Wood’s Powr-Grip MRT49DC2 - Manual (Page 22)

Rev 0.5/4-14 20 MRT4-DC2: #35071
B1
B2
Reading the Vacuum Gauges
Two vacuum gauges display the current vacuum level in positive inches of
Hg and negative kPa for the 2 circuits of the lifter’s vacuum system. A
gauge's
green range indicates vacuum levels sufficient for lifting the
maximum load weight (see figure B2), whereas the red range indicates
vacuum levels that are not sufficient for lifting the maximum load weight
(see figure B1). If it takes more than 5 seconds for the vacuum level to
reach 5" Hg [-17 kPa] on either vacuum gauge, press on any vacuum pad
that has not yet sealed.
Vacuum Level on Optimal Surfaces
When the lifter is attached to clean, smooth, nonporous load surfaces, it
should be able to maintain a vacuum level in the green range on each
vacuum gauge, except when used at high elevations (see SPECIFICATIONS:
Operating Elevation). If not, make sure the corresponding vacuum
switch is adjusted correctly (see DIGITAL VACUUM SWITCH
ADJUSTMENT in SERVICE MANUAL for details). If the vacuum switch cannot
be adjusted to maintain a vacuum of 16" Hg [-54 kPa], perform the V
ACUUM
T
EST
(see MAINTENANCE) to determine whether there is a deficiency in the
vacuum generating system.
Vacuum Level on Other Surfaces
When the lifter is attached to contaminated, rough or porous load surfaces, it may not be able to
maintain a vacuum level in the green range on each vacuum gauge, due to leakage in the seal
between the vacuum pads and the load surface.
14 In the case of contamination, thoroughly
clean the contact surfaces of the load and the vacuum pads (see MAINTENANCE: V
ACUUM
P
AD
M
AINTENANCE
: Pad Cleaning), and reapply the lifter to the load. If the load has rough or porous
surfaces, the operator must conduct a load suitability test , as follows:
1) Make sure the lifter's vacuum generating system is functioning correctly (see MAINTENANCE:
V ACUUM T EST ).
2) Apply the vacuum pads to the load as previously directed.
3) After the vacuum pump stops running, place the lifter's power switch in the OFF ( )
position.
4) Raise the load a minimal distance, to assure that it is supported by the lifter.
5) Monitor each vacuum gauge while the load is suspended for 5 minutes:
The lifter must
maintain a minimum vacuum level of 10" Hg [-34 kPa] during this time. If not, the
load does not possess the characteristics required for using this lifter. 15
14
Contaminated loads can also cause the vacuum pump to run frequently or continuously. The operator should clean the load
when possible, to prevent excessive use of battery energy.
15
Certain load materials are too rough or porous to allow the lifter to form a seal which can be maintained for 5 minutes without
power. However, in geographical locations where CE Standards do not apply, it may be possible to use the lifter to lift such loads.
Contact Wood’s Powr-Grip for more information.