Most of the problems lie with the fact that water hates being moved. Here are some ways to reduce the noise:
- Don’t over-tighten the screws on the base. Over-tightening the pump’s attachment screws compresses the rubber mountings, hindering their ability to absorb sound energy.
- Have a truly rigid mounting base. If you knock on the proposed base and it responds like a drum, it’s going to worsen pump noise. Another effective solution is to place a small piece of carpet between the pump and its base.
- Use the thinnest hold-down screws that will adequately hold the pump.
- Use flexible piping. It is surprisingly effective at dampening sound - try including about 350 mm of truly flexible piping between in a very loose loop between the pump and any hard plumbing on the pump inlet and outlet. If they are unable to move freely a lot of noise will be transmitted via these pipes. The difference in transmitted noise is so great that it can be worthwhile connecting each pipe using a full loop.
- Avoid elbow fittings close to the outlet port. They cause turbulent water flow and also back pressure – both of which generate noise. Use smooth curves rather than right angle bends.
- Prevent vibration in the wall cavity. Another cause of transmitted noise including water hammer is vibration where plumbing passes through a wall. During installation ensure the pipes are unable to move especially where they go through a wall. Use plastic foam or insulation to keep them in place.
- Trapped air causes plumbing to rattle. It is desirable to bleed all air from the system to prevent this.
- Add an accumulator tank. This will dramatically reduce the noise, pulsation, pump circulation and will extend the life of your pump. The result is a smooth and quiet stream of water.
If you follow these steps you will have a pump which makes no more noise than a good sewing machine. Truly.