Shower Power Booster

Easy | Efficient | Effective

Shower Power Booster

Easy | Efficient | Effective

ShowerPowerBooster Fault Finding -All Models - Shower Power Booster

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Shower Power Booster pumps are very reliable and have no inbuilt obsolescence so they last many years. When they do stop sensing flow, or stop performing as well as they did, the led light on an automatic SPB will flash or not flash, and the pump will behave in a particular way which tells the user what is wrong. With a customer care package we will not only advise on diagnosing problems, we will listen to recordings of your pump running,  review photos and sketches, and we will suggest solutions.

This Fault Finding Guide deals with pumps bought in (2012 Mk 1 pumps) to 2018 (last Updated in January 2017). If you have bought a new pump many of these issues have been eliminated because we have improved our pumps.

If it has been running well for weeks, months, or years, and then it stops, a quick look at the led light will tell you if the power supply has failed and if the light shines constant then run the pump in manual mode to see if it starts up. You can normally enjoy a good shower by running the pumps in manual mode until you get round to a full diagnosis.

It could be just air in the system and running the pump manually will clear the air so if it works on manual bypass then put it back to automatic mode and perhaps job done.

If you are fitting the pump for the first time, you may have something that needs sorting in your plumbing system which could be the very thing which makes you low flow and pressure worse. At one time I thought to market showerpowerboosters as a plumbers diagnostic device.

Sorry if this list of faults seems long but even it a problem occurs in 1 in 10,000 pumps, and I have only seen it once, it is worth listing. Some problems are so easy to fix. Did you accidentally turn the thermostat up on the hot water cylinder to very hot which causes the anti-scale on the mixer tap to restrict the flow of  water because it is too hot? Please scan the page to the end as I constantly up date this page and your problem may be very rare and just added as a footnote out of sequence with other problem of a similar nature.

No light = No power = possibly a lose connection = possibly the fuse in the transformer plug failed = possibly the transformer has failed.

Check to see if the pump will run directly from the transformer on manual by unplugging the male jack plug from the flow switch and plugging it directly into the pump motor. 

Slow Flashing Light = Transformer failed – there is a surge protection device in the transformer which can fail.

Check to see if the pump will run directly from the transformer on manual by unplugging the male jack plug from the flow switch and plugging it directly into the pump motor.

Fast Flashing Light = water is flowing through the flow switch – the flow switch has a rotor which turns when the flow exceeds 1.5 litres a minute – the rotor is magnetised and any change in magnetic field is sensed by a hall detector – when the rotor turns the hall detector senses this and makes the light flash quickly.

Light alternates between flashing quickly then it pauses and gives a solid light and then it starts flashing quickly again = air trapped in your pipes = turn off the power and wait until the light fades away – turn the power supply on again – the light should be constant and pump should stop = you have confirmed air in pipes.

You can either try to flush out the air or fit a 22mm single check valve between the pump and the hot water cylinder or the pump and the cold water tank. 

The first thing to check is if the LED light is on and flashing quickly when the pump is running.
Switch the transformer off (the light goes out after a few seconds)
Keep unplugged for a minute (this resets the switch)
Switch the transformer on and you get a constant light only then it could be air. If the pump just starts running then its wired up wrong.
If I were standing by the pump and the above did not help I would carry out the following observation and ask myself the following questions:-
Does the LED just keep flashing quickly at the same rate?
If it does then perhaps
1.0 The mixer is letting hot water cross into the cold system
2.0 The non return valve in the Flowflex Fitting is jammed open.
Does the LED flash quickly and then pause for a moment (the pump stops) and then the LED starts flashing again and the pump starts again?
3.0 There is excessive air in the system

Common & Uncommon Problems – their symptoms and remedial action

1.0 Problem – Debris in Non Return Valve (only applies to pre 2016 pumps)

1.0 Problem – Debris in Non Return Valve Within The SPB (Pre 2016 models)
Small particles of limescale, plastic, metal swarf, etc, can get lodged in the non-return valve. This can happen some time after installation so a pump running well for a period of time suddenly develops issues. The non return valve held open can result in water bypassing the flow switch. The non return valve held open can result in water circulating around the fitting such that when the tap is turned off the pump continues pumping. The non return valve held open can result in loss of performance as a proportion of the water simply re-circulates around the fitting. If the valve is wedged open then flow no longer goes trough the flow switch so it stops sensing flow. Depending on how far open the non-return valve is being held will determine the severity of each symptom.

‘The pump does not turn on automatically”
“It used to turn on automatically but now it doesn’t”
“When the tap is turned off the pump continues pumping.”
‘I am disappointed with the pump because it is having little or no effect on the shower /tap’
“The pump is running but its not as good as it was’’

Customer Solution Available – Debris can be cleared simply with a pencil or biro (see video)

Problem – Air Trapped in pump
If fitted on horizontal pipework the pump should be rotated so that air cannot get trapped in the pump, having said that I have seen so many people with pump barrels sticking up in the air like a sore thumbs that did not have air trapped that perhaps it is not .The pump runs very fast when not pumping in water and will not add pressure.Since the air blocks water from passing the flow switch rotor it will not turn on

‘I am disappointed with the pump because it is having little or no effect on the shower /tap’
‘The pump does not turn on automatically”

Customer Solution Available – Loosen the Compression Joints and Rotate The Pump.

3.0 22mm pipe blocking inlet to pump (only applies to pre 2015 pumps)
22mm pipe blocking inlet to pump (2013 version of pump only)
The chrome plated fittings are designed as slip joints such that it is possible to block or partially block the inlet to the pump by pushing a 22mm pipe into the fitting.

‘The pump does not turn on automatically”
‘I am disappointed with the pump because it is having little or no effect on the shower /tap’

‘When I bypass the flow switch the pump works but the pump seems to spin very quickly with a high pitch sound’

Customer Solution Available – Refit The Pump.

Temperature Of Hot Water – Too Hot
A mixer tap will balance hot and cold to get the temperature you need. If you need so little hot water to get the temperature you need ,the flow on the hot will drop or in extreme conditions the anti-scald will kick in. There is so little hot water required to get the temperature you need that the cold pressure is dominant in determining the effect.There is so little hot water required to get the temperature you need when the hot water eventually reaches the mixer that there is not enough flow to keep the rotor turning or the anti scald is cutting in and out.The anti-scald is cutting in and out or when the hot reaches the tap the flow needed reduces so the flow switch cuts out.

‘I am disappointed with the pump because it is having little or no effect on the shower /tap’
‘The pump turns on automatically and then cuts out or pulses’
‘The pump Pulses’

Customer Solution Available – Turn the temperature down.

Pump fitted before Vent pipe
If the pump is fitted before the hot water vent pipe it will increase the pressure by only 600mm and hot water will be pumped into the cold tank.

‘I am disappointed with the pump because it is having little or no effect on the shower /tap’

Customer Solution Available – Refit The Pump After Vent Pipe.

Problem – Air in Pipes
Air is compressible so when the tap is turned off the pump compresses the air until fully compressed – when the pump stops the water is pushed back through the flow switch and the pump turns on again. Presence of air can also increase the resistance of the pipe and result in very low flows.

‘When the tap is turned off the pump continues pumping.’
‘The pump does not turn on automatically”
‘I am disappointed with the pump because it is having little or no effect on the shower /tap’

This problem can only be diagnosed when other problems are eliminated although continuous running of the pump is a good indication that air in the system is the problem once debris in the non return valve is rectified or eliminated.

Air is trapped if the pipe work is not laid in such a way that it has a constant fall from the vent pipe to the tap/shower and in some cases the only way to achieve this has been to re-lay the pipework in a loft.

Customer Solution Available – Wait as it often cures itself
Customer Solution Available – Re-lay Pipework.

If the problem persists a 22mm single check valve can be fitted near the pump to stop air pushing back through the pump when the pump stops pumping

6a Pump fitted on wrong pipe
The pump needs to be fitted on the pipe which feeds the shower or tap needing boosting. If it’s a hot pipe then simply run the shower tap without the pump running and check that the pipe on which the pump is fitted is getting hot.

‘The pump does not turn on automatically”
‘I am disappointed with the pump because it is having little or no effect on the shower /tap’

Customer Solution Available – Refit The Pump on the correct pipe.

7.0 Cold Water Pressure is too low to balance Hot
Mixer Tap Fails to Balance Hot and Cold Flow
Most mixer taps will balance differential hot and cold pressures of between 4 and 5 to one and for this reason a single pump on the hot will suffice. A few mixer taps are very poor at balancing pressures. Check the cold feed to the tap/shower and if the cold pipe is getting hot then water is recirculating back to the cold tank.


‘When the tap is turned off the pump continues pumping.’
‘I am disappointed with the pump because it is having little or no effect on the shower /tap’

Customer Solution Available – Turn down Hot Water Temperature
Customer Solution Available – Upgrade to a SP22S

8.0 Mixer Tap Fails to Balance Hot and Cold Flow
Mixer Tap Fails to Balance Hot and Cold Flow
Most mixer taps will balance differential hot and cold pressures of between 4 and 5 to one and for this reason a single pump on the hot will suffice. A few mixer taps are very poor at balancing pressures. Check the cold feed to the tap/shower and if the cold pipe is getting hot then water is recirculating back to the cold tank.


‘When the tap is turned off the pump continues pumping.’
‘I am disappointed with the pump because it is having little or no effect on the shower /tap’

Customer Solution Available – Turn down Hot Water Temperature
Customer Solution Available – Upgrade to a SP22S

Mixer Specifications

The right shower head is critical to a good shower

9.0 ‘When the tap is turned off the pump continues pumping.’
The main reason that a pump will not turn off is that there is air in the system and if so this can be an intermittent problem.

The air is compressed when the pump runs and when you turn off the tap or shower the air compresses. When the air is compressed to its maximum extent the water flow stops and the pump stops.

The air no longer subject to pressure created by the pump now expands pushing the water back towards the hot water cylinder and the cold water tank and on its way passes through the pump. The pump sensing the flow thinks you want water again and starts up.

If this is what is happening the light flashes quickly when pumping, then there is a short period when the pump stops and the light is on constant, and then the pump starts again, the light flashes rapidly, and the cycle repeats.

Turning the pump on, wait until the light fades, and then turning the pump on again resets the pump.

If you can clear the air then all well and good but if the problem persists fit a 22mm non return valve near to the pump and this will prevent back flow.

Another reason that the pump continues to run when flow is not required is that somewhere in your house a mixer tap is letting water by. This water is passing through the pump on its way to the cold water tank.

If its the hot water boosted by your shower power booster getting to the cold side of a gravity system you will feel cold pipes getting hot and this hot water will eventually find its way into the cold water tank. The solution is to fit a non return valve on the cold pipe.

If its a mixed gravity and mains pressure system, turn the Showerpowerbooster off and go to the cold water tank in the loft and after a while the cold tank will start to overflow.

A further reason could be the pump itself. There is a rubber seal around the non return valve within the body of the showerpowerbooster and this on very rare occasions has been twisted in such a way that it can let by water. If it lets water bypass by 1.5 litres a minute or over the pump will continue pumping continuously. An annoying factor can is that because the rubber seal moves when the water is hot it may only let water by when the water is cold so when you want a quick splash of water at night to wash your hands it keeps running but during the day when you use lots of hot water its fine. This problem is associated with a loss of performance. The problem was first discovered in a home in Northampton who had a pump that worked well and did everything thing he wanted in the morning first thing but later in the day the pump did not do so well, a second pump in Mansfield only ran constantly at night but not during the day.

If the pump has stopped working but has been working for a while without problems then something has changed. If you have just installed the pump then any one of the things below may apply subject to which pump model you have.

The flow switch needs around 1.5 litres of water to turn on so the first thing to ask yourself is if the flow from the tap or shower head is above 1.5 litres a minute, and then if not why not.

Causes for a drop in flow are:-

1.0 Shower Head needs cleaning.
2.0 Tap or shower filter blocked
3.0 Filter protecting SPB blocked
4.0 Air in pipes
5.0 Shower or Tap Mixer control jammed.
6.0 The temperature of the hot water has changed to very hot so the mixer scald protection is holding the water back (far more common than you would think).
7.0 The mixer anti-scald has gone haywire and thinks hot water is very hot when its not.
8.0 Was something done which is recent and may have reduced flow?

If you have 1.5 to 1.8 litres a minute and the pump is no longer automatic then it might be the pump, with earlier models it could be the non return in the SPB that needs cleaning (easy task and all you need is a biro)

If the filter protecting the pump is blocked this could account in the fall in flow rates, earlier models with-out filter protection (Pre 2016), may have debris in the non return valve or flow rotor.

Take the pump out and check it.
Carry out pre-fitting checks to see if the flow switch works

The flow switch for a ShowerPowerBooster will work with around 100mm of head in a free flowing system as unlike a power shower pump the pump is turned on and off using a magnetised flow paddle (a traditional power shower pump asks for 1,000mm).
The pump activation is not due to pressure differential but at 1.5 litres a minute the water paddle revolves and a hall detector measures the number of times the paddle rotates.
We have sold pumps purely to activate at a low flow to increase the flow to make a bigger pump come on so we know what we sell is good but sometimes the flow is below 1.5 litres a minute before the pump flows so there is need to think of a work around:
Change the shower head – the greatest resistance to flow is often the shower head. We sell an excellent shower head so changing to our shower head will often give you enough flow to kick start the pump.
Change the shower hose – if you have a shower hose with an internal bore of 8mm or less, the only fit place for it is in a bin. We sell low cost shower hoses with 10mm internal bore.
Drop the shower head to start it flowing at or above 1.5 litres a minute, then return it to height when the pump starts.
Bypass the flow switch and turn the pump on and off manually at a 3-pin socket, or simply make it come on and off by wiring it into the light switch.
Use a remote control to turn it on and off (we sell these for £10).

Flow Rotor Blocked (pre 2016 models) only
PTFE tape, jointing compound, or indeed any other debris introduced into the water can tangle around the flow rotor and prevent it activating the pump. Since the blockage can occur at any time it could be the pump works fine for a while and then the volume of water required to activate it increases or it stops activating automatically completely.

Flow Cassette Slipped (2013 models only)
This problem was prevalent in earlier MK 1 pumps and has been addressed by quality control measures at the factory. The brass cassette can be seen through the larger of the clear tubes connected to the pump.

If after carrying out the checks we can talk you through options and a new pump will be sent to you. This is on condition that after you switch over the pumps we will want the old pump back.

Insufficient Water Reaching The Pump
Provided enough water reaches a pump it will pump up to 9 litres a minute and send it on its way to your shower or tap. If there is insufficient water reaching the tap then it will drain the water from the vent pipe until such time as it runs out of water.

When the pump has run out of water the pump will spin quickly as it will have dragged in air and with air in the pump volute the pumping efficiency will drop. When the efficiency of the pump drops, this allows the incoming water to ‘catch up’ and re-prime the pump – the pump is happy again commences to pump whatever water it has.

A pump pumping water water can be identified by a lower tone from the pump and as soon as it exhausts the water supply the process repeats. The fault can lie in not turning on the shut off valve after the pump is fitted, a faulty shut off valve, sediment in the hot water cylinder which is blocking flow, air in the pipework between the cold tank and the hot water cylinder.

A pump running in a part mixture of air and water will be far more noisier than one pumping with no water or one pumping with its volute full of water and it could even sound like something being strangled.

A Shower Power Booster can only pump water if it has water to pump.
In a typical gravity system, the water feeds from the bottom of the cold water tank into the bottom of the hot water cylinder – hot water exits from the hot water cylinder.
From the top of the hot water cylinder, hot water travels horizontally through a 22mm pipe. There is a vent pipe which terminates above the cold water tank, and a pipe which may go down to feed your shower, or your shower may be fed off the vent pipe in the loft.
When you fit a SPB the pump may want to pump double your normal flow. The pump is supplied with water from the cylinder, providing the water from the cylinder can be doubled, the pump pumps continuously.
If the water that is supplied is restricted then the pump starts off pumping what it can get from the cylinder plus some water in the vent pipe. When the vent pipe runs out of water the pump draws a mixture of air and water and it spins ineffectively, so although the motor is still running, the pump stops pumping water.
When the pump stops pumping water the flow from the cylinder fills the vent pipe up again, the pump is re-primed and starts pumping again – cycle repeats.
The sound of the pump varies as the speed increases (trying to pump air), and then decreases (pumping water).
If you disconnect the tap or shower you are trying to improve you could check the flow through a ‘free discharge’.
If this is your problem then look to potential problems in and around your hot water cylinder:
The stop tap on the cold water feed to the bottom of the cylinder is the normal culprit. It may be partially closed or corroded and often you find a new gate valve with an old gate valve left in place on the cold pipe feeding the cylinder.
Other things to look out for is scale in the hot water cylinder, in the cold water tank, airlocks in the cold feed.

Typical customers find:-

‘The pump pulses’

‘The pump is noisy’

Customer Solution – Resolve pipe or cylinder problems

Pulsing Pumps – Airlocks
In any conversation with a customer I like to find out if there is a fundamental problem with the pipework.

Airlocks prevent the full effect of the pumps being received as energy needed to increase flow and pressure is wasted in pushing air about. As the air moves the resistance to flow changes and this can cause pulsing.
This is a real report from a customer survey:

January 14th 2015 – Mr Harrison – Wymondham Norfolk
Problem Reported – Pulsing pump

Reason for Problem
In order to feed the shower a 22mm pipe had been taken from a point near the hot water cylinder – up into the loft – across the loft – and down to the shower. This effectively trapped a column of air which had no way of being vented from the pipe installed.

Solution to Problem
Mr Harrison connected the pipe to the hot water vent pipe in the loft, with the pipe falling all the way to the shower, eliminating trapped air. I received this email just a couple of hours after I left him:

Hi Alan
Thanks for coming around this evening it was nice to meet you, I have changed all the pipework around and so far, so good, we have had two showers and it hasn’t pulsed so looking good. I like fitting these pumps now!

Excessive Back Pressure

If you have a mixer tap or shower which is pulsing then reducing the back pressure may stop it pulsing.

If you do not have a mixer then pulsing pumps are either due to lack of water or in very rare occasions air in the pipes.

There are several steps to identifying where you might have created excessive back pressure and its best to look at the easiest things first unless there are obvious causes of air locks.

Shower Head

The shower head is not the cause of fluctuating pressures but changing the shower head could solve the problem. A shower head will create a back pressure as it restricts the flow deliberately to accelerate the water to create a nice spray pattern. Change the shower head, remove any flow restrictors in the shower head and you may reduce the back pressure and solve the problem. If you physically remove the shower head and it still fluctuates then you know changing the shower head could solve the problem. If it’s a tap it could be a gauze filter on the tap spout that needs removing.

Shower Hose

If it is not the shower head then could it be the shower hose is inadequate. Some shower hoses have an internal bore of 6mm or 8mm and needs to be replaced with a high bore shower hose (minimum internal bore 10mm). Remove the shower hose and the flow still pulses then change to a 10mm hose (but change to a high flow shower hose anyway as it is a good way to reduce hydraulic losses)


Check the filter in the tap spout and consider cleaning it or removing altogether.

Pulsing Pumps – Caused by Mixer (Oversensitive Temperature Cassette)”]

Mixers are less likely to pulse if you pump both hot and cold but for most people a single pump on the hot gives good shower and the mixer does not pulse. Many mixers which pulse at one temperature and pressure are fine if you change the temperature and pressure.

Thermostatic Mixers have a cassette which may be oversensitive

A thermostatic mixer will try to balance the hot and cold feeds. The mixer will therefore restrict the flows to achieve this.

When a mixer has not reached the temperature it wants, it will prioritise the hot port until hot water arrives. Once hot water arrives at the mixer it will reduce the flow on the hot port and increase the flow on the cold port to try to give the temperature you need. If the cassette is slow to act it may overcompensate and open the cold port too much and close down the hot too much resulting in fluctuating temperature and pressure (pulsing pump).

The degree of fluctuation is affected by temperatures, pressures, and differential pressures between the incoming hot and cold. The shower head and shower hose can also have a dramatic effect, and any single change can eliminate the problem.

We have found that changing from a single pump on the hot to pumps on the hot and cold often solves this problem, reducing temperatures can also work. However, the single most effective solution is to change a shower head to a WrightChoice shower head.

There are plenty of ways to change things. The temperature of a typical hot shower is 42 degrees centigrade. The following table compares the volume of hot and cold water to achieve a 6 litre a minute shower at 42 degrees centigrade:-
Requirements for a 6 litre a minute shower at 42 degrees centigrade:

Temperature of Hot Temperature of Cold
65 Degrees C 15 Degrees C
54% 3.24 litres/min 46% 2.76 litres/min
3.3 metres head 4.4 metres head
60 Degrees 15 Degrees
60% 3.6 litres/min 40% 2.4 litres/min
2.25 metres head 3.8 metres head
55 Degrees 15 Degrees
67.5% 4.05 litres/min 32.5% 1.95 litres/min
2.9 metres head 1.9 metres head
45 Degrees 15 Degrees
90% 5.4 litres/min 10% .6 litres min
2.1 metres head 4.2 metres head

Troubleshooting and maintenance guides for thermostatic mixers will typically state their mixers will deal with differential pressure of 5:1 however SPB know from experience that some mixers do struggle and within the same brand, make, and model, some mixers cope, others do not.

For one particular customer with a Bristan Shower Mixer he persevered and was delighted when he achieved a ‘perfect shower’ when he double boosted hot and cold to effectively give him mains pressure on the hot and on the cold.

[accordion_toggle title=”11a. Noisy Pumps”]

Reasons why a pump might be noisy are:-

1.0 Vibration from the motor

2.0 Noise created in and around the pump rotors
2.1 Cavitation
2.2 Air Water Mix in Pump Volute

The initial source of the sound may be small or significant but it can be amplified or attenuated and sometimes even masked by the sound of the shower itself.

3.0 Transference of that sound is
3.1 Through air
3.2 Through pipes
3.3 Through 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 side on which water flows into a pipe is called the pump suction and a pump can literally suck water (and air) towards it. The head of water upstream is an important factor in avoiding cavitation and cavitation is one thing you never want in a pump.

If a pump has a suction potential of lets say 1 metre, it can reduce the water pressure by 1 metre, this is typical for many power showers. Provided you have got a one metre head before the pump then you are fine, but if not the pressure drops to a dangerously low level, the dew point of water.

You get the same effect when you open a bottle of fizzy pop and the bubbles escape but with a bottle of pop you may get soaked with water, in a pump, millions of microscopic bubbles are formed which form and then quickly implode causing high pressure shock waves. The intense shock waves cause the pump blades to erode. Excessive noise and vibration are a clear indication that you have cavitation.

If you started with one metre static head upstream of a pump then this will be reduced by the friction head loses through a pipe which increases with the volume of water pumped. Friction loss through a pipe is proportional to the square of the diameter of the pipe and the linear length of the pipe. For a big pump you need to install the pump as close to the source of the water (in a home this means next to the hot water cylinder), and keep the pipe size as big as is practical.

The good news for ShowerPowerBooster is that it will never cause water to cavitate.

Air & Water Mix in Pump Volute

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 louder), as the volume of water you pump decreases, so the tone will change to a slightly higher 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.

When a pump is full of air the resistance to rotation of the rotor blades is minimal so the pump spins. The pitch of the pump is higher than when its pumping water but it can also be much quieter. Not having water in a pump volute can be a dangerous thing for a big pump because a big pump needs a flow of water to take the heat away from the pump (or the motor will burn out). A shower power booster does not need a flow of water to take the heat away so it will run dry 24/7 without damage.

When a pump is presented with a mixture of air and water in the pump volute then the turbulence in the volute will result in a noisy pump. For bigger pumps this is probably because big pumps are good at pulling in air and were incorrectly installed. Big pumps need a separate connection to a hot water cylinder and should never be fitted to a pipe connected to the vent pipe from a hot water cylinder. A shower power booster can also be noisy if its pumping a mixture of air and water and it could simply be the SPB is fitted with its motor pointing upwards, the volute is a high point, and traps air. Having said that, many people do fit SPB with the pump barrels pointing up and never have any trouble. Shower Power boosters are deliberately designed to have a low suction pull so instead of a minimum of one metre head, 0.05 metres head will probably be ok for a SPB. The SPB has not pulled in air, but there is simply not enough water to pump. If a SPB is noisy it could be air and a simple test is to check the maximum flow to the shower or tap you are trying to boost. Checking the flow from another tap is probably good enough. If there is not enough water coming from the cylinder you may also experience a pulsing pump as the pump takes way water it can from the vent pipe before running out of water and so look at the pulsing pump topic as well if this happens.

Mitigation Of Noise From Pumps.

Transference of sound through 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.

Transference of sound through pipes

Just like a bow being dragged over a violin,  smallest of vibrations can be amplified and spread. For most this is not an issue and the pumps are unobtrusive, but for some, the rigid copper pipes in many homes can transfer the vibration from the pipes to the fabric of the building. If the resonance of the vibration matches the harmonic resonance of the fabric of the building the noise can be amplified. For most its not a problem but for one customer in Doncaster the noise was spread through his home. Putting and elastic band on the pump barrel to pull it towards another pipe changed the vibration of the pump such that it no longer matched the harmonic frequency and the noise was substantially reduced. A simple step is to avoid the pump barrel touching woodwork, or you could replace some of the pipework either side of the SPB pump with plastic pipe.

A practical way of changing the harmonic frequency of the pipes and stopping the sound being transferred to the air is to add lagging to the pipes. Lagging the pipes will muffle the noise and also insulate them giving the added advantage of less heat loss and gain to the pipes.

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 more pipe. Noise transferred through pipes is uncommon and if you get resonance you are unlucky.

Vibration and harmonics are a  a science in itself as the video below amply demonstrates a famous tragedy where the harmonic frequency cause by a particular wind speed caused a disaster.



3.1 Through air
3.2 Through pipes
3.3 Through water

12.0 A challenging mixer tap or shower mixer (pressure)

13.0 A challenging mixer tap or shower mixer (Volume)

14.0 Do lights flashing on the automatic tell me what the problem is?

This video gives you a general overview of the whole system which I hope you will find of interest. For specific problems and their solutions please read on.



Cold Water Pressure is too low to balance Hot

If the flow of cold water to a mixer tap is insufficient to maintain the temperature of a shower or tap, the mixer may reduce the hot flow to match the cold if it has anti scald in the mixer or the hot will overwhelms the cold.

‘I am disappointed with the pump because it is having little or no effect on the shower /tap’
‘The hot overwhelms the cold at the shower or tap”

Customer Solution Available – Upgrade to a SP21S or SP11S

Upgrade with a SP1



A challenging mixer tap or shower mixer (pressure)
Some mixer valves are only suitable for mains pressure or very high gravity pressures. Even some showers specified as suitable for 1 metre head (0.1 bars) are barely adequate when they have this pressure. A shower power booster will typically add 3 metres head to an existing shower with 1 metre existing head to give a really great shower as the shower has 4 times the minimum it needs.
With the exception of the UK and the Republic of Ireland the rest of Europe is predominantly a pressurized system such that mixers needing 0.5 bars or even up to 2 bars is needed (20 metres head). A SP21S or SP11S will add up to 8 metres head to a typical challenging shower such that the pressure can satisfy most shower mixers.

‘I am disappointed with the pump because it is having little effect on the shower /tap’

Solution – put the cold on mains pressure if possible and double boost the hot or double boost hot and cold. Upgrades to SP21S or SP11S available on web site.

Upgrade with a SP1U


A challenging mixer tap or shower mixer (Volume)
A rain shower needs far more water than a standard shower so without balancing hot and cold the hot water will be restricted.

‘I am disappointed with the pump because it is having little effect on the shower /tap’

Solution – put the cold on mains pressure and double boost the hot or put a second pump on the cold to achieve balanced flow.

Upgrade with a SP1U

If a transformer trips out then it results in a slow flashing LED light on an automatic pump or with a manual pump the pump just pumps in short bursts. In November 2013 we received a batch of 200 number 2 amp 12 volt transformers. Many of these transformers have tripped out in service below the current they should trip out. We only ever bought this one batch of 2 amp transformers – all others are 1.5 amp and 3 amp. If you have a 2 amp transformer then whilst most are still working this tripping out is a possible cause of failure.
14.0 Do lights flashing on the automatic tell me what the problem is?

See section on lights

Alan Wright
This page was started on 10th September 2014 and is constantly reviewed.