We have a majority of reviews which praise how quiet the pumps are and yet we get customers who find noise is a problem. We are happy to talk you through solutions but here are a few things to consider. There are two causes of noise.
Turbulence in the pump volute
Turbulence within the pump volute can occur when the pump pumps a mixture of air and water
Vibration from a motor
When the motor rotates the blades of a pump there will always be a degree of imbalance and a vibration ensues. The bigger the pump the more vibration you get so at its extreme a big pump needs to be fitted to rubber pads. The design of the pump is a factor in reducing this but size really does matter and a 12 watt ShowerPowerBooster is inherently quieter than a 1200 watt power shower pump.
The Importance of Resonance
All materials have a natural harmonic frequency so if the vibration created by a SPB matches that of your pipes or wooden joists the noise amplifies (if it does not match the harmonic it fades). Removing pipe clips, preventing pipes touching wooden joists, is a first step to reducing the spread of the vibration, wrapping pipes and even the pump with bubble wrap will muffle the noise. More importantly the bubble wrap can be used to force the pipe away from wooden joists and change the natural harmonic frequency.
In some cases the noise will disappear but if the noise is still an issue you can operate the pumps manually and turn them off when they might disturb. To make this easy I sell a radio remote:-
Noise can be agrevated with certain conditions.
1.0 Air and water in Pump volute.
If the pump is pumping a mixture of air and water it will be much noisier than if its pumping just water. This problem is always associated in a drop in performance from the pump and even ramping up and down of the sound. When a shower power booster pump volute is full of water the sound of the pump is a lower pitch and quieter. If the pump is fitted at a high point in the pipework which traps air – move the pump or adjust the pipework to remove the high point. If the white motor barrel pointing upwards this can trap air – rotate the pump so its level or pointing down. Is the pump being starved of water (blocked valve or hot water cylinder silted up) – replace valve or flush out blockage
2.0 Air in the pipes.
When a shower power booster pump volute is full of water the sound of the pump is a lower pitch and reasonably quiet. A characteristic of a shower power booster is that the pitch of the pump will get higher (but not necessarily louder), as the volume of water you pump decreases, so the tone will rise to a pitch when you turn off a tap. The pump will run on as it compresses trapped air in the pipes downstream of the pump, until the air is pumped to its minimum volume, and then the pump stops. The delay in stopping is in a direct relationship to the volume of air trapped in your pipes, and if the pump stops almost straight way, then you have no air trapped. The higher pitch could cause the pipes to resonate if it matches the harmonic of your pipes so the pump is only noisy when you turn off the shower or tap. The pipes downstream of the pump including any branches leading off the main downstream can trap air. This can be as simple a thing as a feed to a washing machine which was drained of water and now contains air when you fitted the pump. Often air clears on its own but you could try flushing out the individual branches downstream of the pump one at a time. Take off shower heads and tap filters to maximise flow speeds.
3.0 Transference of Vibration through Air
Part of the problem is transfer of vibration from the pump motor and/or the pipe volute to the air.
The Shower Power Booster uses 12 watts of power and it is so efficient that very little heat is created. In a domestic home the pump is not running 24/7 and it is just used for occasional and short periods of time. Surrounding the pump with glass wool, or boxing it in, or indeed any means of muffling the sound is ok with us. It also helps if you insulate the pipes either side of the pumps.
4.0 Transference of vibration from the pump to the pipes.
Transference of vibration from the pump to the pipes, from the pipes to a wooden joist, and the joist vibrates. It could be the pipework itself is resonating. Imagine a violin string drawn over a wire and you can appreciate that from the bow string, to the wooden violin. the amplification of the noise at each stage can multiply and fill an auditorium. The easiest and cheapest thing to do first is to remove fixings where vibration can be transferred to wooden joists. At the same time muffle the noise by wrapping it in bubble wrap which will have two effects.
1.0 It will reduce direct transference of vibrations to the air.
2.0 It will change the natural resonance of the pipe.
You can also replace a short length of copper pipe with plastic pipe either side of the pumps.
5.0 Transference of sound through water.
The vibration will transfer though water so replacing just a short length of pipe either side of the pump may not be enough as the sound jumps from the source, bypasses the plastic pipe, and vibrates a length of pipe further along . In extreme conditions you may need to replace or insulate more pipe. Noise transferred through pipes is uncommon and if you get resonance you are unlucky.
Big pumps can cavitate which sounds like gravel being rolled about inside a pump. A shower power booster can never ever cavitate. Big pumps are naturally noisy but being very noisy can also be because the pump is installed wrongly and the noise you hear is cavitation.
Cavitation is the formation of bubbles or cavities in liquid, developed in areas of relatively low pressure around an impeller. The imploding or collapsing of these bubbles trigger intense shockwaves inside the pump, causing significant damage to the impeller and/or the pump housing.
Traditional shower pumps can create a suction of 1.5 metres of head (0.15 bars), they need to draw water directly from a hot water cylinder through a pipe to the pump only. You need an Essex or Surrey Flange drilled into the cylinder. Fit them on the pipe connected to the vent pipe and they will suck in air, fit them too far away from the cylinder and the head loss in the pipework results in cavitation.
I have spoken to many customers who are replacing noisy shower and I would like to share my observations from a visit to a customer (before he switched to Shower Power Booster). I visited his home in Buckinghamshire on the 5th June 2016 and found a classical example of cavitation where a pump was installed in a convenient place in a bathroom – the pump was very noisy, suffering from cavitation and was pulling air in. It was on its last legs, and it was the 3rd pump installed in 2 years.