12v Water Pumps - Most asked Questions & Answers

Why do we sell so many different 12v water pumps?

At Water Pumps Now Australia we sell a wide variety of 12v and 24v water pumps for use in recreation vehicles such as caravans, motorhomes, RV’s, campers, boats and camping, and for use around the farm.

Depending on your pump application and the flow required, you may need a submersible pump, freshwater pressure pump, diesel pump, camping pump for a shower or a chemical pump for the farm. There are many options which can be confusing if your knowledge of pumps is basic or not at all. In this case, contact us by either email or phone and we’ll step you through your pump selection.

To help you with your selection and for easier browsing our pumps are listed under either ALL PUMP PRODUCTS or PUMP APPLICATIONS. Simply follow the drop downs of All Pump Products if you know the type of pump you require or follow the drop down for Pump Applications to search under the application your pump is required for. EG: Pump applications, Caravan Pump, Caravan water pumps 3+ outlets. This will give you a smaller choice of pumps to look at which are specific to your requirements. You will find a pump choice to suit all budgets.

What does water pump flow rate mean?

Every pump can achieve a certain flow rate which is expressed as either gallons per minute or litres per minute. EG: A FL35 12v pump which has a maximum flow rate of 12.5 L/min will fill 12.5 litres of water in a bucket in a minute.

Most caravans and RV homes require a water pump flow rate of around 10 L/min. A flow rate of 10 L/min or more will cover the pump should someone be in the shower, and someone washes their hands at the sink at the same time. The pressure pump with the highest flow is not your best choice. Always choose the correct pump for your outlets and usage to eliminate high amp usage on your battery.

What is pump cycling?

Cycling is when your pump turns on and off quickly when it is operating. Pump cycling happens when the flow rate of the pump is higher than the output of the tap or outlet.

EG: The pump is rated at 17 L/min and the outlet is open at 5 L/min. This will cause pump cycling.

How do I stop pump cycling?

  • You require an accumulator tank between the pump and the outlet
  • You need a pump with a built-in by-pass
  • You need a variable speed pump

Your pump system will be greatly improved with an accumulator pump. The accumulator sits beside the pump and is roughly the size of a large grapefruit. For further information on why you require an accumulator tank in 12v water pump systems please visit our pump FAQs.

How many amps does a 12v water pump use?

The amount of amperage used to run a 12v water pump varies dependent on the pump, its maximum litres per minute and its pressure. When we look at 3 different brands which are commonly used in caravans and their maximum amperage, you can see the amperage goes up with the pumps motor size required for the maximum water flow to be achieved.

  • Single tap 12v water pump - Our smallest 12v pump, the Escaping Outdoors FL2202 will deliver a maximum 5 L/min using 3.3 amp.
  • 2 - 3 tap 12v water pump – The Jabsco Par-Max 3 (delivering 11 L/min at 40 PSI will use 6 amp.
  • 3 – 4 tap 12v water pump – The Shurflo Aquaking 11, 12v water pump delivering 15 L/min will use 10 amps

How do you test a 12 volt water pump?

If your DC 12v electric water pump is not working it is best to follow a checklist to find out if the pump motor is burnt out, the pressure switch has failed and needs replacing, or the battery is dead.

The main reason we see 12v water pump failures is due to the setup not being correct for the pump being used. When your pump fails there are tests which can be done to help find the problem.

Test if the pressure switch has failed. Your pressure switch can fail to protect the pump from further use by stopping it. Pressure switch failure mainly happens to protect the pump if there is an in-balance of pressure in the pump system. Your pump is often still in good working order but not operating due to the switch not operating.

To test for a failed pressure switch, follow this link.

If your switch is the issue, then replace the pressure switch and modify your pump system so it doesn’t happen again or purchase a 12v pump which better suits your application. Noting, it is not about whether a pump is cheap or dear it is about whether the pump is a good choice for your application and if the setup is correct for the pump you have chosen. If you are unsure of how to set up your pump properly, please contact our pump technicians. They are here to help.

After you have completed the pressure switch test which has bypassed the pressure switch to turn on the pump motor you will now have a pump motor which is either working or not working. If the pump motor is not working, your motor has most probably burnt out and you will require a new pump. If the motor is working, you will require a new pressure switch and will need to make modifications to your setup so the issue doesn't occur again.

Please contact us to make sure the pump you choose and how it is set up will best meet both your budget and your application to ensure a smooth 12v water pump system.

How does a 12 volt water pump work?

When you open a tap or outlet the decrease or drop of pressure in your pump system disengages the pressure switch. This in turn tells the 12 volt water pump to start. When you turn the tap or outlet off the diaphragm engages the pressure switch which turns the When the water reaches a pre-set pressure, the diaphragm engages the pressure switch which turns the power off at the pump. When the tap is opened a drop or decrease in pressure in the system disengages the pressure switch and this in turn tells the pump to start up.

What brand of 12v water pump is best?

This is a question we are often asked. The answer depends on the application the pump is for and working with the budget of the buyer. At Water Pumps Now we offer a wide variety of 12v water pump brands to cover these varying needs of our customers. After finding out the application the pump is required for and the flow required, our pump technicians will give you the best pump options to suit you.

Some of our popular and best-selling quality pumps are:

  • Escaping Outdoors FL35 – 12.5 L/min at 35PSI. Great for caravans up to 3 outlets
  • Escaping Outdoors FL2202 – 5 L/min at 35PSI. Great for single tap use for caravan or camping sink.
  • Jabsco range of Par-Max pumps – 5 sizes in caravan style freshwater pumps delivering 11L/min to 22.7 L/min
  • Shurflo range of 12v water pumps – 3 sizes in caravan style freshwater pumps 11.3 L/min to 19 L/min
  • Rule range of 12v and 24v bilge pumps. A wide range of sizes in automatic and non-automatic to suit all boat sizes

Can I replace a 12v water pump myself?

Yes, you can replace a water pump yourself. All 12v water pumps come with installation instructions on how to install your pump. Simply follow the instructions or contact us for assistance. Whether you are setting up a 12v pump for a cabin, a caravan, a boat or campervan, the process is still much the same.

If you are unsure of which pump is best for your application, give us a call and we will step you through the process to make sure you get a system that works well. Noting: A good 12v pump system will require a non-return valve between your water supply and the pipe to your pump and possibly an accumulator tank dependent on your pump choice for a quieter and trouble-free pump system. Check out our other FAQ’s for pump set-up tips.

How long will a 12v water pump run on battery?

If your 12v DC water pump says it is 5.5amp draw, this is the maximum draw under load when in use.

For example: a 10Ah battery would be able to supply 10 amps for one hour, 5 amps for 2 hours, 2.5 amps for 4 hours

If using the 5.5 amp draw pump as an example the battery will run for 1. 81 hours.

What battery do I need for a 12v water pump?

Depending on how long you want to run the battery between battery re-charge for your pumps use, you will need a battery that will service your pump and all your 12v needs you may require at one time.

Noting: Most batteries will not be able to supply their full Ah rating when used at or below a certain discharge rate. The discharge rate will be listed in the spec sheet of the battery, but a common rule of thumb is to take away 1/20th of the Ah rating. EG: A 10Ah battery would lose 0.5 amps.

Therefore, when using a 10 Ah battery you would not be able to use a pump or combination of 12v goods together which operated at over 9.5 amp.

If using a 20Ah battery you would lose 1 amp. If using a pump and other 12v goods you will need the combined amp of them to be under 19 amp.

Do I need a non-return valve on my 12v pump system?

A non-return valve is highly recommended for all 12v pump systems. Pump failure can often be attributed to not having a non-return valve. The valve is also known as a check valve. Its purpose is to make sure the water only flows one way. This stops water flowing back into the water tank and keeps the pump primed with water in the system. If your pump is gravity fed it also prevents head pressure causing pump damage. if you water storage has the hose dropping into it you will require a foot valve instead of a non-return valve.

Do RV 12v water pumps need to be primed?

The pump doesn’t need to be primed but you will enjoy a much smoother and quieter operating system if your pump is kept primed. It is as simple as adding a non-return valve or foot valve to your system.

Can I run my 12v water pump dry?

A feature of many 12v water pumps is run dry protection. This allows the pump to run for a short period of time whilst dry without causing pump damage. Make sure you pump has this feature before purchasing. Your pump requires water to keep it cool while running which is why they can only be run dry for very short periods or you risk burning the motor out.

Why do 12v water pumps burn out?

There are quite a few reasons your 12v water pump has burnt out and we are happy to trouble shoot with you over the phone to see why this has happened to your pump. The most common reasons are:

  • An in-balance of pressure in the system
  • Air in the system
  • Head pressure on the pump. related article (FAQ - why has my pressure switch failed to early)
  • Pump running dry

12v pump issues are easily eliminated with the use of the correct pump for your system, an accumulator tank if required, a non-return valve at your water source and keeping an eye on your water supply to make sure it is not too low.

How do I install my 12v water pump?

It is important to mount your 12v water pump correctly to protect it from wear and tear and fatigue on the fittings and to eliminate pump vibration. Your pump mounting whether it has rubber feet, or a metal base plate should be on a solid foundation with bracing to prevent vibration.

If possible, mount your pump vertically with the motor at the top in the most convenient position for accessibility whilst being protected from the weather. Do not mount your pump under your caravan or campervan unless it is fully enclosed from road or water splash or being knocked. This area should be well ventilated to avoid overheating of your pump.

Your connecting pipe work must be flexible, so the pumps vibration doesn’t transfer to another area. Leaving a bend of flexible pipe of roughly 300 mm before a fitting or straight section of pipe will help as the vibration gets lost in the bend if it is able to move freely.

            Typical 12v 24v 240v Escaping Outdoors water pump set up

Do I need a filter on my 12v water pump?

A filter or screen filter is highly recommended to prevent debris and dirt which can accumulate in your water tank from entering your pump. If it does enter the pump, it can cause damage to the diaphragm. A 12v water pump without a screen filter will not be covered under warranty by any 12v pump manufacturers. The screen filter goes in the line on the inlet side of the pump and is attached to the pump with either a BSP or barbed connection. Most pumps come with fittings and a screen filter but in some cases the screen filter is sold separately.

What connections come with my 12v water pump?

The choice of connections which come with your 12v water pump will vary from one manufacturer to another. The advertisement for each pump should describe and/or show photos of the connections the pump comes with. Typically, a 12v caravan style pressure pump will come with barbed or BSP fittings to suit your pump and may also come with a pre-filter to catch any sediment in your water tank.

Other things to consider when purchasing a 12v water pump

  • What is the voltage you have available?
  • What is the maximum flow rate you will need?
  • What is the maximum pressure your plumbing system is able to handle?
  • What pump connections do you require?
  • Do you need a screen filter? Does your pump choice come with one?

If you are not sure of which pump is best for your application and plumbing system contact us at Water Pumps Now Australia on 1300 411366 and one of our friendly pump technicians can help you with your query.

Paul Girdler

Paul Girdler, Managing Director/ Sales
Water Pumps Now Your Online Pump Shop

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