Macurco RD-6 User manual

IMPORTANT: Keep these user instructions for reference.
Macurco™ RD-6/RD-12
Refrigerant Detector, Controller and Transducer
User Instructions

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Table of Contents
1General Safety Information........................................................................................................................................................4
1.1 List of warnings .................................................................................................................................................................4
2Use Instructions and Limitations................................................................................................................................................5
2.1 Use For ..............................................................................................................................................................................5
2.2 Do NOT use for ..................................................................................................................................................................5
2.3 Features.............................................................................................................................................................................5
2.4 Specifications ....................................................................................................................................................................6
2.4.1 6-Series Low Voltage.....................................................................................................................................................6
2.4.2 12-Series Line Voltage...................................................................................................................................................6
3Installation and Operating Instructions .....................................................................................................................................6
3.1 Location.............................................................................................................................................................................6
3.2 Installation.........................................................................................................................................................................7
3.2.1 6-Series Low Voltage.....................................................................................................................................................7
3.2.2 12-Series Line Voltage.................................................................................................................................................12
3.3 Terminal Connection .......................................................................................................................................................17
3.3.1 6-Series Low Voltage...................................................................................................................................................17
3.3.2 12-Series Line Voltage.................................................................................................................................................17
4Operations ...............................................................................................................................................................................18
4.1 Power up .........................................................................................................................................................................18
4.2 Display turned “On” ........................................................................................................................................................18
4.3 Display turned “Off”........................................................................................................................................................19
4.4 4-20mA Loop ...................................................................................................................................................................19
4.5 Default – Factory Settings ...............................................................................................................................................20
4.5.1 Selecting Default Configuration – “dEF” .....................................................................................................................20
4.5.2 Power-Up Test Setting – “PUt” ...................................................................................................................................21
4.5.3 Display Setting – “dSP” ...............................................................................................................................................21
4.5.4 Buzzer Setting – “bUZ”................................................................................................................................................21
4.5.5 Alarm Relay Setting – “ArS” ........................................................................................................................................21
4.5.6 Alarm Relay Configuration – “Arc”..............................................................................................................................21
4.5.7 Fan Relay Setting – “FrS”.............................................................................................................................................21
4.5.8 Fan Relay Delay Setting – “Frd” ..................................................................................................................................21
4.5.9 Fan Relay Minimum Runtime Setting – “Frr”..............................................................................................................22
4.5.10 Fan Relay Latching Setting – “FrL”..........................................................................................................................22
4.5.11 Trouble Fan Setting – “tFS” ....................................................................................................................................22
4.5.12 4-20mA Output setting – “420”..............................................................................................................................22
4.5.13 Calibration Period Settings – “CAL” ..............................................................................................................................22
5Troubleshooting.......................................................................................................................................................................23
5.1 On-Board Diagnostics......................................................................................................................................................23
5.1.1 4-20mA troubleshooting.............................................................................................................................................23
5.1.2 “t” Error Codes............................................................................................................................................................23
5.2 Sensor Poisons ................................................................................................................................................................24
5.3 End-of-Life Signal.............................................................................................................................................................24
6Maintenance ............................................................................................................................................................................24
6.1 Sensor Life Reset .............................................................................................................................................................24
6.2 Cleaning...........................................................................................................................................................................25
7Testing......................................................................................................................................................................................25
7.1 Operation Test.................................................................................................................................................................25

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7.2 Manual Operation Test ...................................................................................................................................................26
7.3 Calibration and Test Kits..................................................................................................................................................26
7.4 Gas Testing ......................................................................................................................................................................27
7.4.1 Assembling the Regulator, Hose, and Test hood ........................................................................................................27
7.4.2 Testing the Fan Relay ..................................................................................................................................................27
7.4.3 Testing the Alarm Relay ..............................................................................................................................................28
7.4.4 Testing the 4-20mA loop.............................................................................................................................................28
7.5 Field Calibration Procedure.............................................................................................................................................29
8Appendix A – Table of Figures..................................................................................................................................................30
9Macurco Gas Detection Product limited warranty ..................................................................................................................31
Technical Support Contact Information .........................................................................................................................................31
General Contact Information..........................................................................................................................................................31

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1General Safety Information
The following instructions are intended to serve as a general guideline for the use of the Macurco RD-6 and RD-12 refrigerant
detector. This manual will refer to these devices as RD-xx unless content is specific to the 6-series or 12-series model. This
manual is not to be considered all-inclusive, nor is it intended to replace the policy and procedures for each facility. If you have
any doubts about the applicability of the equipment to your situation, consult an industrial hygienist or call Technical Support at
1-844-325-3050.
1.1 List of warnings
WARNING
Each person using this equipment must read and understand the information in this user
manual before use. Use of this equipment by untrained or unqualified persons or use that is
not in accordance with this user manual, may adversely affect product performance.
Use only for monitoring the gas which the sensor and monitor is designed to detect. Failure to
do so may result in exposures to gases not detectable and cause serious injury or death. For
proper use, see supervisor or user manual, or contact Technical Support at 1-844-325-3050.
This equipment may not function effectively below 0°F or above 125°F (-18°C or above 52°C).
Using the detector outside of this temperature range may adversely affect product
performance.
This detector helps monitor for the presence and concentration level of a certain specified
airborne gas. Misuse may produce an inaccurate reading, which means that higher levels of the
gas being monitored may be present and could result in overexposure and cause serious injury
or death. For proper use, see supervisor or User manual, or contact Technical Support at 1-844-
325-3050.
High voltage terminals (120/240 VAC) are located within this detector, presenting a hazard to
service technicians. Only qualified technicians should open the detector case and service the
internal circuits. Ensure power is de-energized from the detector relays prior to servicing the
unit. Failure to do so may result in electrical shock.
Do not disassemble unit or attempt to repair or modify any component of this instrument. This
instrument contains no user serviceable parts, and substitution of components may impair
product performance.
Using a certified gas with a concentration other than the one listed for this detector when
conducting a calibration and calibration verification test (bump test) will produce inaccurate
readings. This means that higher levels of the gas being monitored may be present and could
result in overexposure. For proper use, see supervisor or User manual, or contact Technical
Support at 1-844-325-3050.
The following steps must be performed when conducting a calibration or calibration verification
test (bump test) to ensure proper performance of the monitor. Failure to do so may adversely
affect product performance.
•When performing a calibration or calibration verification test (bump test), only use
certified calibration gas at the required concentration level.
•Do not test with expired calibration gas.
•Do not cover or obstruct display or visual alarm cover.
•Ensure sensor inlets are unobstructed and are free of debris
Failure to follow instructions outlined in this user manual can result in sickness or death.

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2Use Instructions and Limitations
WARNING
Each person using this equipment must read and understand the information in this user manual
before use. Use of this equipment by untrained or unqualified persons or use that is not in
accordance with this user manual, may adversely affect product performance.
2.1 Use For
The Macurco RD-xx is a dual relay Refrigerant (REF) detector, controller, and transducer. The RD-xx has selectable 4-20 mA
output, buzzer and digital display options. The RD-xx has a long-life solid-state sensor (expected lifespan of 7+ years). The RD-xx
is a low-level meter capable of displaying from 0-1,000 ppm of refrigerant gas. It is an electronic detection system used to
measure the concentration of refrigerant gas and provide feedback and automatic exhaust fan control to help reduce
refrigerant gas concentrations in industrial refrigeration, cold storage, warehouses, hockey rinks or other commercial
applications. The RD-xx is capable of detecting several refrigerants including R-22, R-134A, R-404A, R-407C and R-410A. The RD-
xx is factory calibrated and 100% tested for proper operation.
Refrigerants are colorless and nearly odorless liquids or gases divided into two groups according to toxicity and flammability.
See ANSI/ASHRAE Standard 34-2007 - Designation and Safety Classification of Refrigerants for details. Always review the
refrigerant MSDS and safety classifications before use. RD-xx can be used stand alone, with the Macurco Detection and
Ventilation Control Panel, other 12 VAC or 24 VDC fire/security panels or building automation systems.
WARNING
Use only for monitoring the gas which the sensor and monitor is designed to detect. Failure to
do so may result in exposures to gases not detectable and cause serious injury or death. For
proper use, see supervisor or user manual, or contact Technical Support at 1-844-325-3050.
2.2 Do NOT use for
The RD-xx is not intended for use in hazardous locations. Do not mount the RD-xx where the normal ambient temperature is
below 0°F or exceeds 125°F (below -18°C or above 52°C). The RD-xx mounts on a 4x4 electrical box supplied by the contractor.
Do not install the RD-xx inside another box unless it has good air flow through it.
WARNING
This equipment may not function effectively below 0°F or above 125°F (-18°C or above 52°C).
Using the detector outside of this temperature range may adversely affect product performance.
2.3 Features
•ETL Listed to UL 61010-1 and CSA C22.2 No 61010-1
•Low level meter capable of displaying from 0-1,000 ppm refrigerant gas
•Selectable fan and alarm relay activation
•5 A SPDT fan relay controls starters of exhaust fans
•0.5 A N.O. or N.C. alarm relay connects to warning devices or control panels
•4-20 mA Current Loop
•RD-xx mounts on a standard 4x4 electrical box and becomes cover for the box
•Supervised system: any internal detector problem will cause the fan & alarm relay to activate
•Calibration kit is available. One screw allows access for calibration or gas test

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2.4 Specifications
•Shipping Weight: 1 pound (0.45 kg)
•Size: 4 1/2 x 4 x 2 1/8 in. (11.4 x 10.2 x 5.4 cm)
•Color: White or Dark grey
•Connections: plugs/terminals
•Mounting box: (not included) 4x4 electric
•Fan relay: 5 A, 240 VAC, pilot duty, SPDT, latching or non-latching
•Fan relay actuation: selectable at diS (disable), 100,150, 200, 250, 300 (default), 350ppm
•Fan Delay Settings of 0, 1, 3 (default), 5 and 10 minutes
•Fan Relay Minimum Runtime settings are 0 (default), 3, 5, 10 or 15 minutes
•Fan relay latching or not latching (default) selectable
•Alarm relay: 0.5A 120 V, 60 VA
•Alarm relay actuation: selectable N.O. (default) or N.C.
•Alarm relay settings: diS, 100, 150, 200, 250, 300 350, 400, 450, 500, 550 or 600ppm (default)
•Current Loop: 4-20 mA for 0-1,000 ppm refrigerant gas, selectable to ’bAS’ (default), ‘EnH’, OFF
•Buzzer: 85 dBA at 10cm settable to on (default) or off
•Digital display: 3-digit LED selectable to on (default) or off
•Operating environ: 0°F to 125°F (-18°C to 52°C).10 to 90% RH non-condensing
2.4.1 6-Series Low Voltage
•Power: 3 W (max) from 12 to 24 VAC or 12 to 32 VDC
•Current @ 24 VDC: 75 mA in alarm (two relays), 50 mA (fan relay only) and 23 mA stand by
2.4.2 12-Series Line Voltage
•Power: 100-240VAC (50 TO 60 HZ)
•Current 1.0 A MAX
3Installation and Operating Instructions
The following instructions are intended to serve as a guideline for the use of the Macurco RD-xx Refrigerant Detector. It is not to
be considered all-inclusive, nor is it intended to replace the policy and procedures for each facility. If you have any doubts about
the applicability of the equipment to your situation, consult an industrial hygienist or call Technical Support at 844-325-3050.
WARNING
This detector helps monitor for the presence and concentration level of a certain specified
airborne gas. Misuse may produce an inaccurate reading, which means that higher levels of the
gas being monitored may be present and could result in overexposure and cause serious injury
or death. For proper use, see supervisor or User manual, or contact Technical Support at 1-844-
325-3050.
3.1 Location
A RD-xx is normally mounted low in the room on a wall or column one foot above the floor in a central area where air
movement is generally good. Use the same spacing as for smoke detectors, 30-foot centers, 900 square feet per detector (84 sq.
meters). The coverage depends on air movement within the room or facility. Extra detectors may be needed near any areas
where people work or where the air is stagnant. The RD-xx mounts on a 4x4 electrical box supplied by the contractor. Do not
install the RD-XX inside another box unless it has good air flow through it. Do NOT mount the RD-xx where the normal ambient
temperature is below 0°F or exceeds 125°F (below -18°C or above 52°C).

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WARNING
High voltage terminals (120/240 VAC) are located within this detector, presenting a hazard to
service technicians. Only qualified technicians should open the detector case and service the
internal circuits. Ensure power is de-energized from the detector relays prior to servicing the
unit. Failure to do so may result in electrical shock.
3.2 Installation
3.2.1 6-Series Low Voltage
1. The RD-6 mounts on a 4” square (or 4x4) electrical box supplied by the contractor. Do not mount the RD-6 inside
another box, unless it has good air flow through it.
2. Connect the RD-6 to Class 2 power supply only. It is suggested to use a separate transformer for powering the unit or
units because of possible interferences from other devices on the same power supply.
3. Connect the RD-6 to the control cables with terminal plugs. When making connections, make sure the power is off.
4. There are two terminals for Power: 12 to 24 VAC or 12 to 32 VDC, with no polarity preference.
5. There are two terminals for the dry alarm relay contacts, again with no polarity preference. The alarm relay can switch
up to 0.5 A 120 V, or 60 VA. The alarm relay is activated if gas reaches or exceeds the alarm settings. See OPERATION
section of these User Instructions for details on relay settings.
6. The alarm relay can be configured to normally open (default) (N.O.) or normally closed (N.C.) and will activate if the gas
concentration exceeds alarm set point. It will deactivate once the gas concentration drops below the alarm set point.
Note that the “disable” setting will cause the alarm relay not to engage at all.
7. The dry contact, SPDT fan relay has three terminals. The common (COM.), normally open (N.O.) and the normally
closed (N.C.) contact. The fan relay can switch up to 5.0 A up to 240 VAC. See OPERATION section of these User
Instructions for details on relay settings.
8. The Fan Relay can be configured for latching or non-latching (default) when activated (when the gas concentration
exceeds fan relay setpoint). Once latched in, power will need to be interrupted or the “TEST” button pressed to un-
latch the relay condition.
9. The Fan Relay will engage if the fan setting refrigerant concentration is exceeded for longer than the Fan Relay Delay
time. Unless it is configured for latching, the fan relay will disengage once both of these conditions have been met:
•Refrigerant gas concentration has dropped below fan setting
•Fan Relay Runtime has been exceeded
Note that the “disable” fan setting will cause the fan relay to not engage. The fan relay will engage in trouble fault condition
(if the Trouble Fan Setting Option is set to “On”) and will disengage once trouble fault condition is cleared.
10. The Current Loop is 4 mA in clean air and 20 mA for 1,000 ppm refrigerant gas

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Figure 3-1 6-Series 4-20mA Output Diagram
Figure 3-2 6-Series Rear View

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Figure 3-3 6-Series Garage Diagram
Figure 3-4 6-Series Multiple Device Diagram
1. One sensor per 900 square feet (approximately)
2. Mount the RD-6 about one foot above the floor.
3. See application building code for fan size and air changes per period of time.
4. Make sure that there are air inlets to provide adequate airflow throughout the building.
5. The RD-xx fan relays are dry contact and can switch up to 240V (see section 2.4 Specifications)
6. Several fan relays (starters) may be used. Match the relays to the fan specifications.

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Figure 3-5 6-Series Alarm Control Panel Diagram
1. The RD-6 can be used with 12VDC or 24 VDC fire panels.
2. Alarm panel provides battery backup power to the RD-6.
3. The RD-6 dry contact relay can use panel power or fan power (See Ratings).
4. Match fan relay contacts to fan size and coil voltage to a power source.
5. Alarm control panels are available with many features and can control other devices such as smoke detectors, fire
detectors, and burglar alarms.

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Figure 3-6 6-Series DVP-120 Control Panel Diagram
Gas detection and exhaust fan control are provided by the Macurco DVP-120 system. This system will use Macurco gas
transducers. Each transducer will measure the level of the target gas and provide this information to the DVP-120 over a 4-
20mA current loop. The transducers operate on low voltage (24VDC). All power and signal connections for the transducers are
provided from the DVP-120 control panel via unshielded four conductor cable. The DVP-120 control panel provides three relays
which can be used for ventilation, fan control, or alarm signaling. These relays (SPDT-Form C) are for pilot duty only, capable of
switching 10 amps loads up to 240VAC.
Note: Transducer power connections are non-polarized.
Figure 3-7 6-Series Alternate Alarm Panel
In this application (above) the Fan or primary relay is used as a low-level alarm relay. The Alarm or secondary relay is used as a
supervisory relay when utilized in the normally closed configuration. The RD-6 monitors all critical functions of the unit through
software diagnostics that continually test and verify its operations. If a problem is found, the unit will switch to a fail-safe/error
mode or trouble condition. In this error mode, the Fan* and Alarm relays will be activated indicating the trouble condition at the
panel and the RD-6 display will flash the error. *See the Trouble Fan Setting Option.

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Figure 3-8 6-Series Horn & Strobe Combo Wiring
3.2.2 12-Series Line Voltage
1. The RD-12 mounts on a 4” square (or 4x4) electrical box supplied by the contractor. Do not mount the RD-12 inside
another box, unless it has good air flow through it.
2. There are two terminals for the dry alarm relay contacts, again with no polarity preference. The alarm relay can switch
up to 0.5 A 120 V, or 60 VA. The alarm relay is activated if gas reaches or exceeds the alarm settings. See OPERATION
section of these User Instructions for details on relay settings.
3. The alarm relay can be configured to normally open (default) (N.O.) or normally closed (N.C.) and will activate if the gas
concentration exceeds alarm set point. It will deactivate once the gas concentration drops below the alarm set point.
Note that the “disable” setting will cause the alarm relay not to engage at all.
4. The dry contact, SPDT fan relay has three terminals. The common (COM.), normally open (N.O.) and the normally
closed (N.C.) contact. The fan relay can switch up to 5.0 A up to 240 VAC. See OPERATION section of these User
Instructions for details on relay settings.
5. The Fan Relay can be configured for latching or non-latching (default) when activated (when the gas concentration
exceeds fan relay set point). Once latched in, power will need to be interrupted or the “TEST” button pressed to un-
latch the relay condition.
6. The Fan Relay will engage if the fan setting refrigerant gas concentration is exceeded for longer than the Fan Relay
Delay time. Unless it is configured for latching, the fan relay will disengage once both of these conditions have been
met:
•Refrigerant gas concentration has dropped below fan setting
•Fan Relay Run time has been exceeded
Note that the “disable” fan setting will cause the fan relay to not engage. The fan relay will engage in trouble fault
condition (if the Trouble Fan Setting Option is set to “ON”) and will disengage once trouble fault condition is cleared.
The Current Loop is 4 mA in clean air and 4-20 mA for 0-1,000 ppm refrigerant gas

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Figure 3-9 12-Series 4-20mA Output Diagram
Figure 3-10 12-Series Rear View

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Figure 3-11 12-Series Stand Alone Layout
Figure 3-12 12-Series Multiple Device Diagram

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Figure 3-13 12-Series Alarm Control Panel Diagram
Figure 3-14 12-Series DVP-120 Control Panel Diagram

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Figure 3-15 12-Series Alternate Alarm Panel
In this application (above) the Fan or primary relay is used as a low-level alarm relay. The Alarm or secondary relay is used as a
supervisory relay when utilized in the normally closed configuration. The RD-12 monitors all critical functions of the unit
through software diagnostics that continually test and verify its operations. If a problem is found, the unit will switch to a fail-
safe/error mode or trouble condition. In this error mode the Fan* and Alarm relays will be activated indicating the trouble
condition at panel and the RD-12 display will flash the error. *See the Trouble Fan Setting Option.
Figure 3-16 12-Series Horn & Strobe Combo Wiring

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3.3 Terminal Connection
3.3.1 6-Series Low Voltage
With the exception of the safety ground, all field wiring is completed via modular connectors (provided). After wiring, simply
plug the modular connectors into the matching connectors on the back side of the detector.
NOTE: 22 to 12 AWG wire shall be used. Wire used shall meet the temperature range of the detector i.e. 0°F to 125° F (-18°C to
52°C).
3.3.1.1 Mains Power Connection
Connect the RD-6 to Class 2 power supply only. It is suggested to use a separate transformer for powering the unit or units
because of possible interferences from other devices on the same power supply. Connect the RD-6 to the control cables with
terminal plugs. When making connections, make sure the power is off. There are two terminals for Power: 12 to 24 VAC or 12 to
32 VDC, with no polarity preference
Ensure that the wire cannot be easily pulled from the connector. Plug the modular connection into the Fan/Power connection
and ensure that it latches into the header properly.
3.3.1.2 Fan Relay Connection
All of the SPDT Fan relay terminals are available at the Fan/Power modular connector. Each Fan relay terminal normally open,
common and normally closed (NO, COM and NC) can accommodate a wire size 12 to 24 AWG. To install the wiring for the relays,
disconnect the connector from the header. Strip the insulation of each wire back approximately 1/4 in. (6.5 mm), insert the bare
wire into the terminal and tighten the screw clamp. Ensure that the wire cannot easily be pulled from the connector. Plug the
modular connection into the Fan/Power connection and ensure that it latches into the header properly.
3.3.1.3 Alarm Relay Connection
The external alarm connections (A and B) are available at the Alarm modular connector. There is no polarity for these
connections. To install the wiring for the alarm contacts, disconnect the connector from the header on the detector. Strip the
insulation of each wire back approximately 1/4 in. (6.5 mm), insert the bare wire into the terminal and tighten the screw clamp.
Ensure that the wire cannot easily be pulled from the connector. When the wires are connected seat the modular connector
into the header ensuring that the latch engages
3.3.1.4 4-20mA Signal Connection
The positive and negative 4-20mA signal connections (+ and -) are available at the 4-20mA modular connector, a 2-position
connector. To install the wiring for the 4-20 mA contacts, disconnect the connector from the header on the detector. Strip the
insulation of each wire back approximately 1/4 in. (6.5 mm), insert the bare wire into the terminal and tighten the screw clamp.
Ensure that the wire cannot easily be pulled from the connector. When the wires are connected seat the modular connector
into the header ensuring that the latch engages
3.3.2 12-Series Line Voltage
With the exception of the safety ground, all field wiring is completed via modular connectors (provided). After wiring, simply
plug the modular connectors into the matching connectors on the back side of the detector.
3.3.2.1 Mains Power Connection
Mains connections should be done in accordance with National and Local Electrical Codes. Only qualified personnel should
connect Mains power to any device. Macurco recommends a minimum wire size of AWG18 and the wire insulator must be rated
for 140°F (60°C) service. The modular connector will accept wire from 12 to 22 AWG.
The safety ground wire should be secured to the ground screw of the metal electrical box. Tighten the screw and make sure the
wire is snug. Ensure that the wire cannot be pulled out from under the screw.

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The Line (L) and Neutral (N) wires should be stripped 1/4 in. (6.5 mm), insert the wire into the ”L” and “N” wire positions of the
modular Fan/Power connector and tighten the screw clamp. Ensure that the wire cannot be easily pulled from the connector.
Plug the modular connection into the Fan/Power connection and ensure that it latches into the header properly.
3.3.2.2 Fan Relay Connection
All of the SPDT Fan relay terminals are available at the Fan/Power modular connector. Each Fan relay terminal normally open,
common and normally closed (NO, COM and NC) can accommodate a wire size 12 to 24 AWG. To install the wiring for the relays,
disconnect the connector from the header. Strip the insulation of each wire back approximately 1/4 in. (6.5 mm), insert the bare
wire into the terminal and tighten the screw clamp. Ensure that the wire cannot easily be pulled from the connector. Plug the
modular connection into the Fan/Power connection and ensure that it latches into the header properly.
3.3.2.3 Alarm Relay Connection
The external alarm connections (A and B) are available at the Alarm modular connector. There is no polarity for these
connections. To install the wiring for the alarm contacts, disconnect the connector from the header on the detector. Strip the
insulation of each wire back approximately 1/4 in. (6.5 mm), insert the bare wire into the terminal and tighten the screw clamp.
Ensure that the wire cannot easily be pulled from the connector. When the wires are connected seat the modular connector
into the header ensuring that the latch engages
3.3.2.4 4-20mA Signal Connection
The positive and negative 4-20mA signal connections (+ and -) are available at the 4-20mA modular connector, a 2-position
connector. To install the wiring for the 4-20 mA contacts, disconnect the connector from the header on the detector. Strip the
insulation of each wire back approximately 1/4 in. (6.5 mm), insert the bare wire into the terminal and tighten the screw clamp.
Ensure that the wire cannot easily be pulled from the connector. When the wires are connected seat the modular connector
into the header ensuring that the latch engages.
Note: The 4-20mA current loop outputs may be used with the Macurco DVP-120 control panel or other systems. The 4-20mA
signal connections to detectors should be size AWG18 (minimum) for short runs. Refer to the table for recommended wire
gauges. Do not bundle detector 4-20mA signal connections with AC power cables to prevent electrical interference. If AC power
connections must be bundled with the detector 4-20mA signal cables, the signal connections should be made with twisted pair
of the appropriate gauge, with an overall foil and braid shield. All shields should be terminated at the DVP-120 end of the cable
only. A ground stud is provided near the bottom left corner of the DVP-120 panel.
4Operations
4.1 Power up
The RD-xx steps through an internal self-test cycle for the first minute that it is powered. The unit will execute the test cycle any
time power is dropped and reapplied (i.e. power failure). During the self-test cycle, the unit will display the firmware version
number, then count down from 150 to 0 (if the display option is “on”) and finally go into normal operation. The alarm relay will
be activated for 10 seconds and the fan relay for 150 seconds during the power-up cycle unless the “Power Up Test” (PUt)
option is OFF. The indicator light (LED) will flash green during the self-test cycle. At the end of the 2 ½ minute cycle, the unit will
take its first sample of the air and the indicator light will turn solid green.
4.2 Display turned “On”
Clean Air – With the display function turned “On”, the RD-xx will show the current concentration of refrigerant ppm or “0”
(zero) in clean air.
Fan level – When the refrigerant concentration reaches the Fan Relay setting (100 ppm, for example) the display will flash back
and forth between “FAn” and “current gas reading.

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Alarm level – With the display function turned “On” and the refrigerant concentration reaching the Alarm Relay setting, (600
ppm, for example) the display will flash back and forth between “ALr” and current gas reading. The buzzer will sound indicating
“Alarm” if the buzzer is turned “On”.
Trouble – With the display function turned “On” and the device is in a trouble state, the display will display the “t” Error code
(t01 for example). If the Trouble Fan Setting is enabled, the Fan relay will switch activating the relay. See Section 5.1.2 “t” Error
Codes and Section 4.5.11 Trouble Fan Setting – “tFS”.
Calibration Due- With Calibration Period functionality enabled, if a detector is within 1 month of calibration period, then display
will flash back and forth between “dUE” and current gas reading. Calibration Due is resolved only with successful field
calibration.
4.3 Display turned “Off”
Clean Air – With the display function turned” Off”, the display does not show the refrigerant concentration. Only the Power
indicator light on will be on.
Fan Level – When the refrigerant concentration reaches the Fan Relay setting (100ppm, for example) the display will show
“FAn” continuously as long as the fan relay is enabled.
Alarm Level – With the display function turned off the display does not show the refrigerant concentration but will show “ALr”
when the Alarm relay is activated.
Trouble – With the display function turned “On” and the device is in a trouble state, the display will display the “t” Error code
(t01 for example). If the Trouble Fan Setting is enabled, the Fan relay will switch activating the relay. See Section 5.1.2 “t” Error
Codes and Section 4.5.11 Trouble Fan Setting – “tFS”.
Calibration Due- With Calibration Period functionality enabled, if a detector is within 1 month of calibration period, then display
will show “dUE” continuously. Calibration Due is resolved only with successful field calibration.
4.4 4-20mA Loop
4-20mA settings selected to ‘bAS’ or ‘EnH’ is considered as 4-20mA function turned ON.
Clean Air – With the 4-20 mA function turned “On” and the current gas concentration at “0 ppm” (zero), the 4-20mA loop will
output 4 mA.
Gas read – With the 4-20 mA function turned “On” the output will read between 4 mA and 20 mA depending on the current
concentration of target gas.
Trouble – With the 4-20 mA function turned “On” and Trouble Fan Setting enabled. The 4-20mA loop will output 1 mA or 24 mA
depending on the Trouble condition. See Section 5.1 On-Board Diagnostics.

Macurco RD-xx User Manual
REV – 1.0 [34-2900-0511-7 ] 20 |Page
4.5 Default – Factory Settings
Setting:
Default:
Power Up Test
On
Display
On
Buzzer
On
Alarm Relay Setting
600 ppm
Alarm Relay Configuration
Normally Open (NO)
Fan Relay Setting
300 ppm
Fan Relay Delay
3 minutes
Fan Relay Minimum Runtime
0 minutes
Fan Relay Latching
Off
Trouble Fan Setting
Off
4-20mA
bAS
Calibration Period
diS (disabled)
To change settings, remove the Philips screw on the front of the RD-xx. Pull off the front cover of the unit.
Figure 3-17 Board View
4.5.1 Selecting Default Configuration – “dEF”
To select the Default Configuration, in normal mode, push the Next button to get to “Con” or the Configuration menu. Then
push the Enter button to enter the Con menu. The first selection is the “dEF” or Default setting. Push Enter. If it is already in
Default configuration, there will be no action. If it is not already in Default configuration, “nO” will be displayed. Push Next to
change it to “yES” (flashing) then push Enter to confirm the change (solid) and push Enter again to return to “dEF” in the con
menu. Push Next until “End” is displayed then push Enter to get back to normal operation.
Note: “dEF” menu cannot be changed during calibration due warning and calibration overdue trouble. Refer to Section 4.5.13
Calibration Period Settings – “CAL” for Calibration Due Warning and Calibration Overdue trouble.