I recently had to replace the pump on our hydronic heating system. The old pump was 1/15 HP. The serviceman replaced this with a pump that is 1/8 HP. It works fine but there is a humming in the pipes that seems to be caused by the increased “rushing” of the water in through the pipes. I have attempted to remove all air from the system but the sound continues. Do I need to have a lower powered pump installed or is there some other problem. Thanks for your help!
One-eighth horsepower does not use much electricity, so there will not be much savings from changing to less horsepower. The noise indicates the system is affected by the new circulator. Adjusting a balancing valve upstream could reduce the velocity by putting added backpressure against the pump; but if there is none, the cost of installing one and adjusting would be the cost of swapping in another pump. Replacing it is an easy try in comparison.