Grundfos CR Serie Instrucciones De Instalación Y Operación página 27

Problem Possible cause
2. The pump runs but at a) Wrong direction of rotation.
reduced performance or
does not deliver water.
b) Pump is not primed or is air-bound.
c) Strainers, check or foot valves are clogged.
d) Suction lift too large.
e) Suction and/or discharge pipes leaking. (Pump
f)
g) Pump impeller or guide vane is clogged.
h) Incorrect drain plug installed.
i)
3. Pump cycles too much a) Pressure switch is not properly adjusted or is
b) Level control is not properly adjusted or is
c) Insufficient air charging or leaking tank or piping.
d) Tank is too small.
e) Pump is oversized.
spins backwards when turned off)
Pump worn.
Improper coupling setting.
defective.
defective.
Remedy
Check wiring for proper connections.
Correct wiring.
Turn pump off, close isolation valve(s) and
remove priming plug. Check liquid level.
Refill the pump, replace plug and start the
pump. Long suction lines must be filled before
starting the pump.
Remove strainer, screen or check valve and
inspect. Clean and replace. Reprime pump.
Install compound pressure gauge at the suction
side of the pump. Start pump and compare
reading to performance data. Reduce suction lift
by lowering pump, increase suction line size or
removing high friction loss devices.
Air in suction pipe. Suction pipe, valves and
fittings must be airtight. Repair any leaks and
retighten all loose fittings.
Install pressure gauge, start pump, gradually
close the discharge valve and read pressure at
shutoff. Convert measured pressure (in psi) to
head (in feet): (Measured psi x 2.31 ft/psi = ___
ft). Refer to the specific pump curve for shutoff
head for that pump model. If head is close to
curve, pump is probably OK. If not, remove
pump and inspect.
Disassemble and inspect pump passageways.
Remove any foreign materials found.
If the proper drain plug is replaced with a
standard plug, water will recirculate internally.
Replace with proper plug.
Check/reset the coupling. See page 18.
Check that pressure switch is set and functions
correctly. Check voltage across closed contacts.
Readjust switch or replace if defective.
Check that level control is set and functions
correctly. Readjust setting (refer to level control
manufacturer's data). Replace if defective.
Pump air into tank or diaphragm chamber.
Check diaphragm for leaks. Check tank and
piping for leaks with soap and water solution.
Check air-to-water volume. Repair as
necessary.
Check tank size and air volume in tank.
Tank volume should be approximately
10 gallons for each gpm of pump performance.
The normal air volume is 2/3 of the total tank
volume at the pump cut-in pressure.
Replace tank with one of correct size.
Install pressure gauges on or near pump suction
and discharge ports. Start and run pump under
normal conditions, record gauge readings.
Convert psi to feet (Measured psi x 2.31 ft/psi =
____ ft) Refer to the specific pump curve for that
model, ensure that total head is sufficient to limit
pump delivery within its design flow range.
Throttle pump discharge flow if necessary.
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