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NT 1008-C00 07 18 P BA series e
8. BYPASS (continued)
8.5 Obtaining the flow
If the flow is lower than anticipated, the cause may be
due to incorrect adjustment of the bypass valve. To cor-
rect it, see § BYPASS ADJUSTMENT.
Make sure that the pump is running well at the recom-
mended speed.
If during adjustment, you compress the spring to its limit
or disturb the operation of the motor, without obtaining
the flow required, this means that the motopump unit
must operate with a pressure higher than that for which
it was designed. In this case you should consult our
Technical Services.
When you obtain the required flow, make sure that the
motor can withstand the increased power due to the
overpressure created by closing off the discharge line.
If need be, adjust the bypass again to enable the motor
to obtain it.
8.6 Energy consumption
If the energy consumption does not correspond to
expectations, the reason may be poor adjustment of the
bypass valve.
To correct it, close the discharge valve and adjust the
bypass (see § BYPASS ADJUSTMENT) until the energy
consumption is satisfactory.
8.7 Replacing the spring
Before any disassembly, make sure that the pump has
been drained and take all the necessary precautions to
prevent it from starting up. The pump must not start up,
even accidentally.
Disassembly :
• Loosen the 2 screws
859
.
• Lift off the bypass and place it on a bench or flat surface
free from obstructions.
• Set the bypass pressure to the minimum (see §
BYPASS ADJUSTMENT).
• Keep the bypass vertical during the rest of the process.
• Slowly loosen the screws
856
.
THE SPRING IS ALWAYS UNDER SLIGHT TENSION.
• Remove the cap on the bypass
827
and its pressure
screw (
825 - 826 - 831 - 834 - 835 - 837
).
• Withdraw the bypass spring
824
.
Reassembly :
• Keep the bypass vertical during this process.
• Insert the spring
824
into the bypass. Check the posi-
tion of the valve
823
. It should rest flat on its support
and slide freely in its strainer.
• Replace the bypass cap
827
and pressure screw (
825 -
826 - 831 - 834 - 835 - 837
).
• Slowly tighten the screws
856
.
YOU WILL NEED TO COMPRESS THE SPRING SLIGHTLY
BEFORE YOU CAN TIGHTEN THE SCREWS.
• Check the 2 seals
858
and change them as necessary.
• Refit the bypass on the pump, checking the installation
direction in relation to the direction of operation.
• Tighten the 2 screws
859
equally so the bypass stays
vertical.
• Set the spring pressure to the desired value (see §
BYPASS ADJUSTMENT).
WARNING
INCORRECT SETTINGS OF THE PRES-
SURE RELIEF VALVE CAN CAUSE PUMP
COMPONENT FAILURE, PERSONAL INJURY,
AND PROPERTY DAMAGE.
Hazardous pressure
can cause
personal injury
or property damage.
CAUTION
CAUTION
