Checking Pump Performance - Grundfos SP Series Installation And Operating Instructions Manual

6.1.1 Ohm value chart
Motor not yet installed
Motor in well
(Ohm readings are for
drop cable plus motor)

6.2 Checking pump performance

The troubleshooting chart on p.15 may require
that you test the pump's performance against its
curve. To do so, perform these steps:
1. Install pressure gauge
2. Start pump
3. Gradually close the discharge valve
4. Read pressure at shut-off.
5. After taking reading, open valve to its previous
position.
6. To calculate pump performance, first convert
psi reading to feet.
(For water: PSI x 2.31 = ____ ft.).
7. Add this to the total vertical distance from the
pressure gauge to the water level in the well
while the pump is running.
8. Refer to the specific pump curve for the
shut-off head for that pump model. If the
measured head is close to the curve, pump is
probably OK.
14
Ohm value chart
Ohm
value
2,000,000
(or more)
1,000,000 (or more)
500,000 - 1,000,000
20,000 - 500,000
10,000 - 20,000
Less than 10,000
Megaohm
value
recommended procedure
2.0 New motor.
Used motor which can be reinstalled in the
1.0
well.
0.5 - 1.0 A motor in reasonably good condition.
A motor which may have been damaged
0.02 - 0.5 by lightning or with damaged leads. Do
not pull the pump for this reason.
A motor which definitely has been
damaged or with damaged cable.
0.01 - 0.02 The pump should be pulled and repairs
made to the cable or the motor replaced.
The motor will still operate, but probably
not for long.
A motor which has failed or with
completely destroyed cable insulation.
0 - 0.01 The pump must be pulled and the cable
repaired or the motor
replaced. The motor will not run in this
condition.
Condition of
motor and leads/