New Holland T7030 Operator's Manual page 240

Operation
When starting the engine with a trailer connected into
the tractor air brake system, chock the wheels and
release the parking brake and footbrakes. The
warning light (1) Figure 190, will illuminate until air
pressure builds up to 4.5 -- 5.5 bar.
The pressure will continue to rise, as indicated by the
air pressure bargraph in the Dot Matrix Display,
Figure 191. To select the air pressure bargraph, use
the CAL/SEL switch or, where fitted, the enhanced
keypad.
The air tank(s) should reach operating pressure
within 3 minutes of start--up but may take longer,
dependent upon the size of the trailer brake
reservoir(s).
Once required pressure has been reached a loud
'pop' will be heard, signifying that the unload valve
has opened to allow excess pressure to escape to
atmosphere.
IMPORTANT: Apply the footbrakes several times,
ensuring that the pressure, as indicated by the
gauge, drops as the brakes are applied and rises
again when they are released. Never drive the tractor
with the trailer brake warning light on.
IMPORTANT: When the footbrakes are applied ,with
the parking brake off, ensure that the front wheel
drive indicator light (1) Figure 192 illuminates and
that all stop lights are functional.
IMPORTANT: Various types of trailer braking
systems are available.
manufacturers' instruction manual before making
connections to the tractor air brake system.
Clean the trailer and tractor connectors before
coupling up the hose(s). Ensure that connections are
secure. Check the trailer brakes regularly to ensure
that they are functioning correctly.
CAUTION
Do not over use the brakes on steep down hill
gradients. Use the same gear going down hill as you
would use for going up the same hill.
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SECTION 3 - - FIELD OPERATIONS
Check the trailer
190
191
192