15
Fig. 14 Plug/valve locations CR(N) 32, 45, 64, 90, 120, 150
Fig. 15 Vent plug
Gradually open the isolation valve in the suction line until a
steady stream of airless water runs out the priming port. Close
the plug and securely tighten. Completely open the isolation
valves.
In open systems where the water level is below the pump inlet,
the suction pipe and pump must be filled and vented of air before
starting the pump. Close the discharge isolation valve and
remove the priming plug. Pour water through the priming hole
until the suction pipe and pump are completely filled with water. If
the suction pipe does not slope downward from the pump toward
the water level, the air must be purged while being filled. Replace
the priming plug and securely tighten. For pumps with Cool-Top®,
see 14. Startup for Cool-Top®.
Follow these steps:
1. Switch power off.
2. Check to make sure the pump has been filled and vented.
3. Remove the coupling guard and rotate the pump shaft by hand
to be certain it turns freely.
4. Verify that the electrical connections are in accordance with
the wiring diagram on the motor.
5. Switch the power on and observe the direction of rotation.
When viewed from the top, the pump should rotate counter-
clockwise (clockwise for CRN-SF).
6. To reverse the direction of rotation, first switch OFF the supply
power.
7. On three-phase motors, interchange any two power leads at
the load side of the starter. On single-phase motors, see
connection diagram on nameplate. Change wiring as required.
8. Switch on the power and again check for proper motor
rotation. Once rotation has been verified, switch off power
again. Do not attempt to reinstall the coupling guards with the
motor energized. Replace the coupling guard if the rotation is
correct. After guards are in place the power can be reapplied.
Note: CR, CRI, CRN 1s to 5: For these pumps, it is advisable
to open the bypass valve during start-up; see fig. 13. The
bypass valve connects the suction and discharge sides of the
pump, thus making the filling procedure easier. When the
operation is stable, the bypass valve must be closed.
.
7.2 Operating Parameters
CR multi-stage centrifugal pumps installed in accordance with
these instructions and sized for correct performance will operate
efficiently and provide years of service. The pumps are water-
lubricated and do not require any external lubrication or
inspection. The motors may require periodic lubrication as noted
in 9. Maintaining the pump’s motor.
Under no circumstances should the pump be operated for any
prolonged periods of time without flow through the pump. This
can result in motor and pump damage due to overheating. A
properly sized relief valve should be installed to allow sufficient
water to circulate through the pump to provide adequate cooling
and lubrication of the pump bearings and seals.
7.3 Pump Cycling
Pump cycling should be checked to ensure the pump is not
starting more than the following.
Grundfos ML motors:
• 200 times per hour on 1/3 to 5 hp models
• 100 times per hour on 7 1/2 to 15 hp models
• 40 times per hour on 20 to 30 hp models.
Baldor motors:
• 20 times per hour on 1/3 to 5 hp models
• 15 times per hour on 7 1/2 to 15 hp models
• 10 times per hour on 20 to 100 hp models.
Rapid cycling is a major cause of premature motor failure due to
increased heat build-up in the motor. If necessary, adjust controls
to reduce the frequency of starts and stops.
7.4 Boiler-feed installations
If the pump is being used as a boiler-feed pump, make sure the
pump is capable of supplying sufficient water throughout its entire
evaporation and pressure ranges. Where modulating control
valves are used, a bypass around the pump must be installed to
ensure pump lubrication (see “Minimum Continuous Duty Flow
Rates”).
7.5 Freeze Protection
If the pump is installed in an area where freezing could occur,
the pump and system should be drained during freezing
temperatures to avoid damage. To drain the pump, close the
isolation valves, remove the priming plug and drain plug at the
base of the pump. Do not replace the plugs until the pump is to be
used again. Always replace the drain plug with the original or
exact replacement. Do not replace with a standard plug. Internal
recirculation will occur, reducing the output pressure and flow.
TM04 4036 0609
TM04 3920 0409
Priming Plug
(Opposite side)
Drain Plugs (G 1 / 2 A)
with 1 / 4” NPI gauge/sensor taps
Discharge
Vent Plug
Suction
Drain Plugs (G 1 / 2 )
with 1/4" NPT gauge/sensor taps
Loosen
center
plug to
vent
pump
Vent
Plug
Motors should not be run unloaded or uncoupled
from the pump at any time; damage to the motor
bearings will occur.
Do not start the pump before priming or venting
the pump; see fig. 15. Never operate the pump
dry.
Grundfos.bk Page 15 Wednesday, March 18, 2009 10:38 AM
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