Owner's manual

Series 322 Load Unit Maintenance
71
10. Turn on high hydraulic pressure. If pressure was reduced at the hydraulic
power unit, restore full pressure.
11. Briefly turn the Lift Control to the lift crosshead position to pressurize the
lift cylinders. Then return it to the stop crosshead position.
12. Unlock the crosshead and exercise the crosshead. Then return to the stop
crosshead position. Raise and lower the crosshead to check for smooth
operation. Lock the crosshead.
13. If the crosshead does not move smoothly, go back to Step 4 and continue
from there.
Load Unit: Adjust the Hydraulic Locks
Hydraulic locks might need adjustment if the crosshead still moves jerkily after
bleeding the lift cylinders. Adjustment might also be needed if the crosshead
slips under full load.
If adjusting the hydraulic locks does not fix these problems, call MTS.
1. Turn on electrical power at the controller. Do not turn on hydraulic pressure
yet.
2. If the crosshead is already at a comfortable working level with no specimen
installed, proceed to Step 3.
If not, position the crosshead for a comfortable working level. Proceed as
follows:
A. Reset any active interlocks at the test controller.
B. Turn on high hydraulic pressure.
C. If there is a specimen in the load unit, remove it.
D. Move the crosshead to a comfortable working height.
The crosshead can slowly drift down the columns if the locks are turned off
and the hydraulic pressure is turned off.
The crosshead can damage any test fixtures, grips, and specimen in its
path.
Unlock the crosshead only to reposition it. Always lock the crosshead after you
have repositioned it, and never leave the crosshead unlocked.
3. Remove the covers on the ends of the crosshead. The crosshead covers must
be removed to adjust the hydraulic locks. Four 1/4-20 screws (two top, two
bottom) on each cover need 5/21 hex (not included). Hand-tighten when
reinstalling the covers.
CAUTION