Bacharach GDC-350 Owner's Manual

Instruction 5909-9000

Operation Manual

Rev. 1 - January 2012

Product Leadership x Training x Service x Reliability

GDC-350 Operation Manual

DISCLAIMER

Under no circumstances will Bacharach, Inc. be liable for any claims, losses, or
damages resulting from or arising out of the repair or modification of this equipment
by a party other than Bacharach service technicians, or by operation or use of the
equipment other than in accordance with the printed instructions contained within this
manual or if the equipment has been improperly maintained or subjected to neglect or
accident. Any of the forgoing will void the warranty.

REVISIONS

Bacharach, Inc. makes no warranty or representation, expressed or implied including
any warranty of merchantability or fitness for purpose, with respect to this manual. All
information contained in this manual is believed to be true and accurate at the time of
printing. However, Bacharach reserves the right to make changes at any time without
notice. Revised copies of this manual can be obtained by contacting Bacharach, Inc.

Should you detect any errors or omissions in this manual, please contact the
company at the following address.

Bacharach, Inc.
621 Hunt Valley Circle
New Kensington, PA 15068-7074
USA

Toll free: 1-800-736-4666
Fax: [phone]
E-mail: [e-mail]
Website: www.MyBacharach.com

In no event will Bacharach, Inc., or its officers or employees be liable for any direct,
special, incidental, or consequential damages resulting from any defect in any
manual, even if advised of the possibility of such damages.

© 2012 Bacharach, Inc.

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IMPORTANT

READ AND UNDERSTAND THIS MANUAL PRIOR TO USING THIS INSTRUMENT.

THIS INSTRUMENT SHOULD BE INSPECTED AND CALIBRATED AT REGULAR
INTERVALS BY QUALIFIED AND TRAINED PERSONNEL. FOR MORE
INFORMATION REFER TO THE “SYSTEM MAINTENANCE” AND “CALIBRATION
PROCEDURE” SECTIONS OF THIS MANUAL.

THIS INSTRUMENT HAS NOT
HAZARDOUS OR EXPLOSION-RATED ENVIRONMENTS. FOR YOUR SAFETY,

DO NOT

EXPLOSION-RATED ENVIRONMENTS).

USE IT IN AREAS CLASSIFIED AS HAZARDOUS AREAS (E.G.,

BEEN DESIGNED TO BE INTRINSICALLY SAFE IN

PURCHASE DATE:

PURCHASED FROM:

WARNINGS

CAUTION: More than one live circuit is associated with this device.

CAUTION: Disconnect power before servicing.

Supply voltage is 24 V (nominal) DC or AC (50/60 Hz).

This product is certified for electrical shock and electrical fire hazard only.

WARRANTY POLICY

BACHARACH, INC. WARRANTS THIS INSTRUMENT TO BE FREE FROM
DEFECTS IN MATERIALS AND WORKMANSHIP FOR A PERIOD OF TWO (2)
YEARS FROM THE DATE OF PURCHASE. INDIVIDUAL SENSOR ELEMENTS
HAVE DIFFERENT WARRANTIES, CHECK WITH FACTORY FOR SPECIFIC
SENSOR WARRANTY. THE WARRANTY STATUS MAY BE AFFECTED IF THE
INSTRUMENT HAS NOT BEEN MAINTAINED AND CALIBRATED AS PER THE
INSTRUCTIONS INDICATED IN THIS MANUAL OR HAS BEEN ABUSED OR
DAMAGED IN ANY WAY. THIS INSTRUMENT IS ONLY TO BE USED FOR
PURPOSES STATED HEREIN.

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SERVICE POLICY

BACHARACH, INC. MAINTAINS AN INSTRUMENT SERVICE FACILITY AT THE
FACTORY. SOME BACHARACH DISTRIBUTORS / AGENTS MAY ALSO HAVE
REPAIR FACILITIES, HOWEVER, BACHARACH ASSUMES NO LIABILITY FOR
SERVICE PERFORMED BY ANYONE OTHER THAN BACHARACH PERSONNEL.
REPAIRS ARE WARRANTED FOR 90 DAYS AFTER DATE OF SHIPMENT
(SENSORS, PUMPS, FILTERS AND BATTERIES HAVE INDIVIDUAL
WARRANTIES). SHOULD YOUR INSTRUMENT REQUIRE NON-WARRANTY
REPAIR, YOU MAY CONTACT THE DISTRIBUTOR FROM WHOM IT WAS
PURCHASED OR YOU MAY CONTACT BACHARACH DIRECTLY.

IF BACHARACH IS TO DO THE REPAIR WORK, SEND THE INSTRUMENT,
PREPAID, TO BACHARACH, INC. AT THE FOLLOWING ADDRESS.

BACHARACH, INC.
621 HUNT VALLEY CIRCLE
NEW KENSINGTON, PA 15068
ATTENTION: SERVICE DEPARTMENT

ALWAYS INCLUDE YOUR RMA #, ADDRESS, TELEPHONE NUMBER, CONTACT
NAME, SHIPPING/BILLING INFORMATION AND A DESCRIPTION OF THE
DEFECT AS YOU PERCEIVE IT. YOU WILL BE CONTACTED WITH A COST
ESTIMATE FOR EXPECTED REPAIRS PRIOR TO THE PERFORMANCE OF ANY
SERVICE WORK. FOR LIABILITY REASONS, BACHARACH HAS A POLICY OF
PERFORMING ALL NEEDED REPAIRS TO RESTORE THE INSTRUMENT TO
FULL OPERATING CONDITION.

PRIOR TO SHIPPING EQUIPMENT TO BACHARACH, CONTACT OUR OFFICE
FOR AN RMA # (RETURNED MERCHANDISE AUTHORIZATION). ALL
RETURNED GOODS MUST BE ACCOMPANIED WITH AN RMA NUMBER.

PACK THE EQUIPMENT WELL (IN ITS ORIGINAL PACKING IF POSSIBLE), AS
BACHARACH CANNOT BE HELD RESPONSIBLE FOR ANY DAMAGE INCURRED
DURING SHIPPING TO OUR FACILITY.

NOTICES

COPYRIGHTS: THIS MANUAL IS SUBJECT TO COPYRIGHT PROTECTION; ALL
RIGHTS ARE RESERVED UNDER INTERNATIONAL AND DOMESTIC
COPYRIGHT LAWS. THIS MANUAL MAY NOT BE COPIED OR TRANSLATED, IN
WHOLE OR IN PART, IN ANY MANNER OR FORMAT, WITHOUT THE WRITTEN
PERMISSION OF BACHARACH, INC.

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TABLE OF CONTENTS

1. OVERVIEW ................................................................................................................ 1

1.1. General Description ............................................................................................ 1

1.2. Key Exterior Components ................................................................................... 1

1.3. Key Interior Components .................................................................................... 2

1.4. Sensor Aging and Calibration Extending Firmware (CEF) ................................... 3

2. SPECIFICATIONS ..................................................................................................... 3

2.1. Controller Specifications ..................................................................................... 3

2.2. Sensor Specifications ......................................................................................... 5

2.3. Model Designations ............................................................................................ 6

3. INSTALLATION ......................................................................................................... 8

3.1. Sensor Mounting Heights .................................................................................... 8

3.2. Basic Enclosure .................................................................................................. 8

3.3. Remote Sensor Housing for Solid-State Sensors ................................................ 9

3.4. Detailed Wiring Connections (Types A, B, and D) ............................................... 9

3.5. Detailed Wiring Connections (Type E) ...............................................................10

3.6. Wiring the GDC-350 for Power ..........................................................................10

3.7. Wiring Remote Sensors (Voltage and Signal) ....................................................12

3.8. Wiring Relay Connections ..................................................................................12

3.9. Installation Example 1: Type “A” with Enclosed Transformer ..............................13

3.10. Installation Example 2: Type “B” with Remote Solid-State Sensor ....................14

3.11. Installation Example 3: Type “D” with On-Board and Remote Sensors .............15

3.12. Installation Example 4: Type “E” with Two On-Board Sensors .........................16

3.13. Powering On the GDC-350 ..............................................................................16

4. CONFIGURATION AND OPERATION ..................................................................... 16

4.1. General ..............................................................................................................16

4.2. Test Functions ...................................................................................................17

4.3. DIP Switch Settings ...........................................................................................18

4.4. System Jumpers ................................................................................................19

4.5. Adjusting Alarm Setpoints ..................................................................................21

4.6. Relay Time Delays .............................................................................................23

4.7. Temperature Display – Unit of Measure .............................................................25

4.8. Latching Relay Function ....................................................................................25

4.9. LED Digital Display ............................................................................................26

5. CALIBRATION ......................................................................................................... 27

5.1. Calibration Specifications ...................................................................................27

5.2. Frequency Recommendations ...........................................................................27

5.3. Calculating the Span Gas Value ........................................................................28

5.4. Calibrating the On-Board Sensor .......................................................................29

5.5. Calibrating a Second On-Board Sensor .............................................................30

5.6. Calibrating a Remote Solid-State Sensor ...........................................................30

5.7. Calibrating 4-20 mA Signal for Incoming Analog Transmitter .............................32

6. SYSTEM MAINTENANCE........................................................................................ 33

7. COMMON ACCESSORIES, OPTIONS, AND REPLACEMENT PARTS .................. 34

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1. OVERVIEW

1.1. General Description

The GDC-350 is an economical, self-contained gas detector for non-hazardous (non­explosion rated) commercial applications. It is available in two basic configurations:
single-sensor models and dual-sensor models. The sensors can be configured as
one of the following:

x one on-board (A type)
x one remote (B type)
x one on-board and
x two on-board (E type).

A basic system provides LEDs to indicate Power, Fail, Low (Warning) Gas Alarm, and
High Gas Alarm. Also included are an integral audible alarm with door-mounted
silence push-button, audible time delay, field-settable relay time delays and two alarm
relays.

Gas-specific electrochemical sensors for toxic gases and oxygen are available while
MOS solid-state sensors for combustible gases, TVOCs, and refrigerants are also
available. All GDC-350 on-board sensors are packaged as plug-in “smart” sensor
modules to reduce field maintenance time.

one remote (D type)

1.2. Key Exterior Components

Figure 1-1. Standard GDC-350 Components

NOTE: Photos of the GDC-350 in this manual may show the optional

LED digital display and/or the optional splash guard.

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Figure 1-2. Water Tight GDC-350 Components

1.3. Key Interior Components

Figure 1-3. Interior Components of the GDC-350

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1.4. Sensor Aging and Calibration Extending Firmware (CEF)

GDC-350 systems with on-board electrochemical sensors have been programmed
with our CEF (Calibration Extending Firmware). This firmware takes into
consideration the aging of the electrochemical CO, NO and NO
frequent calibrations are acceptable in non-critical applications such as parking
garages. The system tracks the age of the sensor and automatically compensates for
the degraded output of the sensor as it ages.

2. SPECIFICATIONS

2.1. Controller Specifications

Categories/Subcategories Descriptions

sensors so that less

2

Enclosure

Wiring

Type

Dimensions
H x W x D

Weight

Construction

Power

Remote
Sensor

Standard (NEMA 1X) Water Tight (NEMA 4X)

5.25 x 6.75 x 2.63 (in)
133 x 172 x 67 (mm)

5.13 x 7.13 x 4.00 (in)
130 x 181 x 102 (mm)

1.2 lbs (0.6 kg) 1.4 lbs (0.7 kg)

Polycarbonate with
hinged, secured door
(drip resistant)

Polycarbonate with
hinged, secured door
(water tight)

24 V (nominal), DC or AC (50/60 Hz)

500’ maximum distance between controller and
remote sensor using minimum 18 gauge wire

Common set of LED indicators (4) for:

Power, Fail, Low (Warning) Gas Alarm,
High Gas Alarm

Sensor indicators (2) for:

Sensor 1, Sensor 2

4-digit 8-segment LED digital display (optional)

Integral alarm rated 80 dB @ 10’

Push-button to silence audible alarm

Two DPDT dry-contact relays (rated 5 A @ 240 VAC)

Low Gas Alarm “On” Delay (on “make”) 5 min
Low Gas Alarm “Off” Delay

3

(on “break”) 10 min
High Gas Alarm “On” Delay (on “make”) 5 min
Audible Alarm “On” Delay (on “make”) 5 min
Audible Alarm Feature (on/off)

0° to 40° C (32° to 104° F)

0 to 95% RH non-condensing

User
Interface

Control
Settings

2

(DIP Switch)

Environ­mental

Display

Audio

Buttons

Relays

Relays

Audio

Temperature

Humidity

1

System is configured such that all relays are “FAIL SAFE” (relay coils are always

energized in non-alarm state). Relays are “common” to both channels (activated by
either channel).

2

May be set by user

3

Also known as “minimum run time”

1

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Figure 2-1. Standard Enclosure Dimensions

Figure 2-2. Water-Tight Enclosure Dimensions

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2.2. Sensor Specifications

Categories/Subcategories Descriptions

Response: <30 seconds to 90% of signal

response
Temp Range: 0° C to +50° C (operating)
Repeatability: ±10% of set point
Life Span: 2 to 3 years in air (under normal

conditions)
Gases: CO, NO, NO

On-Board
Sensors

Electrochemical
(Gas Specific)

1

, SO2 (gas-specific)

2

Temperature

Range: -20° to 40° C (-4° to 104° F)

Response: <35 seconds to 90% of signal

response

Temp Range: 0° C to +40° C (operating)

Solid-state
Combustibles
(Non-specific)

Repeatability: ±10% of set point
Life Span: 5+ years in air (under normal

conditions)

Gases: E.g., Propane (C

vapors, methane (CH

), gasoline

3H8

) (non-

4

specific combustibles)

Response: <120 seconds to 90% of signal

response

Temp Range: 0° C to +40° C (operating)

Remote
Sensors

Long Term
Drift: < 5% signal loss / month at

ambient temperatures

Solid-state
Refrigerants
(Non-specific)

Repeatability: ±10% of set point
Life Span: 4-5+ years in air
Typical
Refrigerant Gas
Sensors
Available: R11, R12, R22, R123,

R134A, R404A, R407C,
R410A, R422A, R422D,
R438A, and R507

2

Analog transmitter

4-20 mA signal

1

All integral electrochemical gas sensors are packaged as “Smart” sensor modules.

2

Supports any 4-20 mA analog transmitter manufactured by Bacharach.

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2.3. Model Designations

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3. INSTALLATION

3.1. Sensor Mounting Heights

Gas Applications / Types Suggested Mountings

Carbon Monoxide Gas engine exhaust

Nitric Oxide

Nitrogen Dioxide

Sulfur Dioxide All

Refrigerants All

Combustibles

NOTE: Bacharach considers 4 to 6 feet from the floor as the “breathing
zone” when it applies to sensors installed for vehicle exhaust
applications.

Diesel engine exhaust

applications

Propane

Methane

Hydrogen

3.2. Basic Enclosure

4’ to 6’ from the floor

6” from the floor or near likely

spot for leakage

On/near ceiling (within 12”)

There are two exterior
mounting brackets (one
at the top and one at the
bottom of the base of the
enclosure). These may
be used to mount the
enclosure.

Alternatively, there are
four corner mounting
holes in the enclosure.
Remove the screw
securing the hinged door.
Locate the four 3/16”
diameter mounting holes
located inside the system
enclosure base. Secure
the system to any flat
surface through these
mounting holes.

Figure 3-1. Basic Enclosure Mounting Components

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3.3. Remote Sensor Housing for Solid-State Sensors

Figure 3-2. Remote Sensor Housing

3.4. Detailed Wiring Connections (Types A, B, and D)

Figure 3-3. Wiring Connections for GDC-350 Types A, B, and D

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3.5. Detailed Wiring Connections (Type E)

Figure 3-4. Wiring Connections for GDC-350 Type E

3.6. Wiring the GDC-350 for Power

Drill out one or more of the PVC conduit entry hole plugs located at bottom left or right
or top left edge of system enclosure base. If supplying VAC operational power, pull
two wires suitable for low voltage from power source to the terminals 13 and 14. If
supplying VDC, wire to terminals 12 and 13 observing polarity.

Figure 3-5. Proper Wiring Examples

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Figure 3-5. Proper Wiring Examples (Continued)

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Figure 3-6. Improper Wiring Example

3.7. Wiring Remote Sensors (Voltage and Signal)

Three (3) conductor, 16 to 18 gauge, stranded wire is required between the control
panel and the remote solid-state sensor. Under most local electrical codes, low
voltage wires cannot not be run within the same conduit as line voltage wires. 3­conductor, 16 to 18-gauge wire/cable must be shielded when connecting to a remote
analog transmitter. The remote analog transmitter enclosures have several conduit
entry locations (general purpose enclosure).

NOTE: DO NOT use solid-core wire for connection to wiring terminal
strip. Any damage caused by using solid-core wire will void warranty.
Use stranded wire ONLY.

The voltage supplied by the controller to remote solid-state sensors should measure
approximately 5.0 VDC ±2%, at the remote sensor. Voltage supplied by the controller
to remote analog transmitters should measure approximately 24 VDC nominal. This
voltage is factory set at time of manufacturing. If these voltages are not attained after
installation, the wrong gauge wire may have been used or the wiring run is too long.
The maximum distance between the GDC-350 and the remote sensor is 500 feet.

The remote solid-state sensor housing has a 3/4” conduit thread and nut to allow
installation in any standard electrical junction box (to be supplied by the installer).
Connect three low voltage wires between it and the controller and observe polarity.

3.8. Wiring Relay Connections

System relays are dry contacts and designed to operate fan starters or coils to control
equipment that draws more than 5 amps start-up and/or operational current. The
system does not provide any power from these terminals. Dry contacts operate like a
switch to simply activate (switch on) or de-activate (switch off) equipment to be
controlled, such as fan starters.

NOTE: System relays are SPDT (single pole, double throw) thereby
providing one set of usable dry contacts for each relay. Because the
GDC-350 series systems are designed to be fail-safe, any equipment to
be controlled by the system relays should be wired to the “NC” Normally
closed) and “COM” (Common) terminals. The relay coils are normally
energized in non-alarm state for fail-safe operation.

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3.9. Installation Example 1: Type “A” with Enclosed Transformer

Figure 3-7. Sample Type “A” Installation

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3.10. Installation Example 2: Type “B” with Remote Solid-State Sensor

Figure 3-8. Sample Type “B” Installation

NOTE: Wiring between a GDC-350 and the remote sensor (indicated

above) should be 3-conductor, 16 to 18-gauge shielded cable. Observe
polarity because the GDC-350 supplies DC power to the remote sensor.

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3.11. Installation Example 3: Type “D” with On-Board and Remote
Sensors

Figure 3-9. Sample Type “D” Installation

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3.12. Installation Example 4: Type “E” with Two On-Board Sensors

Figure 3-10. Sample Type “E” Installation

3.13. Powering On the GDC-350

Upon application of power, the green LED light indicator(s) will illuminate and the LED
between CH-1 and CH-2 will be blinking but all alarms are disabled for 2 minutes for a
system warm up period. After the warm up period, the system may exhibit gas alarm
condition(s) if one or both of the sensors has not completely stabilized during the
warm up period. This is normal and the length of time the gas alarms exist is
dependent upon the length of time since the unit was last powered up and the state of
the environment it is installed in. After warm up, only the green power LED
illuminates indicating normal operation and the relays are energized indicating normal
“Fail-safe” status.

4. CONFIGURATION AND OPERATION

4.1. General

In the event of a burned-out, damaged or missing solid-state sensor element, the
controller will indicate fail condition on the front door by illumination of the red fail
LED. At this point, both system relays will have reversed state (de-energized) and
anything connected to them will be running continuously. Normal system operation
will not occur until the fault condition has been rectified. The same condition will
occur if the 4-20 mA signal from the remote transmitter is broken or interrupted.

NOTE: Fail condition overrides any system time delays that may have
been set.

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NOTE: Reference photo on page 1 for location of LEDs and test-

In the event of a gas build up beyond the preset low alarm trip point, the “Sen-1” LED
illuminates, the “Low” alarm level LED illuminates and the low alarm relay de­energizes activating anything controlled by it. If a time delay “ON” has been set
(internal DIP switches), then the “Low” alarm LED will “flash” indicating the time delay
has been activated and the low alarm relay will not de-energize until the delay has
timed out. Once the low alarm relay has de-energized, it will re-energize
automatically once the gas alarm condition goes away, unless a time delay “OFF”
(minimum run time - internal DIP switches) has been programmed. The same
procedure applies to the second channel in the case of a two-channel (two-sensor)
system.

In the event of a gas build up beyond the preset high alarm trip point, the “Sen-1” LED
illuminates, the “High” alarm level LED illuminates and the high alarm relay de­energizes activating anything controlled by it. If a time delay “ON” has been set
(internal DIP switches), then the “High” alarm LED will “flash” indicating the time delay
has been activated and the high alarm relay will not de-energize until the delay has
timed out. Once the high alarm relay has de-energized, it will re-energize
automatically once the gas alarm condition has dispatched. The same procedure
applies to the second channel in the case of a two channel (two sensor) system.

buttons.

NOTE: No minimum run time delay is provided for the high alarm relay.

4.2. Test Functions

A momentary test feature is provided to allow the user to test basic functionality of the
circuit. Press the UP push-button (internal) for 5 seconds, the audible alarm will beep
once to indicate it is in the 5 second test function. Release the UP push-button after
5 seconds and an automatic test function will occur.

Alternatively, use the silence push-button on the front door to perform the same
function.

The low alarm relay will de-energize and the low alarm LED on the front door will
illuminate. The low alarm relay will then re-energize while the low alarm LED stays lit
for 10 seconds.

Next, the high alarm relay will de-energize, the high alarm LED on the front door will
illuminate and the audible alarm will activate. The relay will then re-energize but the
high alarm LED and the audible alarm will stay activated for 10 seconds. After
10 seconds, everything resets to normal operating condition.

If a longer test sequence is desired, hold down the UP push-button for 10 seconds to
activate the low alarm relay, high alarm relay, low alarm LED, and high alarm LED for
15 minutes.

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To abort this test, press the internal “UP” push-button or the exterior silence push­button and everything will reset to normal operating condition.

If the GDC-350 is equipped with a digital display, it will indicate “test” during this test
period.

4.3. DIP Switch Settings

Figure 4-1. DIP Switch Settings for Alarms

DIP switches in the “UP” position are “ON”.

Fixed delay durations indicated above are factory default settings. Time
delay durations can be changed by user. See page 23.

“On” delays are enforced upon alarm relay “make” conditions. “Off”
delays are enforced upon alarm relay “break” conditions.

If DIP switch 5 is in the “up” position, the internal audible alarm responds to whatever
commands it is given by the microprocessor in the circuit. If DIP switch 5 and DIP
switch 4 are in the “up” position, the audible alarm responds after the user preset time

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delay function for the audible alarm has timed out. If DIP switch 5 is in the “down”
position, the audible alarm does not respond at all.

The internal audible alarm normally activates with a steady tone when a “high” gas
alarm condition exists. The internal audible alarm normally activates with a pulsing
tone when a fault condition exists. A fault condition could consist of any of the
following:

x Remote solid-state sensor failure (open loop)

x Analog signal from a remote 4-20 mA transmitter is not registering with the

GDC-350.

x Smart sensor board is not plugged into the main board.

Fault conditions automatically override the ON/OFF DIP switch “5” if it
has been set to the “DOWN” position to turn off the audible alarm.

4.4. System Jumpers

There are two banks of jumpers located directly below the DIP switches. One bank of
nine (9) jumpers/18 pins (J7) and one bank of four (4) jumpers/8 pins (J6). These
jumpers allow the user to perform a wide range of set up and calibration functions.
The following table details the jumper settings for each bank of jumpers and explains
the function enabled when these jumper positions are selected.

Always set J6 jumpers first, followed by J7 jumpers.

Jumper 4 (located on J6) is used to set custom time delays for relays
and internal audible alarm. These functions are explained in
Section 4.6.

NOTE: In Figure 4-2, the jumper tab for both banks is covering the “P1”
position.

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Functions J6 J7

Resting (J7 jumpers are disabled) P1 P1

Setting Span Gas Value (On-board Sensor) P2 P2

Perform Zero (Null) Calibration (On-board Sensor) P2 P3

Perform Span Calibration (On-board Sensor) P2 P4

Adjust Low Gas Alarm Ascending Value (On-board Sensor) P2 P5

Adjust High Gas Alarm Ascending Value (On-board Sensor) P2 P6

Adjust Low Gas Alarm Descending Value (On-board Sensor) P2 P7

Adjust High Gas Alarm Descending Value (On-board Sensor) P2 P8

Enable/Disable Current Output P2 P9

Setting Span Gas Value (Remote Sensor) P3 P2

Perform Zero (Null) Calibration (Remote Sensor) P3 P3

Perform Span Calibration (Remote Sensor) P3 P4

Adjust Low Gas Alarm Ascending Value (Remote Sensor) P3 P5

Adjust High Gas Alarm Ascending Value (Remote Sensor) P3 P6

Adjust Low Gas Alarm Descending Value (Remote Sensor) P3 P7

Adjust High Gas Alarm Descending Value (Remote Sensor) P3 P8

Enable/Disable Current Output P3 P9

Custom time delays for relays and internal audible alarm (see page 23) P4 N/A

Figure 4-2. J7 (Top) and J6 (Bottom) Jumper Banks

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4.5. Adjusting Alarm Setpoints

The GDC-350 is configurable as a single or dual channel detector as such there are
two ascending gas alarm set points and two descending gas alarm set points. Almost
all installations of the GDC-350 will use the factory default alarm set points. Default
set points are as follows.

SENSOR LOW ALARM HIGH ALARM RANGE

Caron Monoxide (CO) 25 ppm 100 ppm 200 ppm

Nitric Oxide (NO) 35 ppm 50 ppm 100 ppm

Nitrogen Dioxide (NO2) 0.7 ppm 1.5 ppm 10 ppm

Sulfur Dioxide (SO2) 1.0 ppm 5.0 ppm 20 ppm

Propane (C3H8) 10% LEL 20% LEL 50% LEL

Methane (CH4) 10% LEL 20% LEL 50% LEL

Refrigerants 500 ppm 1000 ppm 2000 ppm

Temperature °C 30 °C 40 °C 60 °C

Temperature °F 75 °F 90 °F 100 °F

If the GDC-350 has been equipped with an LED digital display, set values according
to what is displayed. If the GDC-350 does not have a digital display, you will need to
attach volt meter leads to the two test points (TP1 and TP2) located just below the
high alarm relay (RLY2) on the main circuit board.

Figure 4-3. Locations of Test Points TP1 and TP2

Move the jumper on the lower bank (J6) from its resting position (P1) and place it on
the appropriate jumper position as indicated in the table on the previous page. Next,
move the J7 jumper from its resting position to the desired position. Then use the UP
or DOWN push-buttons to set the desired alarm value.

To make additional changes to the sensor selected via J6, repeat the following steps:

x move J7 to the appropriate position
x use the UP or DOWN push-buttons to set the desired alarm value.

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GDC-350 Operation Manual

Once all alarm settings have been set to desired values, move J7 back to its resting
position P1. Then move jumper J6 back to its resting position (P1) on the lower bank.
All new values will be written to the EEPROM. Refer to the flowchart below.

Figure 4-4. Jumper Settings J6 and J7

Alarm settings for GDC-350 detectors are voltage settings. The range of 0-4.0 VDC is
equal to the full measurement range of the sensor. For example, a CO sensor has a
standard measurement range of 0-200 ppm—therefore, 4.0 VDC = 200 ppm.
Reference the formula below and the table on page 23.

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GDC-350 Operation Manual

Therefore, in this example, the required voltage setting to achieve an alarm set point
of 100 ppm is 2.0 VDC.

VOLTAGE REFERENCE TABLE FOR ALARM SETTINGS

SENSOR /

GAS

MEASUREMENT

RANGE

LOW ALARM

SET VOLTAGE

HIGH ALARM

SET VOLTAGE

CO 0-200 ppm 25 ppm / 0.50 VDC 100 ppm / 2.00 VDC

NO2 0-10 ppm 0.7 ppm / 0.56 VDC 1.5 ppm / 1.20 VDC

O2 0-25.0% Vol 19.5% Vol./ 3.12 VDC 23.0% Vol. / 3.68 VDC

NO 0-100 ppm 25 ppm / 1.00 VDC 50 ppm / 2.00 VDC

SO2 0-20 ppm 2 ppm / 0.40 VDC 5 ppm / 1.00 VDC

Combustibles 0-50% LEL 20% LEL / 1.60 VDC 40% LEL / 3.20 VDC

Refrigerant

Gases

0-2000 ppm 500 ppm / 1.00 VDC 1000 ppm / 2.00 VDC

(R series)

4.6. Relay Time Delays

The GDC-350 offers a wide range of time delay settings that are user configurable. If
the GDC-350 has been equipped with the LED digital display, read the values on the
display as you change them to suit your application. If the GDC-350 does not have a
digital display, you will need a volt meter. The voltage reference is 0-4 VDC.

Attach the volt meter leads to the two test points (TP1 and TP2) located just below the
high alarm relay (RLY2) on the main circuit board.

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GDC-350 Operation Manual

VOLT READING

AT TEST POINTS

0 V N/A 0.58 V 2.9

0.02 V 0.1 0.60 V 3.0

0.04 V 0.2 0.62 V 3.1

0.06 V 0.3 0.64 V 3.2

0.08 V 0.4 0.66 V 3.3

0.10 V 0.5 0.68 V 3.4

0.12 V 0.6 0.70 V 3.5

0.14 V 0.7 0.72 V 3.6

0.16 V 0.8 0.74 V 3.7

0.18 V 0.9 0.76 V 3.8

0.20 V 1.0 0.78 V 3.9

0.22 V 1.1 0.80 V 4.0

0.24 V 1.2 : :

0.26 V 1.3 1.0 V 5.0

0.28 V 1.4 1.2 V 6.0

0.30 V 1.5 1.4 V 7.0

0.32 V 1.6 1.6 V 8.0

0.34 V 1.7 1.8 V 9.0

0.36 V 1.8 2.0 V 10.0

0.38 V 1.9 2.2 V 11.0

0.40 V 2.0 2.4 V 12.0

0.42 V 2.1 2.6 V 13.0

0.44 V 2.2 2.8 V 14.0

0.46 V 2.3 3.0 V 15.0

0.48 V 2.4 3.2 V 16.0

0.50 V 2.5 3.4 V 17.0

0.52 V 2.6 3.6 V 18.0

0.54 V 2.7 3.8 V 19.0

0.56 V 2.8 4.0 V 20.0

Move the jumper on the lower bank (J6) from its resting position (P1) to P4. This is
the system configuration position. Next, select the jumper position on upper bank J7
to achieve the desired function. Reference the table on page 20 for appropriate
jumper position locations.

Once the desired jumper position has been achieved, use the UP or DOWN push­buttons to make changes. Once the desired time delays have been set, move jumper
back to resting position (P1) of the upper bank (J7). If additional time delays are
desired, move the jumper to the appropriate position and once again use the push­buttons to set desired voltage to achieve desired time delay.

24 5909-9000 Rev 1

TIME DELAY

IN MINUTES

VOLT READING

AT TEST POINTS

TIME DELAY

IN MINUTES

GDC-350 Operation Manual

Once all desired time delay settings have been achieved, move the jumper back to
position 1 (P1) on jumper J7 and move the jumper back to position 1 (P1) on lower
the lower bank (J6). At that point, all new settings will be written to the EEPROM.

FUNCTION J6 J7

Low alarm “ON” time delay P4 P2

Low alarm “OFF” time delay P4 P3

High alarm “ON” time delay P4 P4

Audible alarm “ON time delay P4 P5

4.7. Temperature Display – Unit of Measure

The GDC-350 systems all have an on-board temperature chip from which information
is used to temperature compensate certain sensors. This temperature chip can also
be used as a second sensor in applications where the user requires both a gas
measurement and a temperature measurement. To switch between Celsius and
Fahrenheit displayed values, follow this procedure.

Move the jumper from the resting position (P1) on the lower bank (J6) to P4 and the
jumper on J7 to P8. Pressing the UP push-button will display the temperature in
Celsius and the output between test points TP1 and TP2 is 4.0 V. If the DOWN push­button is pressed, the temperature is displayed in Fahrenheit and the output between
the test points is 0 V.

Once the desired unit of measure has been achieved, move the jumper back to P1 on
the lower bank (J6). At that point, all new settings will be written to the EEPROM.

NOTE: The temperature sensor is always considered channel 2
(remote).

4.8. Latching Relay Function

The GDC-350 relays can be configured as “latching” for some applications.

To achieve this, move the jumper from resting position (P1) on the lower bank jumper
set (J6) to P4. This is the system configuration position. Next, move the jumper to P9
on the upper bank (J7).

Pressing the UP push-button activates the latching function and the output between
test points TP1 and TP2 is 4 V. Pressing the DOWN push-button de-activates the
latching function and the output between test points TP1 and TP2 is 0 V.

Once the desired latching or non-latching function has been achieved, move the
jumper back to P1 on upper bank (J7) and move the jumper back to P1 on lower bank
(J6). At that point, all new settings will be written to the EEPROM.

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GDC-350 Operation Manual

4.9. LED Digital Display

The GDC-350 system allows for a
limited amount of customization of the
optional LED digital display using
jumpers J3, J4, and J5.

x The display can be switched

completely off.

x The display brightness level can

be adjusted to low or high for best
visibility in your application.

x The display can indicate the gas

type only with no numerical value
for some applications.

Figure 4-5. Jumpers J3, J4, and J5

FUNCTION JUMPER SETTING

Switch digital display ON J3 Bridge P2 and P3

Switch digital display OFF J3 Bridge P1 and P2

Low brightness level J4 Bridge P1 and P2

High brightness level J4 Bridge P2 and P3

Display only gas name (acronym) J5 Bridge P1 and P2

Display gas value and gas name J5 Bridge P2 and P3

NOTE: The factory default setting for detectors with an LED digital
display are:

1) Display is ON

2) Brightness level is Low

3) Display indicates gas type and gas value

NOTE: Typically the LED digital display shows the gas name for 1
second, then the gas value is shown for 2 seconds. The sequence is
the same for 1- or 2-channel systems.

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GDC-350 Operation Manual

5. CALIBRATION

NOTE: During any calibration procedure, if the instrument sounds with

repetitive beeps, the sensor is not settling within tolerance (1% for catalytic
and solid-state sensors, 20% for electrochemical sensors). Contact
Bacharach support for additional information.

5.1. Calibration Specifications

Gas: Calibration span gases should be at least ±5% accuracy and have a current date
stamp. Gas generators should have a current dated cell installed. Service personnel
should flow zero emissions air or 20.9% volume oxygen before attempting to null
adjust toxic gas sensors. In some cases N
Nitrogen is required to null (zero) oxygen (O

(nitrogen) can be substituted for zero air.

2

) and carbon dioxide (CO2) sensors.

2

Exception: If the service person is confident of air quality and is careful (do not exhale
in the direction of the oxygen sensor being serviced while span adjusting), oxygen in
the breathing environment can be used as a fairly accurate source of span gas
(20.9% volume). It is not recommended to use this procedure for span adjustments of
oxygen sensors.

Regulators and Flow: Calibration gases that are lighter than or the same weight as air
(CO, O

, etc.) should be flowed at 0.5 LPM. Gases heavier than air (NO2, etc.) should

2

be flowed between 0.5 and 1.0 LPM. Fixed flow regulators provide more accuracy.
Gases should be flowed over the sensor for at least 2.5 to 4.0 minutes. Carbon
Monoxide sensors settle out very quickly, but sensors for reactive gases (NH

, etc.)

3

will take longer to stabilize to the calibration gas. All cylinder regulators supplied by
Bacharach use a fixed flow orifice.

Adapters: The proper calibration adapter should be utilized to allow the gas to
properly diffuse around the sensor. They are available from Bacharach. A
humidification chamber must be utilized for all solid-state sensors except ammonia.
This is also available form Bacharach. (See table on page
information.)

34 for ordering

5.2. Frequency Recommendations

Sensor Types / Applications Calibration Frequency

Parking garage detectors Once every 12 months

OHS (Occupational Health and Safety) applications Once every 6 months

For the purposes of safety in OHS applications, sensors should be gas tested (e.g.,
bump tested) once every month to confirm response.

IMPORTANT: In applications where life safety is critical, equipment should
be calibrated quarterly or on a more frequent basis. Bacharach is not
responsible for setting safety practices and policies. Safe work procedures
including calibration policies are best determined by company policy,
industry standards, and local codes.

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GDC-350 Operation Manual

NOTE: It is recommended that a calibration label should be applied after
every calibration to confirm work performed and the date it was confirmed.
If a controller is involved, the alarm set points should be indicated on a label
on the front door of the enclosure.

Calibration is achieved at the GDC-350 controller if the sensor is on board. If the
sensor is remote (i.e., a GDC-150 analog transmitter) the calibration is achieved at
the transmitter using the procedure indicated in its operation manual.

Required Equipment:

x Volt meter
x Calibration kit
x Calibration gases.

Users can order the calibration kit, calibration accessories and/or gases from any
Bacharach authorized distributor.

5.3. Calculating the Span Gas Value

To achieve calibration the user must first tell the GDC-350 what concentration of span
he is going to flow over the sensor. Within the controller, this is a voltage setting. The
range of 0-4 VDC is equal to the full measurement range of the sensor. Prior to
attempting to calibrate, determine the voltage value required. Consult the table on
page 23 for standard voltages. If the value desired is not indicated, use the following
formula to calculate the voltage required.

Therefore, in this example, the required voltage setting to calibrate a 0-200 ppm
sensor with 100 ppm is 2.0 VDC.

NOTE: Values for

Calibration Span Gas and Sensor Range in the

above equations must have the same Engineering Units (e.g., PPM, %
of LEL, % vol, etc.).

28 5909-9000 Rev 1

GDC-350 Operation Manual

NOTE: When calibrating solid-state sensors for combustibles or
refrigerants, the span gas must be humidified.
humidification chamber is required. The humidification chamber sits in
line between the cylinder of span gas and the calibration adapter.
Remove the sponge inside the chamber and wet it under the tap.
Squeeze out the excess water so it is not dripping wet and place it back
inside the chamber. As gas flows through the chamber, it absorbs water
which acts to humidify it and the humidified span gas flows over the
sensor. (See table on page

34 for ordering information.)

5.4. Calibrating the On-Board Sensor

SETTING SPAN GAS VALUE

Step Setting Span Gas Value Procedure

1 Move the jumper on J6 to P2 and move the jumper on J7 to P2.

The use of a

2

The audible alarm beeps once for confirmation. The system is now
waiting for the user to set the desired span value.

3 Attach the volt meter leads to test points TP1 and TP2.

4

Using the UP or DOWN push-buttons, achieve the calculated voltage on
the volt meter.

5 Move the jumpers from J6 and J7 back to their P1 resting positions.

CALIBRATING THE NULL (ZERO)

Step Calibrating the Null (Zero) Procedure

1 Attach a regulator to a cylinder of zero air (or nitrogen).

Insert the calibration adapter into the sensor opening on the front of the

2

enclosure. Use a slight twisting motion as you gently push the calibration
adapter into the sensor opening. If the calibration adapter is hard to
insert, moisten the “O” ring seal slightly then try re-inserting it.

3 Open the regulator valve fully allowing zero air to flow over the sensor.

Move the jumper on J6 to P2 and move the jumper on J7 to P3. The

4

audible alarm beeps once for confirmation. The system is now starting
the zero calibration stabilization time (30 seconds).

5

If desired, attach the volt meter leads to test points TP1 and TP2. The
reading should be 0.0 VDC.

The instrument will beep twice when the calibration begins. Leave the

6

zero air flowing over the sensor until the GDC-350 beeps three times
indicating the procedure is finished (1 minute).

7

5909-9000 Rev 1 29

Move the jumpers from J6 and J7 back to their P1 resting positions and
remove the zero air (or nitrogen).

GDC-350 Operation Manual

CALIBRATING THE SPAN

Step Calibrating the Span Procedure

1 Attach a regulator to a cylinder of span gas.

Insert the calibration adapter into the sensor opening on the front of the

2

3 Open regulator valve fully and allow span gas to flow over sensor.

4

5

6

enclosure. Use a slight twisting motion as you gently push the calibration
adapter into the sensor opening. If the calibration adapter is hard to
insert, moisten the “O” ring seal slightly then try re-inserting it.

Move the jumper on J6 to P2 and move the jumper on J7 to P4. The
audible alarm beeps once for confirmation. The system is now starting
the span calibration stabilization time (30 seconds).

If desired, attach volt meter leads to test points TP1 and TP2. The
reading should start moving towards the voltage calculated for the span
gas value.

The instrument will beep twice when the calibration begins. Leave the
span gas flowing over the sensor until the GDC-350 beeps three times
indicating the procedure is finished (2 minutes).

7

5.5. Calibrating a Second On-Board Sensor

Move the jumpers from J6 and J7 back to their P1 resting positions and
remove the span gas.

Calibration of the second on-board sensor has only one difference from the first on­board sensor calibration. Move the jumper on J6 to P3 then follow the same
procedure as in the previous section (Calibrating the On-board Sensor).

5.6. Calibrating a Remote Solid-State Sensor

SETTING SPAN GAS VALUE

Step Setting the Span Gas Value Procedure

1 Move the jumper on J6 to P3 and move the jumper on J7 to P2.

2

The audible alarm beeps once for confirmation. The system is now
waiting for the user to set the desired span value.

3 Attach volt meter leads to test points TP1 and TP2.

4

Using the UP or DOWN push-buttons, achieve the calculated voltage on
the volt meter.

5 Move the jumpers from J6 and J7 back to their P1 resting positions.

30 5909-9000 Rev 1

GDC-350 Operation Manual

CALIBRATING THE NULL (ZERO)

Step Calibrating the Null (Zero) Procedure

1 Attach a regulator to a cylinder of zero air.

Attach the flow adapter and open the regulator valve fully to allow zero air

2

3

to flow over sensor. Use a slight twisting motion as you gently push the
calibration adapter into the sensor opening. If the calibration adapter is
hard to insert, moisten the “O” ring seal slightly then try re-inserting it.

Move the jumper on J6 to P3 and move jumper on J7 to P3. The audible
alarm beeps once for confirmation. The system is now starting the zero
calibration stabilization time (30 seconds).

4

If desired, attach volt meter leads to test points TP1 and TP2. The voltage
should be 0.0 VDC.

The instrument will beep twice when the calibration begins. Leave the

5

zero air flowing over the sensor until the GDC-350 beeps three times
indicating the procedure is finished (1 minute).

6

Move the jumpers from J6 and J7 back to their P1 resting positions and
remove the zero air (or nitrogen).

CALIBRATING THE SPAN

Step Calibrating the Span Procedure

1 Attach a regulator to a cylinder of span gas.

Insert the calibration adapter into the sensor opening on the front of the

2

enclosure. Use a slight twisting motion as you gently push the calibration
adapter into the sensor opening. If the calibration adapter is hard to insert,
moisten the “O” ring seal slightly then try re-inserting it.

3 Open regulator valve fully and allow span gas to flow over sensor.

Move the jumper on J6 to P2 and move the jumper on J7 to P4. The

4

audible alarm beeps once for confirmation. The system is now starting the
span calibration stabilization time (30 seconds).

5

If desired, attach volt meter leads to TP1 and TP2. The reading should
start moving towards the voltage calculated for the span gas value.

The instrument will beep twice when the calibration begins. Leave the

6

span gas flowing over the sensor until the GDC-350 beeps three times
indicating the procedure is finished (2 minutes).

7

Move the jumpers from J6 and J7 back to their P1 resting positions and
remove the span gas.

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GDC-350 Operation Manual

5.7. Calibrating 4-20 mA Signal for Incoming Analog Transmitter

To perform this function you will need an accurate current source able to generate

4.0 mA and 20.0 mA current signals, or a Bacharach GDC-150.

USING A CURRENT SOURCE TO CALIBRATE THE NULL (ZERO)

Step Using A Current Source to Calibrate the Null (Zero) Procedure

1

Connect the current source to pin 10 and ground to pin 11 on the wiring
terminal block.

2 Set the current source to 4.0 mA.

3 Move the jumper on J6 to P3 and the jumper on J7 to P3.

4

5

The instrument will beep once for confirmation. The system is now starting
the zero calibration stabilization time (30 seconds).

If desired, attach volt meter leads to test points TP1 and TP2. Monitor the
voltage.

The instrument will beep twice when the calibration begins. The

6

instrument beeps three times indicating the procedure is finished
(2 minutes).

7 Move the jumpers from J6 and J7 back to their P1 resting positions.

USING A CURRENT SOURCE TO CALIBRATE THE SPAN

Step Using a Current Source to Calibrate the Span Procedure

1

Connect current source to pin 10 and ground to pin 11 on the wiring
terminal block.

2 Set the current source to 20.0 mA.

3 Move the jumper on J6 to P3 and the jumper on J7 to P4.

4

5

The instrument will beep once for confirmation. The system is now starting
the span calibration stabilization time (30 seconds).

If desired, attach volt meter leads to test points TP1 and TP2. Monitor the
voltage.

The instrument will beep twice when the calibration begins. The

6

instrument beeps three times indicating the procedure is finished
(2 minutes).

7

Move the jumpers from J6 and J7 back to their P1 resting positions and
remove the current source.

32 5909-9000 Rev 1

GDC-350 Operation Manual

USING A BACHARACH GDC-150 TO CALIBRATE THE NULL (ZERO)

Step Using a Bacharach GDC-150 to Calibrate the Null (Zero) Procedure

At the GDC-150: For zero calibration on the GDC-150, move the jumper

1

to P2 and set the voltage at TP1 and TP2 for 0 VDC. If transmitter has
been calibrated, TP1 and TP2 should be reading 0 VDC.

2

3

4

At the GDC-350: Move the jumper from J6 to P3 and the jumper from J7
to P3.

The instrument will beep once for confirmation. The system is now
starting the zero calibration stabilization time (30 seconds).

If desired, attach volt meter leads to test points TP1 and TP2. Monitor
the voltage. It should start moving towards zero gas value 0 VDC.

The instrument will beep twice when the calibration begins. The

5

instrument beeps three times indicating the procedure is finished
(2 minutes).

6 Move the jumpers from J6 and J7 back to their P1 resting positions.

USING A BACHARACH GDC-150 TO CALIBRATE THE SPAN

Step Using a Bacharach GDC-150 to Calibrate the Span Procedure

1

2

At the GDC-150: With the transmitter still connected, move the jumper to
P2 and set voltage at TP1 and TP2 for 2.00 VDC.

At the GDC-350: Move jumper from J6 to P3 and the jumper from J7 to
P2. Using the UP and DOWN push-buttons, set the voltage to 2.00 VDC.

3 Now, move jumper J7 to P4.

4

5

The instrument will beep once for confirmation. The system is now
starting the span calibration stabilization time (30 seconds).

If desired, attach volt meter leads to test points TP1 and TP2. Monitor
the voltage.

The instrument will beep twice when the calibration begins. The

6

instrument beeps three times indicating the procedure is finished
(2 minutes).

7

6. SYSTEM MAINTENANCE

Move jumpers from J6 and J7 back to their P1 resting positions and
remove the transmitter.

The GDC-350 series system requires virtually no maintenance other than regular
calibration of the integral and/or remote sensors and ensuring that excess water or
dust is not somehow entering the enclosure and physically damaging the circuit board
or internal components.

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GDC-350 Operation Manual

7. COMMON ACCESSORIES, OPTIONS, AND REPLACEMENT PARTS

Part Number Description

5909-0001 LED digital display (must be selected when ordering)

5909-0002 Water/dust-tight enclosure (NEMA 4X)

5209-0004 Splash guard (NEMA 4X enclosures only)

5209-0006 Calibration adapter for all other sensors

5209-0016 Calibration adapter for catalytic sensors

5209-0017 Sample draw pump (24 VAC-powered)

5209-0018 Sample draw pump (24 VDC-powered)

5209-0021 Humidification Chamber (for calibration of solid-state sensors)

5909-0003 System guard (16 gauge galvanized metal)

5909-0004 Enclosed external transformer

  

World Headquarters

621 Hunt Valley Circle, New Kensington, Pennsylvania 15068

Phone: [phone] Toll Free: 1-800-736-4666 Fax: [phone]

Website: www.MyBacharach.com E-mail: [e-mail]

34 5909-9000 Rev 1