Harris ZX10, Technical Manual

Page: 54 / 198

2-10 888-2595-001 12/20/11

WARNING: Disconnect primary power prior to servicing.
Section 2 Installation
ZX Series
To avoid operational problems due to excessive temperature, the blower openings must
not be blocked. The transmitter
Outline Drawing provides an indication of the relative
location of the transmitter blowers and the necessary clearances to respect.
Air input is from the transmitter front with hot air exhaust at the rear of the amplifier.
When factory rack integration has been provided, the exhaust air exits through a vent at
the top of the rack. An optional intake plenum is available to permit connection to an
external ducted air system, if desired. Consult the
Outline Drawing for the location of
the rack intake and exhaust ports with the plenum installed.
When the transmitter components are mounted in pre-existing rack, care must be taken
not to overheat the other pieces of equipment already installed in the rack. The exhaust
from the ZX amplifier chassis will typically be 10
o
C to 20
o
C hotter than the ambient
air. In many cases, this may necessitate use of a vented rear rack door or removal of
rear rack door altogether. Additionally, sufficient rear clearance must be left behind the
ZX amplifier chassis exhaust ports, typically 15cm (6 in.) or greater.
In general, transmitter cooling systems fall into two categories:
An open system in which the heated transmitter exhaust passes through a dedicated duct
to the outside of the transmitter building. The transmitter may receive fresh outside air
directly through a separate intake duct or may receive ambient air from the transmitter
hall, with the transmitter hall being supplied make-up air from outside via a filtered
inlet vent. With an open system, it is imperative to correctly balance the input and
output air flow volumes, paying particular attention to the pressure drops in external
ducts and providing external blowers to overcome these losses and ensure correct air
flow. The ZX transmitter internal air system is designed to supply sufficient air at the
required static pressure to cool the transmitter only and all external duct losses must be
compensated for by external blowers (this includes the optional intake plenum). Outside
air containing salt or pollution must have those items removed by an adequate filtration
system, and any pressure drops caused by filtration must also be considered.
A closed system in which the transmitter exhausts and inputs air directly to and from the
transmitter room. The transmitter room is closed to outside air and makes use of air
conditioning units to remove the resulting heat buildup. This type of system is
recommended in geographic areas with especially salty, sulfuric, or otherwise polluted
air. With a closed system, it is imperative to correctly balance the heat load. That is, to
size and position the air conditioning units properly to handle the heat generated by the
transmitter, ancillary equipment, building lighting, and even solar radiation entering
through windows. In may also be desirable to oversize the air conditioning system to
include the heat dissipated by the station test load, when in operation.
Figures for both the transmitter heat load and air flow volume are provided in the
transmitter
Outline Drawing . Consult a professional heating and ventilation expert in
your area for help in designing the building cooling system.