31
©Godiva Ltd. Our policy is one of continuous development. We therefore reserve the
right to amend specifications without notice or obligation.
Vacuum Test
Place the blanking cap(s) in position on the inlet(s) of the pump and close the delivery
valves. Run the pump at 1300-1500 rpm and observe the vacuum/compound needle.
When a vacuum of 0.81bar is obtained, stop the pump. This vacuum should be
maintained for at least 15 seconds or drop no more than 0.07bar in a minute.
If the pump will not hold the vacuum with the blanking caps in position, a leak is present
in the pump, and the pressure test detailed below must be carried out to trace it.
Should the pump not reach a vacuum of 0.81bar but will hold a lower pressure, a fault in
the priming system is indicated.
Pressure Test
– carried out without pump running.
This test is to be carried out if the pump will not hold a vacuum with blanking cap(s) in
position, and is intended to trace the leaks responsible for the loss of vacuum.
Apply a water pressure of 3.5 - 7.0 bar to the pump and check for leaks. The area
causing the leak should be visible, and can be dismantled and rectified.
Check each primer drain hole for water leakage. If leakage is found, replace the primer
seals and O rings as described in the Maintenance Manual Procedures.
If the pump will not achieve 0.81 bar vacuum, and will not hold what it does achieve,
there is a leak, and possibly also a fault, in the priming system.
If no leaks are apparent, the leakage must lie between the priming valve and the primer.
Points to be checked are:
The inlet seal in the primer end cap
The priming valve diaphragm
Water Ring Primer (optional priming system)
If a water ring primer is fitted carry out the same vacuum test as described above but
run the pump at 2300rpm to achieve a vacuum.
Should the pump not reach a vacuum of 0.78bar but will hold a lower pressure, a fault in
the priming system is indicated. Check as follows
–
See that the primer drive (fibre pulley) is engaged with the pump pulley and runs without
slipping. When the primer is in the engaged position there must be a 3mm clearance
between the lift-off pad attached to the primer and the lift-off piston just below.
Figure 28
When water ring primer is in engaged
position (fibre pulley is running in
drive flange) there must be a 3mm
gap between lift-off pad on primer and
cylinder piston below.
