING
If there is a gas leak alarm, take the necessary measures specified by your company.
If a gas leak occurs indoors, open the windows and doors to ventilate the room.
Check the gas leakage location and promptly take the necessary measures.

15

8. Maintenance Check and Operation Method8-1. Daily Inspection and Periodical Inspection●

Daily inspections are conduced by the user, while periodical inspections are conducted byyour local representative.

Frequency

Checking item

Contents of inspection• Corrosion of the gas detector.
• Corrosion of mounting screws. If a failure isfound, replace the parts.
• Flow rate
Check the flow rate by reading the scale onflow checker FC-32.
The normal flow rate is more than 0.7L/min.

Daily
inspection

At least oncea monthVisual inspection

If the flow rate is decreased, check thefollowing possible causes. If there is no
improvement in the flow rate by replacing
filters, replace suction pump after checking
sampling tip and pipe.

16•

Clogging of sampling tip/gas collector•

Clogging of sampling pipe•

Clogging of filter

Frequency

Checking item

Contents of inspection• Apply inspection gas to the gas detector andcheck the alarm activation.
• Remove the upper cup of flow checker FC-32
and connect to a gas bag as below, and apply
inspection gas.

Gas bagDaily
inspectionMore thanonce every 2
to 3 months

Upper cup

Alarm operation
check with realgas

Flow meter

Gas inlet port

Connect togas detector

Periodical
inspection

At least oncea yearConsult your local representative.

Periodical Inspections
In order to maintain the reliability of the gas detection/alarm system, it is extremely important
to conduct maintenance and inspections.
Moreover, it is necessary to use actual gas (combustible gas or toxic gas), to carefully
conduct inspection and calibration. It is highly recommended that you consider periodical
inspections under a maintenance contract with your local representative.

17

8-2. Preparing Calibration Gas● Calibration gas is used for actual gas inspection.
● The following example shows how to prepare a standard gas of 0.72vol% (40%LEL)
isobutane.

With standard gas cylinder●●

Fill a gas bag with standard gas as shown the figure below.
Evacuate the air from gas bag completely before filling the gas to prevent gas
concentration error due to the air in gas bag.
Gas bag

0.72vol% isobutane
air balance

MEMO●

Use urethane gas bag. Leave for about 30 minutes after filling gas to bring humidity in gas
bag close to the ambient condition before use.

18

Without standard gas cylinder●

Use Gas Calibration Kit (optional item) and pure gas cylinder (isobutane 99 vol% or more).
Dilute isobutane with air to produce calibration gas of 0.72 vol% (40%LEL).

MEMOThis calibration gas can be used to check the alarm function. Check the concentration
by Gas Detector XP-3110 or a similar device before using for calibration.

DANGER
Make sure that there are no flammables nearby when handling combustible gas.

1)

Connect gas bag to pure gas cylinder and fill with gas slightly
more than necessary. Bend back the hose and clamp by
pinchcock to prevent the gas from leaking.

1

Pure gas cylinder(Keep it upright)

2)

3)Connect 10 ml syringe to gas bag and take 7.2 ml of raw gas.
(Take the gas slightly more than necessary and then carefullydischarge the excess gas.)

Connect syringe to the inlet of quantitative pump, and pull thepiston to fill pump with raw gas in the syringe. Remove thesyringe and pull the piston all the way out (100 ml).

2

7.2ml of raw
gas

Gas bag with
raw gas3
Quantitative
pump

4)

Connect empty gas bag to the outlet of quantitative pump andpush the piston. Move the piston back and forth for 9 times to
add air and make dilute gas.

4

If you take 7.2 ml of raw gas and move the piston for 10 times (aback-and-forth motion: 100 ml),
7.2 ml / (100 ml x 10 times) = 0.0072
0.72 vol% dilute gas is made.
Lower explosive limit (LEL) of isobutane: 1.8vol%.
0.72 / 1.8 x 100 = 40.0
40 %LEL dilute gas is made.

Gas bag withdiluted gas

19

8-3. Replacement of Sensor UnitWARNINGBe sure to turn OFF the indicator unit or signal converter before replacing a sensor unit.
The electric power may become a source of ignition.
Do not damage the surface of detector when sliding the sensor unit, or the explosion proof
performance may be adversely affected.

CAUTION
Some sensor types need to rewrite the setting data of the detector. Only your local
representative’s maintenance service members or personnel who have completed amaintenance seminar can replace the sensor unit.
Be sure to handle the sensor unit with care. Do not drop or throw the sensor unit.
Otherwise, the sensor wire may be disconnected or the sensor unit may be damaged.
When removing and mounting the sensor unit, do not twist the harness of sensor
connector.
When closing the casing cover, make sure not to catch the power supply cord, harness, orO-ring in the casing cover.
When replacing the sensor unit, make sure that the wiring and piping are notdisconnected, loosened, or damaged.

20

Sensor unit fixing screws (6, 7)
Sensor unit fixing plate (6. 7)
Sensor connector (3, 8,. 9)
Sensor unit (6, 7)
Sensor box (7)Pump unit (5, 10)

Movement ofpump unit (5, 10)

Pump unit fixing screws (4, 10)

Set the groove on thesensor unit to the dent
on the sensor box and fix
the sensor unit. (7)1)2)

Turn OFF the power supply connected to the product.
Loosen the hexagon socket bolts on each four corners with the provided hexagon wrench of
nominal diameter 6 mm, and open the casing cover. (Refer to 4-1. Main Unit”)
3) Disconnect the sensor connector.
4) Loosen 4 fixing screws of pump unit.
5) Pull the pump unit up and slide to left.
6) Remove 2 sensor fixing screws and remove the fixing plate and sensor unit.
7) Fit a new sensor unit and fix the sensor unit fixing plate, then tighten the screws.
* Set the groove on the sensor unit to the dent on the sensor box and fix the sensor unit.
8) Connect securely to the sensor connector.
9) Place the pump unit back to the same position and tighten 4 screws.
10) Tighten the hexagon socket bolts on each four corners with the provided hexagon wrench of
nominal diameter 6 mm, and close the casing cover of the main unit. (Refer to 4-1. Main Unit)
11) Turn ON the power supply connected to the product.
12) After replacing the sensor unit, it is necessary to perform zero adjustment and span
adjustment again, after applying power for about one week to stabilize the sensor output.
13) Be sure to perform zero adjustment first, followed by span adjustment.
14) If an error message is displayed, refer to 10. Trouble Alarm.

MEMO
●
●

It is possible to replace the sensor unit without removing tube connected to the pump unit.
Return the used sensor unit to your local representative.

21

8-4. Replacement of Pump UnitWARNINGBe sure to turn OFF the indicator unit or signal converter before replacing a sensor unit.
The electric power may become a source of ignition.
Do not damage the surface of detector when sliding the sensor unit, or the explosion proof
performance may be adversely affected.

CAUTION
After replacing the pump unit, make sure that all of the wiring and piping connections are
firmly connected.

Pump fixing screw (4, 6)
Pump unit (5, 6)
Pipes (3, 7)

1)
2)Turn OFF the power supply connected to the product.
Loosen the hexagon socket bolts on each four corners with the provided hexagon wrench of
nominal diameter 6 mm, and open the casing cover. (Refer to 4-1. Main Unit”)
3) Disconnect 2 pipes connected to the pump unit.
4) Loosen 3 fixing screws of pump unit.
5) Remove the pump unit.
6) Fix a new pump unit with 3 fixing screws of pump unit.
7) Connect 2 pipes to the pump unit.
8) Tighten the hexagon socket bolts on each four corners with a hexagon wrench of nominal
diameter 6 mm and close the casing cover. (Refer to 4-1. Main Unit”)
9) Turn ON the power supply connected to the detector.
10) Read the flow rate of flow checker FC-32. The normal flow rate is more than 0.7L/min.

22

8-5. Replacement of Filter for Flow Checker (FC-32)●

If the flow rate returns to normal value (more than 0.7L/min) by removing the bottom filterof flow checker FC-32, the filter is possibly being clogged. Please replace the filter whennecessary according to the procedure described below.

1)
2)
3)
4)

Loosen the fastener ring of flow checker to remove the bottom cup.
Pull the filter downward to remove.
Replace the filter with a new one and fix the bottom cup back on.
Confirm the flow rate is normal value (more than 0.7L/min).

FilterTwist

Fastener ring

Bottom cup

23

9. Specifications

Corresponding
sensor typePD-14A: Hot wire semiconductor
PD-14B: Catalytic combustion
PD-14C: Thermal conductivity

Sampling method

Extractive

Target gas

Depends on the specifications

Detection range

Depends on the specifications

Suction flow rate

More than 0.7 L/min

Explosion-proofclass

Ex d II B+H2 T4 (Japan)

Degree of protection

IP 65

Applicable cable

Cable outer diameter: 10 to 14.5 mm
6-core cable (for power supply, sensor power, sensor output)
CVV-S 0.75 mm2 , 1.25 mm2 or 2.0 mm2* Interconnection resistance should be less than 10 ohms

Operatingtemperature andhumidity• Temperature: -10 to 50 degrees C• Humidity: 10 to 90 %RH (0 to 50 degrees C)* No radical temperature or humidity changes and no condensation

Power supply

24V DC +/- 10%

Power consumption
Dimensions

7W max.
133 (W) x 260 (H) x 132 (D) mm (excluding protrusions)

WeightApprox. 5.2kg

Mounting method

Wall mountThe above specifications are subject to change without notice.
If your specifications are nonstandard, refer to the delivery specifications.

24

10. Warranty
New Cosmos Electric Company Limited (New Cosmos) offers the following as the sole andexclusive limited warranty available to the customer.
This warranty is in lieu of, and customer waives, all other warranties of any kind or nature,
expressed or implied, including without limitation, any warranty for merchantability or fitness
for a particular purpose. The remedies set forth herein are exclusive.
New Cosmos warrants to the original purchaser and no other person or entity (the customer)that the gas detection product supplied by New Cosmos shall be free from defects in materials
and workmanship for a period of one (1) year from the date of purchase. This warranty does
not include consumables, such as fuses, filters, etc. Certain other accessories not specificallylisted here may have different warranty periods.
After examination of an allegedly defective product returned to New Cosmos, with freight
prepaid, should the product fail to conform to this warranty, the customer’s only remedy and
New Cosmos’s only obligation shall be, at New Cosmos’s sole option, replacement or repair ofsuch non-conforming product or refund of the original purchase price of the non-conforming
product. In no event will New Cosmos be liable for any other special, incidental orconsequential damages or losses of any kind whatsoever, including but not limited to, loss ofanticipated profits and any other loss caused by reason of non-operation of the product.
This warranty is valid only if the product is maintained and used in accordance with New
Cosmos’s instructions and/or recommendations. New Cosmos shall be released from all
obligations under this warranty in the event repairs or modifications are made by persons otherthan its own or authorized service personnel or if the warranty claim results from physicalabuse or misuse of the product.

25

11. Life Expectancy
The design period longevity under a general environmental condition of this container isabout five years from purchase. The design life expectancy after the guaranteed term
passes is not the one to guarantee this. It is only a guide when a prescribed gas is proofread
and it uses it. It might be impossible to use between the proofreading and the proofreadingschedule for the next term.
.
The life of the sensor after the date of purchase under a general environmental condition isrecommended in the table below. The sensor may not detect gas correctly with the lapse of
the sensor life. Replace the sensor at intervals of the sensor life.
The life of the sensor is specified on the condition that the sensor is serviced properly andthat the sensor is not exposed to high-density gas or sensor poisoning gas. New Cosmos,
however, does not guarantee the specified life of the sensor.

Model

Detection principle

Sensor life

PD-14A

Hot wire semiconductor

Approx. 5 years

PD-14B

Catalytic combustion

Approx. 3 years

PD-14C

Thermal conductivity

Approx. 5 years

2612. Detection Principle
12-1. Catalytic Combustion
Catalytic combustion occurs on the catalyst even at a gas concentration below the lower limit of
combustion due to the operation of the catalyst applied to the platinum coil. The electricalresistance of the platinum coil increases because of the rise in the temperature at this point. Thisdifference is extracted as deviation voltage in the bridge circuit.
Detection of combustible gases is possible up to the lower explosion limit (LEL).

12-2. Hot Wire Semiconductor
When a metal-oxide semiconductor heated by a platinum coil adsorbs an electron-donating gas,such as a combustible gas, its electron concentration increases and the thermal conductivity ofthe semiconductor improves. As a result, the temperature of the semiconductor falls and theresistance of the platinum wire reduce. This difference is extracted as deviation voltage in thebridge circuit.
The feature of this sensor is its extreme sensitivity at low temperatures, which makes it suitable
for sensitive detection.

12-3. Thermal Conductivity
As compared to when only air is present around the sensor, the heat dissipation state of thedetection piece (heated to around 150℃) to which an inert substance is applied and sintered ona platinum wire varies with the increase or decrease in the thermal conductivity of the gas, andthe temperature of the detection piece changes. This difference is almost proportional to the gas
concentration, and therefore, the difference in the resistance of the platinum wire can beextracted as deviation voltage of the bridge circuit.
Although only gases whose thermal conductivity is different from air can be measured, it ispossible to detect high-concentration gases between 0% and 100% by volume.

27

13. Glossary
Indicator / Alarm unit: A unit that receives signals from the gas detector and indicates gas
concentration and alarms.
Detector:

A unit that detects gas concentration and converts it to electric signals.

Backup power source device: A device that supplies power to the gas detector, indicator / alarm
unit in order to maintain its performance during a power failure.
Flow meter:

A meter to measure air flow in gas sampling pipe.

Gas collector:

A gas collecting probe that enhances gas collection efficiency and blocks
water and dust.

Diffusion type:

A method to detect gas by utilizing convection and diffusion of gas.

Explosion proof construction: A totally enclosed structure. When an explosive gas explodes in acontainer, the container can resist the pressure and prevent the ignition of
explosive gases outside of it.
Preset alarm value:

A preset value for the alarm to go off when gas concentration reaches acertain value.

Gas to be detected:

Gas that is detected and indicated which sets off an alarm.

Detection range:

Range of gas’s concentration that can be indicated and set off an alarm.

Alarm accuracy:

Difference between the preset alarm value and gas concentration when an
alarm actually occurs or as the percentage of the difference compared tothe preset alarm value.

Response time:

Time it takes from when the gas detector is exposed to a gas with aconcentration higher (lower) than the preset alarm value until an alarmgoes off.

Temperature range:

Range of temperature where the equipment can perform its functions.

Maintenance and inspections: Work to guarantee that the equipment perform its required
functions.
Calibration gas:Gas used to calibrate scales of the equipment.

Peak hold:A function to constantly update and hold the peak value of input signals.

Hazardous area:

An area in a plant or facility with a hazardous atmosphere where explosive
gases may mix with air and explode or start a fire. An area where gas may
be present.

Non hazardous area: An area where electric equipment that has no potential to create ahazardous atmosphere.
Hazardous atmosphere: Atmosphere within the explosive limit where explosive gas and air are
mixed.
LEL:

Lower Explosive Limit. The lowest concentration of flammable gas thatwill explode when mixed with air and ignited.

(Quoted from gas detection terms and detector tube gas meter terms used by the Industrial Gas
Detector Alarm Association)

28

Manual Revision History
Edition No.

Date

Revisions

GAE-044

August 201200

Additional copies of this Instruction Manual are available.
Contact the following address for ordering information.

Distributor:

Manufacturer:
New Cosmos Electric Co., Ltd.
2-5-4 Mitsuya-naka Yodogawa-ku
Osaka 532-0036, Japan
Phone 81-6-6309-1505
Fax 81-6-6308-0371
Email e-info@new-cosmos.co.jp
http://www.new-cosmos.co.jp