Frequently asked questions about pump accessories – answers to what people most often deal with

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Accessories for pumps – answers to the most common questions

When a customer buys a pump, they usually focus on the pump itself – performance, flow rate, pressure. Accessories are often overlooked or considered at the last minute. This is a source of many unnecessary problems – from the pump not showing the promised parameters after installation, through mechanical damage during operation, to premature corrosion of parts that should have lasted for decades. In this article, we answer the questions our customers ask most often – and we do so honestly, without hiding any unpleasant details.

What exactly belongs to the category of "pump accessories"?

This is the first thing to clarify, as everyone has a different idea of what this term means. Pump accessories include all components that are not part of the pump itself, but are necessary or important for its proper installation, operation, safety, and maintenance.

In practice, these are the following product groups:

Mechanical fastening and suspension components – rope clamps, carabiners, suspension ropes, steel wires, chains, consoles. These are mainly used for submersible pumps in wells, tanks, or shafts.
Hydraulic accessories – check valves, shut-off valves (ball, gate), filters before the pump, membrane tanks (expansion vessels), reducers, adapters, elbows.
Electrical accessories – pressure switches, float switches, relay boxes, dry-run protection, frequency converters for speed regulation.
Protective components – protective tubes for cables, cable glands, sealing gaskets for wall penetrations in wells.
Measuring instruments – pressure gauges, flow meters, temperature sensors for the system.

The range is therefore quite broad. This category in the Knowledge Centre mainly covers mechanical and hydraulic accessories, i.e., those related to the physical installation and maintenance of the pump. Topics such as "Choosing accessories according to pump type – submersible, surface, or circulation pumps" and "How to properly secure a pump in a well using a rope clamp and suspension system" go into the individual product groups in depth.

Do I need accessories at all? Can I do without them?

This question comes up surprisingly often, especially when the customer sees how many components are needed for a simple submersible pump in a well. The answer is: it depends on the type of pump and the application, but for most installations, you cannot do without some accessories – or you can, but at the expense of a shorter lifespan or a higher risk of failure.

Concrete examples from practice:

Submersible pump in a well without a suspension rope and rope clamps – the pump hangs only on the discharge pipe. Vibrations when starting and stopping the pump load the pipe-pump connection. After a few years, this can end in a broken connection, the pump falling to the bottom of the well, and a very unpleasant and expensive retrieval. We have seen cases where the pump lay at the bottom of the well for a year before the owner discovered it.
Pump without a check valve – every time it is turned off, water from the discharge pipe flows back into the well. The pump has to start from zero each time, the pressure switch cycles unnecessarily fast, the membrane tank wears out prematurely. In addition, in deep wells, hydraulic shock can damage the pump.
Circulation pump without a vent valve – air pockets in the system reduce hydraulic efficiency and can lead to noisy operation and cavitation.

So no, in most cases you cannot do without the right accessories – or you can, but it is not recommended.

What materials should accessories be made of – and why it matters?

The material question is one of the most important, and it is also an area where customers often save money in the wrong place. The difference between galvanized and stainless steel clamps is not just aesthetic – it is the difference in lifespan measured in years to decades.

Several materials are suitable for pump accessories:

Stainless steel (stainless, AISI 304 or AISI 316) – the gold standard for everything that comes into contact with water, especially for submersible pumps. AISI 316 is more resistant to chlorides (suitable for salt water or water with higher mineral content). For example, see the stainless steel rope clamp – this type of clamp is specifically designed for environments with long-term exposure to moisture.
Galvanized steel – a cheaper alternative, suitable for less aggressive environments or for temporary installations. In the moist conditions of a well or shaft, it starts to corrode after 3–7 years, depending on water quality and the thickness of the zinc layer.
Brass – a standard material for valves, check valves, reducers in potable water systems. Good corrosion resistance, mechanical strength, approved for contact with drinking water.
Plastic (polypropylene, polyethylene, POM) – light, cheap, good chemical resistance. Used in low-pressure applications, filters, some valves. Not suitable for higher temperatures (above 60–70 °C) and less mechanically durable.

In the Knowledge Centre topics "Stainless vs. Galvanized Clamps and Fittings – Which Last Longer" and "Corrosion and Mechanical Damage of Accessories – Causes, Prevention, and Solutions", you will find detailed comparisons with specific resistance figures and practical examples.

What is the correct rope diameter and swivel strength for a submersible pump?

This is a technical question that customers often address – and where mistakes are most commonly made. The answer depends on the weight of the pump, the depth of the well, and the safety margin you want to have.

Basic sizing rule:

Determine the weight of the pump from the technical data sheet (typically 5–25 kg for standard household submersible pumps).
Add the weight of the water in the discharge pipe (at a depth of 30 m and pipe DN 32, this is about 25 kg extra).
Multiply the result by a safety factor of at least 3–5 (for static suspension systems).
Select the rope and rope swivels based on the result.

Practical example: a 12 kg pump in a 40 m deep well. The PE DN 32 pipe with a water column weighs about 32 kg. Total load = 44 kg. With a factor of 4 = 176 kg minimum strength of the suspension system. For this load, a rope with a diameter of 4–6 mm and a strength of 300–500 kg is typically used, together with stainless steel rope swivels of the corresponding diameter.

Important note: the rope swivel must match the rope diameter. A swivel for 4 mm rope does not hold a 6 mm rope and vice versa. The topic "What diameter and strength does the rope swivel need for your pump?" systematically addresses this issue with tables of diameters and strengths.

Where are rope swivels mounted and how many are needed?

Another practical question. Rope swivels are used to create a loop at the end of the rope or to connect two ropes – without the need for welding or crimping terminals. For the pump suspension system, at least two swivels are typically used at each mounting point (top attachment at the well head and bottom attachment at the pump).

Why at least two? One rope swivel can theoretically hold the load, but under dynamic stress (pump vibrations, hydraulic shocks), it can gradually loosen. Two swivels installed correctly (slot = body of the swivel on the working rope branch, not on the dead branch) reduce the risk to a minimum.

Correct placement of swivels:

First swivel: as close as possible to the loop (about 10–15 cm from the eye).
Second swivel: at a distance of 6–7 times the rope diameter from the first swivel.
With higher load or longer rope: a third swivel further along.
The slot of the swivel (U-bolt) is always on the shorter (dead) rope branch, not on the working (load) branch.

A detailed installation procedure is described in the topic "Step-by-step installation of pump accessories – a guide for DIY enthusiasts."

Do I need to buy a check valve when purchasing a pump?

The check valve is one of the most underestimated components. It prevents water from flowing back through the discharge pipe after the pump is turned off. For most household installations with a submersible pump and a pressure system (membrane tank + pressure switch), a check valve is practically mandatory.

Reasons:

Protection of the membrane tank – without a check valve, water drains back through the pipe after each shutdown, and the membrane tank has to compensate for the entire volume. The membrane wears out prematurely.
Fast pump cycling – the pressure switch reacts to the rapid pressure drop (because water has drained back) and unnecessarily turns the pump on frequently. This increases energy consumption and motor wear.
Water hammer – in deep wells, the rapid return of the water column can cause water hammer, which can damage the pump or connections.

We have seen installations without a check valve where the membrane tank wore out in 3 years instead of the standard 8–12 years. The price difference between a check valve (typically 5–20 €) and a membrane tank (80–300 €) speaks for itself.

How can I tell if the accessories are damaged and need to be replaced?

Accessories for pumps are not repaired – they are usually replaced in case of failure. It is important to know what to look for during regular inspections. The frequency and procedure for inspections are detailed in the topic "Maintenance and inspection of pump accessories – what and how often to check."

Visual and functional signs of damage:

Rope swivels – rusting, corrosion (even surface corrosion, not just spot corrosion), loosening of nuts, deformation of the U-bolt, cracked surface. Swivels with visible corrosion should be replaced immediately – their strength can be reduced by 50–70 %.

Ropes and wires – broken strands (even a single one is a warning sign), stiffness (usually due to internal strand corrosion), rust spots along the rope.

Check valves – the pump runs too often (the valve leaks and water flows back), or you hear tapping or vibrations in the pipe after the pump is turned off.

Membrane tank (expansion tank) – the pressure in the tank has dropped below the specified value (check the air valve), or the pump cycles more than 10–15 times per hour under normal consumption.

Filters and pre-filters – visible dirt, pressure drop after the filter by more than 0.5–1 bar compared to the state with a clean filter.

Can pump accessories be installed by oneself?

For most mechanical accessories (rope swivels, suspension systems, check valves with threaded connections) – yes, provided you have basic manual skills and follow the correct procedure. For the electrical part (pressure switch, motor protection, frequency converter) and anything that affects the electrical installation, professional qualification is required.

For DIY installation of mechanical accessories, it is important:

Always check the tightening torque according to the manufacturer – for a 6 mm cable clamp, a typical torque is 10–12 Nm.
Do not use tools unsuitable for stainless steel (steel pliers without protection can leave iron particles on the stainless steel surface, which will then corrode).
Always ensure sealing connections with Teflon tape or sealing compound approved for drinking water.
After installation, perform a pressure test before embedding or covering the installation.

The topic "Common mistakes in the installation of pump accessories and how to avoid them" maps the most frequent errors – from the wrong direction of a check valve (yes, it really happens), through the use of unsuitable seals, to forgetting the air vent at the highest point of the pipe.

What is the price of pump accessories – where can you save and where not?

Customers often ask us where it is reasonable to save and where not. Based on practical experience with orders, the following applies:

Where you can save:

Membrane tank – a medium price category (not the cheapest, but not premium) usually provides a good price-to-quality ratio.
Pressure gauges and thermometers – the difference between a cheap and an expensive product is minimal for home use.
Certain plastic fittings in the low-pressure section (supply to the pump) – a plastic DN 32 for a few cents works just as well as a more expensive brass one at low pressures.

Where it is not worth saving:

Suspension cables and cable clamps – these are safety components. A stainless steel cable clamp costs a few euros, while pulling a pump from the bottom of a well costs hundreds. There is nothing to discuss here.
Check valves – a cheap check valve with a leaky flap is worse than none, because it creates a false sense of security. A quality check valve made of brass or stainless steel costs 15–40 € and can last for decades.
Sealing materials – Teflon tape or sealing compound approved for drinking water is not a place to experiment with no-name products.

How to choose accessories for a specific type of pump?

Different types of pumps have different requirements for accessories. A brief overview:

Submersible pump in a well or shaft: A suspension cable with stainless steel cable clamps is essential, a check valve (either integrated in the pump or external), a protective pipe for the power cable, a pressure switch or frequency converter, and a membrane tank. We also recommend a filter before the pump (a coarse filter, so-called pre-filter) in wells with higher sand content.

Surface pump (self-priming or centrifugal): A suction basket with a check flap at the end of the suction pipe, fittings and hoses for the suction and discharge circuit, a pressure switch, and a membrane tank. Suspension cables are not used here.

Circulation pump (boiler circulation pump): An air vent, ball valves for service disconnection, wall-through fittings, and possibly control valves for flow adjustment. The topic "Choosing accessories according to pump type – submersible, surface or circulation" provides a detailed breakdown of this division.

Can I use accessories from another brand than the pump?

Yes, most pump accessories are standardized according to thread dimensions (G 1", G 1¼", G 1½", etc.) and are not tied to a specific pump brand. An exception are only some proprietary connectors from premium manufacturers – but even there, you can use reductions to standard threads.

Practical tip: always check the diameter of the pump's discharge nozzle (in inches or millimeters) and the type of thread (external/internal, metric/tubular) before purchasing accessories. With this information, you can easily choose the correct reducer, fitting or valve regardless of the brand.

What if I find cheaper accessories without labels and certificates?

Unlabeled accessories without CE marking and without a conformity statement for contact with drinking water are unsuitable for drinking water installations and are illegal in many countries including Slovakia. Materials without certification may contain harmful substances (lead, cadmium), which can leach into the water. In addition to the health risk, there is also legal liability – in the case of selling real estate or in the case of an insurance incident, an unqualified installation with non-certified materials can be a reason for rejecting the claim.

In the case of garden or technical water use (not for drinking), the criteria are less strict, but still, non-certified materials without an identifiable manufacturer are risky – you cannot determine the actual mechanical properties or resistance to corrosion.

Most frequently asked questions (FAQ)

How many cable clamps are needed for one suspension point of the pump?

At least two cable clamps for each suspension point (on the eye of the cable). One clamp can gradually loosen under dynamic stress (pump vibrations). Two clamps properly installed and spaced (6–7× cable diameter) ensure reliable attachment. For heavier pumps (over 20 kg) or depths over 50 m, we recommend three clamps.

Can I use a galvanized clamp instead of a stainless steel one if it is cheaper?

We do not recommend this in the wet environment of a well or shaft. A galvanized clamp will start to corrode relatively quickly – depending on the water quality, typically within 3–7 years. The result can be the pump falling to the bottom of the well. The price difference between a galvanized and stainless steel cable clamp is small compared to the cost of pulling the pump out of the well or replacing it.

How can I determine if the check valve is working properly?

The simplest test: after turning off the pump, observe the pressure gauge. The pressure should drop slowly after shutdown (by 0.5–1 bar over several minutes) – this is normal loss in the diaphragm tank. If the pressure drops rapidly (to zero within 30–60 seconds), the check valve is leaking and water is flowing back. Another sign: the pump starts too often (cycling), even if you are not using water and nothing is being consumed.

What is the safety factor when selecting a suspension system and what value should I use?

The safety factor is a number by which you multiply the actual load (pump weight + piping + water) when selecting rope and shackles. For static suspension systems in wells, a standard safety factor of 3 to 5 is used. This means: if the actual load is 50 kg, the suspension system capacity should be at least 150–250 kg. A higher factor is suitable for older or less inspected installations, where you cannot accurately estimate dynamic loads (vibrations, hydraulic shocks).

Do I need to maintain the pump accessories or is it enough to install them once and forget about them?

Accessories require regular inspection – ideally once a year, best in spring before the season. Check the visual condition of the suspension components (corrosion, loosening), the function of the check valve (see the previous question), the pre-charge pressure of the diaphragm tank (air valve, pressure gauge check), and cleaning of the pre-filter. Neglecting inspections leads to failures occurring at the worst possible time – in summer when water consumption is at its highest.

Do I have to use the same pipe diameter as the pump inlet?

Not always – it depends on the pipe length and flow rate. A general rule says that the suction pipe circuit should not be narrower than the pump inlet (otherwise a vacuum and cavitation occur). The discharge circuit can be increased by one size in long runs (e.g. from G1" to G1¼") to reduce pressure losses. Reducing the pipe diameter below the pump inlet is always a mistake. Use reducing fittings for transitions between diameters – and always in the correct direction (narrowing in the flow direction only on the discharge side, never on the suction side).

Conclusion – Accessories are not an accessory, they are the basis of a proper installation

After years of working with customers and dozens of solved installations, we can say with certainty: most pump failures and premature replacements are not related to the pump itself, but to the underestimation or omission of accessories. A rope that breaks, a check valve that leaks, or a shackle that fails due to corrosion – these are real scenarios we have seen many times.

Properly dimensioned and high-quality accessories extend the life of the entire system, reduce failure rates, and ultimately save money. Topics such as "How to choose the right accessories for a pump – what to pay attention to" or "How to properly secure a pump in a well using a rope shackle and suspension system" will help you go through the entire selection and installation process step by step – with real technical depth and without unnecessary simplification.

Do you have a question about this topic?

Not sure what to choose or dealing with a specific situation in your home? Write to us – we are happy to help.