Wood’s Powr-Grip MRT49DCO - Manual (Page 14)

Rev 12.0/5-13 12 MRT4-DCO-DVS: #35071
Reading the Vacuum Gauges
The lifter is equipped with 2 vacuum gauges, which indicate the current vacuum level in each
circuit of the lifter’s vacuum system. The green range indicates vacuum levels sufficient for
lifting the maximum load weight, whereas the red range indicates vacuum levels that are not
sufficient for lifting the maximum load weight. Both gauge needles should show a sudden surge
in vacuum as the vacuum pads seal against the load. If it takes more than 5 seconds for the
vacuum level to reach 5" Hg [-17 kPa] on either vacuum gauge, press on any 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 both vacuum gauges, except when used at high
elevations (see SPECIFICATIONS: Operating Elevation). If not, make sure both vacuum switches
are adjusted correctly (see MAINTENANCE: V
ACUUM
S
WITCH
A
DJUSTMENT
). If either 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 both vacuum gauges, due to leakage in the seal
between the vacuum pads and the load surface. 6 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
: Cleaning), and reapply the lifter to the load. If the load has rough or porous
surfaces, the operator must conduct a test to determine whether the lifter is designed
to lift the load , 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, disconnect the electrical connector uniting the battery
with the vacuum generating system.
Note: After the test is completed, move the valve handle to the “RELEASE” position (power
off ) before reconnecting the battery.
4) Raise the load a minimal distance, to assure that it is supported by the lifter.
5) Monitor both vacuum gauges 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. 7
6
Contaminated loads can also cause the vacuum pump to run frequently or continuously. Since excessive pumping quickly
reduces battery energy, the operator should clean the load when possible, to minimize pumping.
7
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.