Dawson HPH 1200, User Manual

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It is good practice to start piling with the hammer set on minimum stroke, this limits unnecessary
damage to both the hammer and the pile when the pile can be driven easily. The stroke may then be
adjusted to suit the changing driving resistance.
On certain piling jobs, it may be possible to start driving on pairs of sheet piles, changing over onto
a single sheet pile as the driving resistance increases (this will give maximum productivity.)
3.4.4 Cold running/overtravel
The hammer 'jumps' on the pile top when trying to achieve full stroke if the hydraulic system is
'cold.' If this happens, the hammer will
stop automatically. (Thus preventing internal damage to
the unit.) The power pack will continue to run and the 'pressure' gauge will read approximately 240
bar.
In order to reset the hammer, turn off the 'power' selector on the hand control pendant and stop the
power pack. Allow the engine to stop for approximately 10 seconds then restart the unit. Reduce
the stroke of the hammer to minimum. Run the hammer at this lower setting until the oil is warm
enough to allow correct full stroke setting. If reducing the stroke does not cure the problem, warm
the hydraulic oil as described in section 3.3.1.
If the hammer overtravels again, refer to the Troubleshooting section 6.0.
THE HAMMER WILL NOT RUN IF IT IS NOT ALLOWED TO RESET CORRECTLY
3.4.5 Refusal
Piling must stop with this hammer when the rate of driving reaches 10 blows per 25mm.
Continued use will result in hammer and/or pile damage