TST-020 PT-AIR
– REV. 2017-246
Page 4 of 14
VACUUM GENERATING SYSTEM TEST
Note: The following assumes operator has access to suitable plugs, a
ball valve with vacuum gauge, and additional hose and adapter fittings
for connecting the ball valve to the lifter’s vacuum lines and fittings.
The most likely leak points in the vacuum generating system are the
check valve, the filter, or the control valve. Leave the filter disconnected
(capped-off) from the pad system and test:
1) Isolate the check valve from the system.
The check valve
(2A)
is attached to the venturi assembly.
See
FIGURE 2
.
2) Remove the hose
(2B)
from the venturi assembly connected to the
fitting with the check valve.
Using the ball with vacuum gauge and appropriate hose adapters,
attach the ball valve (end with vacuum gauge attached) to the
fitting where the hose was removed. Attach the other end of the
ball valve to the hose that was removed from the fitting.
See
FIGURE 3
.
3) With ball valve in the open position (handle in-line
with valve), apply vacuum. When a sufficient level
of vacuum is reached, close the ball valve (turn
handle perpendicular to the valve) and close the air
supply valve to the venture air pump.
4)
Observe both the lifter’s and ball valve’s vacuum
gauges:
If the vacuum level of the lifter’s vacuum gauge
starts and continues to drop, a leak is located in
either the vacuum filter or control valve assembly.
Proceed to step 5
.
If the vacuum level of the ball valve’s vacuum
gauge starts and continues to drop, or if both the
vacuum gauges hold steady and do not drop, this
indicates that the check valve leaks.
Note: The check valve may leak intermittently, so
if both vacuum gauges hold steady and do not
drop, the check valve is indicated as the cause.
If the ball valve’s vacuum gauge did drop and
indicates a leak: Check the attached fittings and
line connecting to the vacuum tank for loose
connections or indication of damage or cracks to
the fittings or lines. If there is no visible damage
or neither vacuum gauge indicates a leak during
the test, replace the check valve.
FIGURE 2
2A
2B
FIGURE 3
