Question: Why is the circulator pump making noise (buzzing or rattling)? Is this normal? What can be done about this?


  • The air in the system leads to noise. The entire system must be inspected and bled.
  • The pumps may be oversized for the system in question. To fix this, throttle the pressure-side valves until the noises are eliminated.
  • The water in the system is boiling because the pump is undersized. This can be remedied by installing a larger pump.
  • Excessive wear of bearings (rattling). The pump needs to be replaced.
  • A system that has already been entered into operation has become clogged. The system needs to be cleaned.

Additional information: