Grundfos SP Installation And Operating Instructions Manual page 30

Problem Possible cause and/or how to check
4. The pump a)
cycles too
much.
b)
c)
d)
e)
30
The pressure switch is not properly
adjusted or is defective.
How to check:
Check the pressure setting on switch
and operation. Check the voltage
across closed contacts.
The level control is not properly set
or is defective.
How to check:
Check the setting and operation.
The pressure in the diaphragm tank
is insufficient or the tank or piping is
leaking.
How to check:
Pump air into the tank or diaphragm
chamber. Check the diaphragm for
leaks. Check the tank and piping for
leaks with soap and water solution.
Check the air to water volume.
The snifter valve or bleed orifice are
plugged.
How to check:
Examine the valve and orifice for dirt
or corrosion.
The tank is too small.
How to check:
Check the tank size. We recommend
that the tank volume is
approximately 10 gallons for each
gpm or pump capacity.
Possible remedy
Re-adjust the switch or replace it if
it is defective.
Re-adjust the setting; refer to the
manufacturer data. Replace the
level control if it is defective.
Repair or replace any damaged
components.
Clean and/or replace any defective
snifter valve or bleed orifice.
If the tank is too small, replace it
with a proper size tank.