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Wilhelmsen Ships MRD 4 S Installation And Operation Manual

Marine refrigerant gas leak monitor
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MRD – 4/6 S
Marine Refrigerant Gas Leak Monitor
Installation and Operation Manual

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Summary of Contents for Wilhelmsen Ships MRD 4 S

  • Page 1 MRD – 4/6 S Marine Refrigerant Gas Leak Monitor Installation and Operation Manual...

  • Page 2: Table Of Contents

    MRD – 4/6 S Manual Table of Contents SECTION 1. OVERVIEW ................3 1.1. General Information ................3 1.2. Technical Specifications ................6 SECTION 2. PLACING SENSORS ..............9 2.1. Installation Warnings ................9 2.2. General Guidelines .................. 9 SECTION 3. HOUSING DIMENSIONS ............

  • Page 3: Overview

    MRD – 4/6 S Manual Section 1. Overview 1.1. General Information The MRD is the ideal gas detection solution for installations requiring a quality and affordable stand-alone gas detector. It consists of 1 to 6 remote gas sensors connected to and powered by a controller. The controller provides visual, audible, and relay alarms on the detection of gases.
  • Page 4 MRD – 4/6 S Manual Figure 1. MRD 4- and 6-Channel Controller PCB (Dual Level Alarm)
  • Page 5 MRD – 4/6 S Manual Figure 2. Examples MRD PCBs...

  • Page 6: Technical Specifications

    MRD – 4/6 S Manual 1.2. Technical Specifications Specification Description Power Supply 100 - 230 VAC 50 - 60 Hz, or 12 VDC (specified at time of order) Alarm Silence Key Switch Alarm Delay Preset: 25 sec (low), 30 sec (high) Power Green Monitoring LED...
  • Page 7 MRD – 4/6 S Manual Specification Description 4- and 6-channel systems Std. Enclosure MRD: IP41 Ratings Controller: IP51 10.3” x 10.4” x 303” Dimensions and Weight: 262 x 265 x 84 mm Controller 5.1 lbs / 2.3 kg Sensor Type/Enclosure Dimensions Weights Dimensions...
  • Page 8 MRD – 4/6 S Manual Supported CFM and Duct Sizes for the Duct Mount Housing Units Duct Size Inches 12 x 12 12 x 24 18 x 18 24 x 24 24 round Feet 1 x 1 1 x 2 1.5 x 1.5 2 x 2 Pi x 1 x 1...

  • Page 9: Placing Sensors

    MRD – 4/6 S Manual Section 2. Placing Sensors 2.1. Installation Warnings NOTE: This instrument can be equipped with a semiconductor sensor for the detection of refrigerant, combustible and VOC gases. Semiconductor sensors are not gas specific and respond to a variety of other gases including propane exhaust, cleaners, and solvents.
  • Page 10 MRD – 4/6 S Manual moisture is present unless an appropriate enclosure is used. Avoid routing sensor cabling outside of premises, or between buildings via overhead cables. Also, sensor wiring should be kept to a minimum of 20 in (500mm) from the main power supply and telephone cables. When connecting the main power supply and/or sensor cables ensure a second mechanical fixing is used.

  • Page 11: Housing Dimensions

    MRD – 4/6 S Manual Section 3. Housing Dimensions Figure 3. MRD Standard Housing...
  • Page 12 MRD – 4/6 S Manual Figure 4. MRD Exd Housing Figure 5. MRD IP66 Housing (with Splash Guard)
  • Page 13 MRD – 4/6 S Manual Figure 6. MRD IP66 Housing with Remote Sensor See Figure 5 for mounting locations Cut out in duct for pitot 22mm Figure 7. MRD IP66 Housing with Airflow Duct Mount...
  • Page 14 MRD – 4/6 S Manual Figure 8. 4- and 6-Sensor Controller Housing...

  • Page 15: Wiring Instructions

    MRD – 4/6 S Manual Section 4. Wiring Instructions 4.1. Wiring MRDs Step Wiring MRDs Connect a 4-conductor cable (18 AWG recommended) to a terminal block on the MRD controller (CN1, CN2, etc). Route the cable to an MRD. For standard (IP41) MRD housings, remove the lid by: ...

  • Page 16: External Audible Alarm

    MRD – 4/6 S Manual Max 8.8Ω/wire Resistance: NOTE: You may use different cables and longer distances provided the corresponding resistance shown above is not exceeded. 4.2. External Audible Alarm NOTE: This section applies to the external audible alarm (4-6 channel systems only).

  • Page 17: Relays

    MRD – 4/6 S Manual Step Wiring the DC Output The return from the device is connected to "-" on the 12V terminal. 4.4. Relays All relay outputs are labeled HIGH, LOW and FAULT on the silkscreen. Connect leads to terminal block for Common (COM) and N/O and/or N/C connections as required.
  • Page 18 MRD – 4/6 S Manual NOTE: The blanking plugs for cable entries should only be removed if being replaced by conduit fittings. NOTE: If replacement of either main power fuse is required, use only a 2A 250V slow fuse (0.79 in/20mm) T2AL250V. Figure 9.

  • Page 19: Operation And Stabilization

    MRD – 4/6 S Manual Section 5. Operation and Stabilization When power to the unit is switched on, the green LED is illuminated, and then there is a 3-minute delay before the system activates. This allows the sensors to warm up to the correct temperature for gas detection. When a unit has been off or stored for a long time the stabilizing period may be longer than 3 minutes.
  • Page 20 MRD – 4/6 S Manual Operation Description State Idle Only the green light on the panel is on. No gas is present. Power If the green light is off, power to the unit has been Interrupted interrupted. Refer to Section 7. Alarm Two-alarm Units: Conditions...

  • Page 21: Functional Tests And Calibration

    MRD – 4/6 S Manual Section 6. Functional Tests and Calibration 6.1. Introduction To comply with the requirements of EN378 and the European F-GAS regulation, sensors must be tested annually. However, local regulations may specify the nature and frequency of this test. CAUTION: Check local regulations on calibration or testing requirements.
  • Page 22 MRD – 4/6 S Manual IMPORTANT: Before testing the sensors on-site, the MRD must have been powered up and allowed to stabilize for at least 24 hours. See Section 5. IMPORTANT: Failure to test or calibrate the unit in accordance with applicable instructions and with industry guidelines may result in serious injury or death.

  • Page 23: Electrical Reset

    MRD – 4/6 S Manual adjusting all the outputs, to ensure that they are activated at the specified gas concentration. CAUTION: Before you carry out the bump test or calibration:  Advise occupants, plant operators, and supervisors.  Check if the MRD is connected to external systems such as sprinkler systems, plant shut down, external sirens and beacons, ventilation, etc.

  • Page 24: On-Site Gas Calibration

    MRD – 4/6 S Manual Step Electrical Reset For high-level alarm voltage, connect your DC voltmeter between TP5 (0V) and TP1 (+V) as shown in Figure 9 Adjust pot P7. 6.3. On-Site Gas Calibration This section and the next cover calibration using calibration gas cylinders.
  • Page 25 MRD – 4/6 S Manual Step Adjusting the Low Alarm Threshold Voltage (ATV) Adjust P8 to the new value. Record and use the new value for subsequent electrical set-ups. Step Adjusting the High Alarm Threshold Voltage (ATV) Monitor voltage between TP5 (0V) & TP4 (+Ve)/0V and VS on IR units.

  • Page 26: Troubleshooting

    MRD – 4/6 S Manual Section 7. Troubleshooting Symptom Possible Cause(s)  Power failure (check supply) No lights displayed  Tripped circuit breaker or blown fuse on on panel electrical supply  Blown fuse at the electrical supply on the controller PCB board ...
  • Page 27 MRD – 4/6 S Manual The terminals should have the values shown in the table below. You can monitor this as follows:  Connect voltmeter and monitor voltage between TP5 (0V) and TP4 (+Ve). For IR, monitor between 0V and VS. Table 1.
  • Page 28 MRD – 4/6 S Manual This page is intentionally blank.

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