General Information
Section 1

1.1 Introduction

This manual contains the information you need to
install, operate and maintain your MR-050 Series
dehydrator. Please take the time to read this
manual before attempting to operate or service the unit.

1.2 Description

MR-050 Series dehydrators provide dry air for
pressurizing small (up to 10 cubic feet, or 280 I, in
volume) antenna and transmission line systems.
The dehydrators produce -40°F (-40°C) dewpoint
dry air at an output rate of 0.05 cubic feet per
minute up to a total of 200 cubic feet (5660 I).

The dehydrators consist of an electrically-driven
air compressor, a replaceable desiccant drying
assembly, an automatic transmission line pressure
sensing system and a low-pressure alarm output
housed in a rigid metal chassis. They are suitable
for 19" rack mounting, wall mounting or free-standing
applications. The front panel features a pressure
gauge, an indicating on/off switch, a resettable
circuit breaker and a dryer viewing window.
For easy serviceability, power connections, alarm
output connections and the drying assembly are
accessible from the front of the unit.

The drying assembly consists of two clear arcylic
tubes which contain the color-indicating desiccant.
The clear acrylic makes it easy to view the condition
of the desiccant and a removable endpiece
makes the desiccant easy to replace.

The MR-050 Series senses transmission line
pressures and automatically maintains specified
pressures. Two basic models differ in pressure
range:

  • Low pressure variant (designated MRL-052)
  • High pressure variant (designated MRH-052).

    The MRL-052 (low pressure) maintains transmission
    line pressures between 0.3 and 0.5 lb/in2 (2.0
    and 3.4 kPa). The MRH-052 (high pressure) maintains
    transmission line pressures between 1.0 and
    5.0 lb/in2 (6.3 kPa and 32 kPa).

    A standard LP (low pressure) alarm provides an
    open or closed "dry" contact in the event of a low
    pressure condition. The alarm for the MRL-052 is
    set at 0.1 lb/in2' the MRH-052 is set at 0.5 lb/in2.

    The dehyrdators have a single output. Use the
    DP-4-001 distribution panel, described below, for
    additional output channels.
    • Four-Output Distribution Panel, includes one
    3/8" compression fitting and one shut-off valve per
    output. The unit mounts in a standard 19" equipment
    rack or to the top of the MR-050 using
    supplied brackets................................Type DP-4-001

    1.3 Operation

    MR-050 series dehyrdators include a compressor,
    silica-gel desiccant, high and low-pressure switches,
    check valves, and a low-pressure alarm sensor.

    When system pressure falls to the preset low limit,
    the low-pressure sensor activates the compressor.
    Air is channeled through two series-connected
    cylindrical desiccant "tubes", where the moisture is
    absorbed. The air exits the drying chambers at
    -40°F (-40°C), or better, dewpoint. It is then
    channeled to the distribution panel, manifold, or monitor
    and to the air-dielectric transmission line.

    When system pressure reaches the preset high
    limit, the high-pressure sensor shuts off the
    compressor. A check valve prevents system dry air
    from retreating back through the compressor.

    If system pressure falls significantly below the
    low-pressure trigger point, the low-pressure alarm
    sensor will activate an alarm contact indicating a
    significant system leak or a dehyrdrator failure.

    1.4 Specifications

    MRL / H-052 Dehydrator
    Output Pressure, approx. Low: 0.30 to 0.50 lb/in2
    (2.0 - 3.4 kPa)
    High: 1.0 to 5.0 lb/in2
    (6.9 - 34 kPa)
    Output Capacity (Total, approx.) 3.0 ft3 (80 l/h) @0.50 lb/in2
    0.05 ft3m (1.5 l/m)
    Output Dew Point, better than -40°F (-40°C)
    Drying Capacity per Charge Approx. 200 ft3 (5664 l)
    @ 80%R.H., 20°C
    Operating Temperature Range 32° - 100°F (0° - 40°C)
    Low Pressure Alarm Set Point (approx.) Low: 0.10 lb/in2 (0.7 kPa)
    High: 0.5 lb/in2 (3.4 kPa)
    Electrical Input (depending on model) 120 V, 60 Hz, 170 W
    230 V, 50 Hz, 130 W
    12-72 Vdc, 15 W
    Output Connectors Single 3/8" Compression
    fitting with shutoff valve
    Dimensions 19" Rack, 4 RU Tall
    by 8.6" Deep (218 mm)
    DP-4-991 Distribution Panel
    Number of Output Ports Four, 3/8" tubing with
    compression fittings
    Shut-off Valves Four, 90° twist open/close
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