The Flow & added value of controllers


In this blog lets look at the value flow controls could add to your business and the advantages in the electronic control of water flow. Exploring the benefits of using flow controls for pump delivery systems. what are some of the costs associated with a WFP business and how an electronic control can save you money, also covering, in brief, the following

What is flow control

How much water is needed

The effects of running a pump at maximum

Can you work more cost effectively and efficiently

How a controller manages a system

Costs – can these be reduced

Flow control means what ever the job you can be assured the right volume of water reaches the glass. As the convenience of tank based systems come to the fore and in particular buffer tank systems that allow pure water to be produced and used on site combined with the benefits of storing water for sites that do not have easy access to water.

In each case the need to have the right water volume to do the job provides flexibility and means you can extend your service offering. 

Pressure dynamics is explored further in another blog. Pressure and back pressure are very relevant to both ensuring the correct water volume is available and that the system is working as efficiently as possible.

If we work on the basis that the majority of pump delivery systems use a 5.2 LPM (1.2 GPM) 8 amp 100PSI pump we can look at the different impacts of pressure on flow volume. The hose will have a maximum expansion capacity which effects the amount of water the hose can carry. Once the hose reaches its maximum capacity any additional water pushed into the hose creates back pressure. This water will not reach the glass. 

Commonly a cleaner with a tank based WFP will use a 100PSI pump capable of moving 5.2 litres (1.3 gallons ) of water a minute. These pumps also have a maximum current rating of 8 amps. The pump has the potential to draw 8 amps of current an hour from your battery if left to run flat out. Lets examine then a system with no means of flow control based on the above pump.

The Pump 

Unrestricted the pump could, in theory, pump 5.2 litres of water a minute ( 5.2 x 60 minutes) = 312 litres (68 gallons) an hour. Pressure is created in the system by the pump, hose wall and jets ( see pressure dynamics blog ) Due to the back pressure created by the system only some of this 5.2LPM will ever reach the glass perhaps 50% (2.6 LPM) in most cases. If we work on the basis that 2.6 LPM is the maximum volume that will reach the glass, this is the maximum available volume and this may not be required at all sites.In the case of regular or light cleans it is very likely lower flow volumes are required. The trick is to have the fleixibility to alter flow as required ensuring that you have the correct volume needed for each site.

Based on our unrestricted pump. If we assume 5.2 LPM is being pushed at the pump outlet into the hose. We have a pump working at maximum capacity with the motor under maximum strain. It will be drawing 8 amps of current an hour from the battery. 

The pump pressure switch is now needed to stop the pump. Running the pump until it hits the pressure switch, means that the pressure in the system will be at its absolute maximum. This puts strain on the hoses, on the fittings and on the pump. It therefore increases the chances of split hoses, leaking joints and increases wear on your pump, shortening the pumps life. As you stop the flow  and rely on the pressure switch to stop the pump. The pump motor is at maximum, working as hard as it possibly can and therefore drawing maximum current from the battery. Hence as the switch opens it is under great strain. The high current and the fact that the pump is under high inductive load (with stored energy) means that the pressure switch contacts are likely to arc and eventually they will fail. The pump is operating at 100% to deliver 50% of the water to the glass wasting 50% of the pump motors energy for no gain. Is this efficient? probably not. But how does running the pump flat out impact the battery

Effect on the battery

Running the pump at its maximum capacity means the pump will get hot, the hotter the pump becomes the less efficient it becomes at moving water. As the pump tries to maintain the high pressure and flow it draws more current from the battery. Resulting in the pump becoming hotter. Drawing 8 amps an hour. This is going to flatten a battery very quickly, As the voltage falls the load on the battery increases meaning, that higher voltage is required to maintain the high amperage output. This, in turn, leads to a combined rapid fall off in both amps and voltage available from the battery. You will likely get three to four hours continuous work and there after the battery will rapidly be depleted.

Constantly depleting the battery to low levels will damage the cells and the batteries ability to hold a charge. This cycle described above will rapidly destroy a battery.

Controlling Flow

So why control water flow? In short water management with a tank based WFP is a factor due to the relative cost of producing pure water. There is also a physical limitation of how much water can be carried. This in turn, limits the amount of work that can be achieved per tank of water. Clearly then using over 300 litres an hour is not sustainable. Also, the question needs to be asked, do you really want maximum flow of water delivered to the cleaning area all the time? Perhaps for rinsing hydrophobic glass or even on first cleans it may be useful, However for the average maintenance clean, less water would be required. So what types of flow control are available?

Manual taps

Aquadapter or Aquatap

kinking the hose

Radio remote on pump

Electronic pump constant flow regulator

While points 1,2 and 3 above give limited control of water volume to the brush head, allowing a start/stop of flow. You are, however, still left with a pump that is running at maximum trying to push 5.2 litres of water to the glass. The actual amount of water is being restricted by the jets and tap, e.g. only 2.6 litres a minute or 50% of the potential flow rate produced by the pump. In short, the pump is operating at 100%, generating 100% pressure and is using the maximum current draw of 8 amps, yet only 50% of the available flow reaches the glass. Although the volume of water has been reduced the pump is still working at maximum, drawing maximum current as outlined above.

Having the right water volume is key to efficient cleaning Simply throwing lots of water at the glass will not give good results. If a section takes 30 seconds to clean simply using more water alone will not reduce that time. Is this efficient use of your resources? Would you drive a car at 30 mph an hour in 1st gear? Of course not, because you would be straining the engine and gear box and using a huge amount of fuel. You would change into a higher gear to allow the engine to operate at lower revolutions, but still give you the required speed for the conditions.

So why would you not do the same with your WFP pump? Use of a manual tap can be a benefit. However in isolation, it will not allow you to use and manage your system in an efficient way. Why reduce the water volume without reducing the speed of the pump? I do actually feel that a pump controller used with a pole tap provides an excellent combination. The controller ensures the pump is working only as hard as needed producing the required water flow efficiently. The tap gives the stop/start capacity to save water as you move between windows. The controller simply sees,s flow has stopped and dead ends the pump. Stopping the pump this way means less pressure in the system, less strain on the pump and less current draw. There are of course many other features and functions designed into a controller as outlined later in the article.

Use of a pump controller and tap combined is a way to create an efficient and managed system

Using a radio remote will avoid the instance of arcing across the pressure switch as the pump is stopped by switching the power off. You are however as above left with a pump running flat out with maximum pressure in the system again giving 5.2 litres of water a minute to the brush head. So how then do you improve efficiency, protect your pump and increase battery life? An electronic pump control not only reduces the strain on the pump by slowing it down It will give the flexibility for you to increase that flow when required.

Pump Controls 

Once we recognise that a system has a maximum flow volume it is time to look at how we ensure the pump produces what we need efficiently. Surely it makes sense that if you only require 30% of the available water volume that you operate the pump at 30% and so on. In my earlier example we have show the maximum is 2.6 LPM so lets have the pump produce this volume. Use of a Pump controller will give just this. Now the pump is not working against it self we will see a reduction in the current draw down to 3 - 5amps, in turn the pump motor is running cooler, A reduction in back pressure also reduces the risk of hoses/connectors blowing out. A control provides real value for money it can help you manage your entire system. Using a controller will reduce current draw by 50% and yet still allow the pump to produce the same 2.6 LPM. This is achieved because the system is now operating more efficiently.

Manage a system is a bold statement:

How can a pump control manage my system? Pressure switch detection: The control monitors pressure in the system yet does not activate the pressure switch. If the pressure switch activated due to very high pressure, the control is telling you that something is causing the high pressure, it could be a twisted or kinked hose, dirt or grit in the hose line or jets, an air lock, a failed connector or possibly worn cable or poor connections.

The Spring control is engineered to operate with the pump pressure switch and monitor it. The common misconception is that the control activates the pressure switch. In fact, it is a high pressure that activates it. Why then do we engineer the control this way? Simply we feel the additional level of protection is justified. On the rare occasion, the control does not DE the pump the pressure switch activates and prevents possible damage and even flooding. Auto calibration: The control is easy to use, Follow the steps or online video to set the calibration to your system.

Once calibrated the control will detect when the water flow has stopped and shut down the pump well before the Pressure switch activates. You can also manually calibrate the control if necessary just to tweak the calibration. By calibrating the unit, we are allowing the control to see the normal operating pressure. Simply use the auto cal feature and in moments, you are ready to work. It works with any hose or Micro bore.

Volt meter: We have added the volt meter to our controls over the last 5 years as it makes fault finding over the phone very easy. Spotting high levels of volt drop – worn batteries and cables or perhaps poor connections. Auto adjusts Once correctly calibrated the control will automatically adjust the pump speed to ensure the selected water flow is maintained as the pole is extended or retracted, ensuring the desired flow of water is delivered at all times to the window.

Low Battery cut off Similar to a number of controls on the market the low battery warning and cut of protects the battery from long-term damage, Our latest control has an easy to use over ride feature selectable from the main menu, Complete the days work then re charge as normal.

Note: It is not recommended that the low battery cut off permanently disabled as the pump will completely drain the battery damaging the cells Advanced Micro DE retest: Once the control detects the water flow has stopped it, will shut down the pump. However the control needs to know when to restart the pump so the controller re-tests for flow stopped every few seconds by turning the pump for a fraction of a second, The test checks for restored flow hover it does this without any increase in system pressure, meaning the control could be left in DE for long periods of time with no risk to the system

12-month manufacturers warranty; We offer a full 12-month warranty together with online support and advice services both via our distributor network and directly if necessary. We believe ongoing support is essential as it keeps you earning together with regular updates.

You can be assured you are dealing with an established UK manufacturer with a long history of electronics. Let us examine the claim that a pump controller is expensive, They can commonly cost between £70 - £90 for a standard unit and a little more for full radio remote and other variants. All our digital controls have all the features listed above as standard. The analogue controls do all the above with the exception we can not display battery voltage or provide a low battery cut off override. Additional features can also allow you to....

Auto fills a water tank

Monitor TDS

Protect a system against frost Monitor water temperature in a hot system

Provide full radio remote

Trickle charge a leisure battery

Mains powered units for static systems

The current controller range represents many years of research and development listening to window cleaners and the features they are looking for, This represents a large cost in time and money to produce a unit that has more processing power than some mobile phones, yet is a fraction of the cost. Used within its design parameters a controller will far exceed its warranty period.

Note: Control must be fitted and used according to manufactures instructions – failure to do so may invalidate your warranty.

While cheaper electronic controllers are available they do not have the features and management capability of our controls. Yes, you can buy a controller for £20 this is of course reflected in the quality of the components, reliability and no warranty. Will the overseas supplier provide support and advice to keep you working? a repair service? Can you contact them when the unit fails? Chances are you will replace the cheap control 2 or 3 times a year as it will burn out. In some cases buying the cheapest unit is a false economy So do you spend £80 - £90 on a state of the art designed for purpose control with full manufacture warranty and support that will give years of reliable service Or Spend £60 - £80 every year on a poorer quality substitute with no additional features, No warranty, no end user support? Plus the lost work time in buying and replacing burned out cheap controls.

So what other costs are involved in setting up your business?

Vehicle, Fuel, Excise Duty, Insurance

Public Liability

System. Poles, Hose, Pumps, Battery, Brush, Jets, Tank or trolley

Pure water production Or Buy pure water

Replacement Membranes, Filters, DI resin

Without a doubt, one of the ongoing costs is water production. The following figures are based on a five-day working week, 6 hours a day, using a 650-litre tank and assume 4 weeks holiday and bank holidays (Total working day 223 a year). We are also working with a starting TDS of 60.

Filling the tank will use 217,425 litres of water a year

The following process via an RO/DI 144.950 litres is produced-additional Polishing

Cost £3551.79 a year

0.024p a litre

Note: The above do not include water rates or water charges via a meter. Also, if the Initial TDS is higher a higher frequency of resin and membrane replacements will increase the per litre cost. A pump can cost £65 - £75 add in your pre-filters Vat and delivery This cost quickly rises to £80.00 - £100.00, Common practice is to carry a spare pump so up to £200, A controller will help reduce the strain on your pump and extend its working life. Recent anecdotal evidence suggests that a pump loses efficiency once it is driven beyond 80% capacity.

I have outlined why it is not efficient to run a pump flat out, benefits of slowing the pump by just 20% mean less current draw. less strain on the pump. less pressure in the system and ability to manage water resource to match flow to need on a job to job basis. If on average a 4 bedroom house uses 20 litres of water. A reduction of reducing water use by 20% is 4 litres lets assume 2 house an hour. Your saving is 8 litres an hour or based on our 6 hour day 48 litres a day. This is a potential saving of up to £11.52 every day based on the figures above.

The cost of the controller than can be recouped very quickly as the whole system operates more efficiently. Add in the features and ability to manage a system a controller represents excellent added value. In summery then a controller will add value to your business and help extend the life of your system. It will reduce your running costs as you only use the water required per job. Less water used means less to produce and in turn, this extends the life of filters and resin. Reduced strain on your pump motor as it now works only as hard as it needed. Reducing the stress on the motor bearing will also mean less heat is generated, Remember a hot motor will be less efficient. Reducing current draw extends the life of the battery allowing you to carry out more work per charge.

Looked at in this context a controller is not a cost but an aid to building your successful business

The decision is, of course, a personal one, are you, however, working as efficiently as you could?