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The garden pump is the tool of choice for removing water from a rain barrel or cistern. A non-return valve helps to prevent the device from running empty. Our instructions explain how to correctly install the non-return valve in the garden pump.

In a nutshell

  • Non-return valve ensures that the garden pump and suction line do not run dry
  • ideally, the non-return valve is located as close as possible to the intake point of the line
  • if the line is live due to the additional component, the connections and line can be damaged
  • Non-return valve with CE mark stands for minimum quality and functionality

Why a non-return valve?

As soon as you switch on a garden pump with a cistern connection after a long period of standstill, no water comes out despite the pump running. The reason for this is quickly explained: Over time, the suction line of your pump, including the pump chamber, will run empty. The unit draws air and is therefore only partially able to suck in the water from the tank over the distance of the empty line. A non-return valve, on the other hand, closes the suction line when water flows from the pump back into the tank and keeps the line and garden pump filled.

The right check valve

Before actually installing, you should make sure that you select the right check valve, as unsuitable components can do their job but also affect the overall performance of the pump. Therefore, when selecting the valve, pay attention to the following aspects:

  • Suitability for outdoor use
  • Suitability for rainwater (because of sand / dirt etc. in the water)
  • CE marking as general proof of functionality
  • dimension suitable for the cable cross-section
  • material suitable for the intake line (metal line: contact corrosion)

Install check valve: instructions

Now that you know which check valve you want to install, let's move on to the instructions. Step by step, insert the new component into the intake of your garden pump:

Step 1: Determine installation location

First you decide where you want to install your non-return valve between the water tank and the pump. The following relationships are evident here:

  • the closer to the reservoir, the shorter the idle suction path
  • the weaker the garden pump, the less empty line as a target
  • Installation ideally on existing connections / screw connections
  • good accessibility for revision (e.g. in case of dirt) recommended

Tip: In most cases it is between the pump and the suction line at least a connection point that is suitable for quick and easy installation of the valve.

Step 2: Open connection

Now open the existing connection between the pump and the line or between the existing line sections:

  • first open the screw connection using a suitable open-end wrench or pliers
  • Open the flange connections by loosening the screws
  • Loosen and remove other safety devices from plug connections (clamping rings, wire, clamps, etc.).

Step 3: Position the check valve

Now insert your non-return valve in the open line, i.e. between the two parts of the line or between the line and the garden pump. Since the component requires additional space, you should avoid the following constellations by relocating or deforming the line:

  • Bending stress of rigid lines
  • excessive compression of the line
  • Tensile stress on adjacent components
  • lateral loading of the connections due to avoidance behavior

All of these unwanted loads put excessive strain on the lines themselves, but especially on the connection points, which are particularly sensitive points and can lead to leaks or other damage to the material over the long term.

Attention: Be sure to install your non-return valve the right way round. The opening direction must be from the tank to the pump, whereas the triggering - i.e. the line closure - should take place in the event of a reverse flow from the pump to the tank.

Step 4: Restore Connections

Regardless of the exact design of your non-return valve, now connect the line connections to the two open ends of your suction line or suction line and garden pump:

  • Connect the screw connections and hand-tighten
  • Plug in the plug-in connections and press tight
  • Finally, put on and tighten any clamping rings or clamps

Tip: Before connecting all the connections, be sure to check whether the necessary seals are still present or have been reinserted. Nothing is more annoying than a leak from a forgotten component for a few cents.

frequently asked Questions

Do I also need a check valve for a submersible pump?

No, because with the submersible pump technology there is no suction line, as the pump body itself is directly in the water. There is also no need for a non-return valve, because emptying is not possible for the same reason.

Why is the suction line emptying despite the non-return valve?

Even an intact non-return valve is never absolutely watertight. The longer your pump is inactive, the more likely it is that the water level will slowly drop until the line is empty.

How do I recognize an incorrectly installed non-return valve?

The effect of a non-return device installed the wrong way around is fatal. The suction of the pump creates a suction against the opening direction and the flap is pulled shut, so to speak. Due to the negative pressure with a lack of water, the pump can run hot in the long run and be damaged.

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