Oldham OLC 20, OLCT 20 User Manual
USER MANUAL
OLC/OLCT 20
Part Number: NPO20GB
Revision: D.0
Gas Detector
The Fixed Gas Detection Experts
2
GAS DETECTION
We are delighted that you have chosen an OLDHAM instrument and would like to thank you for your
choice.
We have taken all the necessary measures to ensure that your instrument provides total satisfaction.
Now it is important to read this document carefully.
EEXXTTEENNTT OOFF RREESSPPOONNSSIIBBIILLIITTYY
* OLDHAM declines its responsibility towards any person for material damage, physical injury or death resulting
wholly or partly from inappropriate use, installation or storage of its equipment resulting from failure to observe
instructions and warnings and/or standards and regulations in force.
* OLDHAM neither supports nor authorises any company, physical or moral person to assume responsibility on
behalf of OLDHAM, even if it is involved in the sale of OLDHAM products.
* OLDHAM cannot be held responsible for direct or indirect damage or be required to pay direct or indirect
compensation resulting from the sale or use of any of its products IF THESE PRODUCTS HAVE NOT BEEN
DEFINED AND CHOSEN BY OLDHAM FOR THEIR SPECIFIC USE.
CCLLAAUUSSEESS CCOONNCCEERRNNIINNGG PPRROOPPEERRTTYY
* Drawings, plans, specifications and information included in this document contain confidential information that is
the property of OLDHAM.
* None of this information may be reproduced, copied, divulged or translated, by physical, electronic or any other
means, nor used as the basis for the manufacture or sale of OLDHAM equipment or for any other reasons without
prior consent from OLDHAM.
WWAARRNNIINNGGSS
* This document is not contractually binding. In the interests of its customers, OLDHAM reserves to modify the
technical specifications of its equipment without notice, in order to improve its performance.
* READ THIS MANUAL CAREFULLY BEFORE FIRST USE OF THE EQUIPMENT: this manual must be
read by any person who is or will be responsible for using, maintaining or repairing this equipment.
* This equipment will only provide the announced performance levels if it is used, maintained and repaired
according to OLDHAM directives, by OLDHAM personnel or by personnel approved by OLDHAM.
GGUUAARRAANNTTEEEE
2 years guarantee in normal conditions of use on parts and technical labour, return in our workshops, excluding
consumables (sensors, filters, etc.)
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CONTENTS
1 Description ................................................................................................... 5
1.1 General .......................................................................................................................... 5
1.2 Main characteristics of the various versions ................................................................. 5
1.3 Mechanical installation of the various versions ............................................................ 6
2 Wiring arrangements .................................................................................. 7
2.1 3-Wire version (OLC 20d, OLCT 20d) ........................................................................ 7
2.2 2-wire versions (OLCT 20d) ......................................................................................... 7
2.3 2-wire Intrinsic Safety versions (OLCT 20i) ................................................................ 8
3 Maintenance ................................................................................................. 9
3.1 Detector OLC 20 ........................................................................................................... 9
3.1.1 Calibration ............................................................................................................... 9
3.1.2 Replacing a sensor on an OLC 20 ......................................................................... 10
3.2 Transmitters OLCT 20 ................................................................................................ 10
3.2.1 Calibration ............................................................................................................. 10
3.2.2 Calibration specifications ...................................................................................... 12
3.3 Replacing a sensor on OLCT 20 ................................................................................. 12
3.4 Disposal of OLC(T) 20 ............................................................................................... 12
4 Spare Parts ................................................................................................. 13
4.1 OLC 20 flameproof gas detector ................................................................................ 13
4.2 OLCT 20 flameproof gas detector .............................................................................. 13
4.3 OLCT 20 Intrinsic Safety detector .............................................................................. 14
5 Accessories ................................................................................................. 15
6 Technical characteristics of OLC 20 ....................................................... 17
7 Technical characteristics of OLCT 20..................................................... 17
8 Specific Instructions for use in Explosive Atmospheres according to
European Directive ATEX 94/9/EC ........................................................ 19
8.1 Specifications for mechanical and electrical installation in Classified Areas. ........... 19
8.1.1 Flameproof detectors (d) ....................................................................................... 19
8.1.2 Intrinsic safety detectors (i) OLCT 20 i ................................................................ 19
4
8.2 Metrological specifications for explosive gas and oxygen measurement detectors ... 20
8.2.1 Technical Specifications and Special Instructions for explosive gas detectors .... 21
8.2.2 Technical Specifications and Special Instructions for Oxygen detectors ............. 25
8.3 Markings ..................................................................................................................... 26
8.3.1 Flameproof certified version: OLC 20d and OLCT 20 d ...................................... 26
8.3.2 Intrinsic safety version: OLCT 20 i ...................................................................... 26
9 Recommendations ..................................................................................... 27
10 EU Declaration of Conformity ................................................................. 29
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1 Description
1.1 General
OLC 20 gas detectors are catalytic type detectors intended for the detection of combustible
gases. They are flameproof certified (OLC 20d).
OLCT 20 gas detectors are 4-20 mA transmitters and are intended for the measurement of
combustible and toxic gases and oxygen. They are either flameproof certified (OLCT 20d)
or intrinsically safe certified (OLCT 20i).
OLC 20s and OLCT 20s are available in ¾ NPT or M25 screw fittings and are designed to
be attached on a junction box or any compatible generic transmitters.
1.2 Main characteristics of the various versions
OLC 20
OLCT 20
LEL
LEL
TOX/O2
Flameproof design
X X X
Intrinsic safety design
X
3-wire cable / Wheatstone bridge
X
3-wire cable / 4-20 mA output
X
2-wire cable / 4-20 mA output
X
Catalytic sensor
X X
Electrochemical sensor
X
Replaceable sensor
X
Replaceable and pre-calibrated sensor
X X
6
1.3 Mechanical installation of the various versions
Please ensure you read the paragraph: Special Specifications for use in Potentially Explosive
Atmospheres in Accordance with European Directive ATEX 94/9/EC
See Appendix 1 for general installation instructions.
Figure 1 : Dimensions
A Dimensions OLC/OLCT 20
Cable length 0.2 m
A
7
C
3
1
3 (+)
1 (-/S)
E
C
B
A
D
1
2
3
1 (S)
2 (-)
3 (+)
B
E D D
A
2 Wiring arrangements
Please ensure you read the paragraph: Special Specifications for use in Potentially Explosive
Atmospheres in Accordance with European Directive ATEX 94/9/EC
2.1 3-Wire version (OLC 20d, OLCT 20d)
Figure 2
A
B C D
E
OLDHAM controller
OLC or OLCT 20
Grounding
Power supply
Signal (I)
2.2 2-wire versions (OLCT 20d)
Figure 3
A
B C D
E
OLDHAM controller
OLC 20 or OLCT 20
Grounding
Power supply
Power supply
Signal
8
Hazardous area
Safe area
C
B
A
2.3 2-wire Intrinsic Safety versions (OLCT 20i)
Figure 4
A B C
OLDHAM controller
OLC 20 or OLCT 20
ZENER Barrier
9
3 Maintenance
The operations and adjustments described in this chapter must be performed
by authorized personnel only as they can affect the appliance's reliability in
detection.
It is prohibited to open the transmitter when energized
3.1 Detector OLC 20
Gas detection instruments are potential life-saving devices. Recognizing this fact, OLDHAM Corporation
recommends that a functional “bump” test be performed on every fixed gas-monitoring instruments as part of
a regular maintenance program. A functional test is defined as a brief exposure of the detector to a
concentration of gas(es) in excess of the lowest alarm set-point for each sensor for the purpose of verifying
sensor and alarm operation and is not intended to be a measure of the accuracy of the instrument.
OLDHAM further recommends that a full instrument calibration be performed using a certified
concentration(s) of calibration gas(es) quarterly, every 3 months.* Calibrations may be necessary more or
less frequently based, for example, on application, field conditions, exposure to gas, sensor technology, and
environmental conditions. The frequency of calibration is best determined by company policy or local
regulatory agencies.
If an instrument fails to operate properly during any functional “bump” test, a full instrument calibration
should be performed successfully prior to use.
These recommendations are based on safe work procedures, industry best practises, and regulatory standards
to ensure worker safety. OLDHAM is not responsible for setting safety practices and policies.
* For new installations it may be prudent to carry out bump tests frequently at first (perhaps weekly),
increasing the time intervals (to, perhaps, monthly or more) as confidence grows with experience in the
installation concerned, on the basis of the maintenance record.
3.1.1 Calibration
On the controller
On the detector
Set the measuring channel to the calibration
position (alarm relays inhibited)
Proceed the zero and span
Set the measuring channel back to the
"normal" position and make sure that it is
working properly.
Apply the calibration cup and perform the
calibration in accordance with the procedure
defined during the training course provided
by OLDHAM or by an OLDHAM’s
authorized person
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3.1.2 Replacing a sensor on an OLC 20
When?
- When the sensor is damaged or cannot be calibrated
- On a preventive basis
How?
- Turn off the relevant measuring channel
- Remove the sensor to be replaced
- Replace it with a new sensor
- Turn on the channel back and check that it operates correctly
(see the following page for more information)
3.2 Transmitters OLCT 20
OLCT 20 gas transmitters are equipped with a pre-calibrated sensor and do not require any
adjustment on installation.
However, as gas detectors are safety equipment, it is recommended to bump test the complete
transmitter after a sensor replacement.
3.2.1 Calibration
After removing the sensor from the transmitter, perform the calibration by using the calibrating
bench provided for that purpose (see CALIBRO’s user manual).
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