Operating instructions

5
SAFETY
At times be aware of overhead obstructions especially power lines (we recommend
use of the Sigalarm, high voltage power line proximity warning system. Please call
for further details). Note that in the interest of safety and reducing mast wear, the
Sigalarm and air supply system must be arranged so as to dump air from the mast in
the event of triggering the Sigalarm or any similar device. With vehicle mounted
installations where a retracted mast projects above the roofline, always fix a notice in
the driving cab advising the driver of the overall height. Where a mast is vehicle or
trailer mounted DO NOT MOVE THE VEHICLE OR TRAILER WITH THE MAST
EXTENDED (see also Magnetic Switch page 14).
When erecting a mast, watch particularly for snagging guys and cables.
Due to the low pressures needed to extend masts, under no circumstances should
standard commercially available compressors be used without consultation with the
supplier/manufacturer.
Mast Air pressure
NH/NK series 1.75kg/cm maximum – 1.20kg/cm minimum (25-17 psi)
NL/NX series 1.40kg/cm maximum – 1.12kg/cm minimum (20-16 psi)
NY series 1.12kg/cm maximum – 0.98kg/cm minimum (16-14 psi)
Air pressure should not be increased above that stipulated without first referring to
the supplier/manufacturer. Over pressurisation severely strains the collar and base
section screws and can, in extreme circumstances, force a collar off and allow the
tube to blow out.
If a tube section sticks during the extension of a mast severely enough to cause it to
crash into its relevant collar, the cause must be investigated immediately. Failure to
do so will result in progressive mechanical damage. The most common causes are
as follows:
Lack of lubrication: See Maintenance section (page 8)
Key sticking in keyway: See Maintenance section (page 13)
Bent or damaged section: Usually caused by overloading mast and/or operating
at too high a wind speed.
If there is no obvious reason for a section to stick, that section must be removed for
inspection and possibly also the next largest section into which it slides.
When fitting optional rotation handles, tighten sufficiently for the components to hold
firmly. DO NOT over-tighten as this can distort the base tube and cause the mast to
stick at that point.
DO NOT remove the exhaust valve in an attempt to retract a mast more quickly,
especially when the mast is carrying a heavy headload, since this action removes
control over the rate of descent. In extreme cases, the uncontrolled collapse of a
mast can lead to the headload being damaged, together with applying shock loads to
the mast fixings.