Bell & Gossett P86203F NBF 45 Circulator - Manual (Page 18)

Troubleshooting
Pumping system troubleshooting
Symptom Cause Remedy
There is no circulation Air-bound system Vent the system
The impeller or piping is clogged. Locate and remove the obstruction.
The system valve is closed. Open
The electrical circuit for the pump is
broken.
Check all related low and line voltage
circuits.
There is inadequate circulation. Air-bound system Vent the system.
The impeller or piping is clogged. Locate and remove the obstruction.
The impeller is damaged. Replace pump.
The pump is too small. Replace the pump if single speed. If
three speed switch to higher setting.
Partially air-bound pump Vent the pump casing.
Improper motor speed Check the wiring and the voltage.
There is pump or system noise. Entrained air Vent the system.
Pump cavitation Lower the pump or raise pressure or
relocate (see note below).
Excessive water velocity Install balancing cocks or parallel
piping.
Pipe vibration Provide adequate pipe support.
There is premature failure of pump
components.
Improper pump (size/type) Replace
Improper pump location Relocate
Excessive water treatment Check the manufacturer’s
instructions.
Pump operating close to or beyond
the end point of curve.
Balance the system.
Excessive piping load Provide proper pipe support
There are seal failures within a 1–year
period or less in a closed system.
Excessive dirt, sand and oxides Clean the system.
Excessive or improper water
treatment
Check for proper water treatment
recommendations from pump
manufacturer.
Pump Cavitation:
1. Improper selection
2. Compression tank location
1. Check pump operation on its
curve — overloading
2. High head pump must have
compression tank on suction
side of pump.
Excessive temperatures Check the type of seal and maximum
operating temperature from the
manufacturer.
Pumps run without fluid Pumps must be primed before
operation.
There is seal pitting, oxygen
corrosion, magnetic iron oxide.
Caused by wear and excessive
amounts of free oxygen.
Check if system has a constant leak.
Fresh water feeding carries oxygen
into the system.
Troubleshooting
16 NRF ™ -25,36,45/NBF ™ -25,36, and 45 Circulator Installation, Operation, and Maintenance Manual