How to Choose the Right HEPWORTH Components

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The HEPWORTH system is one of the popular solutions for heating and water distribution in Slovak households and with professional installation companies alike. Its advantage is versatility - it can be assembled from dozens of different components depending on the installation you are building. But this very versatility is also the most common source of problems: when someone orders the wrong diameter of fitting, forgets water filtration, or chooses the wrong type of valve, the result is a leaking joint, an unbalanced circuit, or an expensive complaint after a few months of operation. In this article we go through, step by step, how to choose HEPWORTH components in practice, what to watch out for in a common family installation as well as in a larger multi-circuit system, and where mistakes are most often made.

We base this on the everyday practice of installation companies as well as on questions that come to us directly from customers through our advice service - so this is not a theoretical guide, but a summary of situations that are genuinely dealt with in the field every week.

What the HEPWORTH system actually consists of

Before we get into choosing specific components, it is useful to have an overview of what categories of parts you will need when building or renovating a system. In simplified terms, we can divide them into five groups:

Pipe - the distribution pipes themselves, most often in diameters of 15, 18, 22 and 28 mm, carrying water from the heat source to the individual appliances (radiators, underfloor heating, heat exchangers).
Joining materials - compression fittings, which join pipe without needing soldering or pressing, elbows, tees, reducers.
Filtration - mechanical or cyclonic filters, which protect the whole system from deposits, scale, and dirt from the water mains.
Manifolds - components that distribute the medium into several separate circuits (typically for underfloor heating or several radiator branches).
Fixing materials and fittings - clips and clamps to fix the pipe to the building structure, radiator valves, shut-off and control elements.

The mistake we see most often is that someone orders the pipe and fittings, but forgets filtration or a sufficient number of clips - and then has to buy them "on the fly", often from the wrong range or at an unfavourable per-piece price instead of a larger pack.

Diagram of a typical installation - where the water flows and where each component sits

To make it clear how the components fit together, let's look at a simplified diagram of a common installation from the water inlet to the radiator. The order of the components in a real installation matters - the filter should always come before the manifold, not after it, otherwise it loses its purpose.

As you can see, the filter sits right at the inlet, before the first branch - protecting the whole system, including the manifold and all circuits downstream of it. A compression fitting is a typical joining element between straight sections of pipe, the manifold handles splitting into several branches, and the radiator valve at the very end regulates flow to a particular appliance.

How to choose the correct diameter and type of joint

The first question you have to ask yourself when choosing HEPWORTH components is: what flow rate and output does the given branch of the system need to carry? The pipe diameter is not determined by guesswork, but by the heat output of the appliances connected to that branch and by the length of the route (because of pressure losses).

In common practice in family houses, we most often encounter these diameters:

15 mm - connections to individual radiators, short end sections.
18 mm - smaller branches with two to three radiators.
22 mm - main risers in smaller houses, pipework to manifolds.
28 mm - main supply pipe from the boiler in larger houses or with several parallel circuits.

If you undersize the diameter, the system will "hum", flow will be insufficient, and the most distant radiators will not heat up fully. If you oversize it, you will pay unnecessarily for more expensive components, and the system will have a slower response to changes (more water has to be heated before you feel the effect). This is exactly why it is worth working out the diameter from the heating design, not just "by eye" based on what was in a previous installation.

As for the type of joint, the vast majority of residential and family house HEPWORTH installations use compression fittings - they do not require soldering or special pressing tongs, they can be disassembled and reassembled, which you will appreciate especially during servicing a few years later. Their disadvantage is that they require thorough tightening and a straight, undamaged pipe end - even a small scratch on the pipe cut can cause a slow, hard-to-find leak.

Compression fitting for copper pipe - 15x1-EK - a typical joining element for the most common 15 mm diameter, suitable for end connections to radiators as well as shorter straight sections. Dismountable, no soldering required. Price from 2.51 EUR.

When ordering fittings, it is worth calculating a small reserve on top (at least 10% more pieces than the "paper" calculation) - in practice something always gets damaged during installation, or an additional branch is added that was not originally planned.

Water filtration - the component most often forgotten

Filtration is a part of the system that many people leave out when planning the budget, because "the water from the public mains is clean anyway". The reality is different - even drinking water meeting all standards contains microscopic particles of sand, rust from older pipework in the public network, or scale deposits that loosen over time. These particles gradually accumulate in a closed heating circuit, clogging narrow passages in thermostatic valves and manifolds, and in an extreme case can block the circulation pump.

A cyclonic sludge trap filter works on a simple physical principle - the water is spun inside the filter body, heavier particles sink into the bottom collection cup by centrifugal force, from where they can simply be drained without needing to dismantle the whole filter. Compared to a classic mesh filter, it has the advantage of clogging much more slowly, and maintenance is quicker - you just need to open the drain valve at the bottom occasionally.

Cyclonic sludge trap filter 4" - 1/2"F - we recommend placing it right at the water inlet to the system, before the first manifold or boiler, to protect the whole installation downstream. Price from 102.34 EUR.

Yes, this is one of the more expensive components in the whole set-up, but you should think of it as insurance - its cost is negligible compared to the cost of replacing a clogged manifold or circulation pump a few years down the line. In practice we have found it useful to place the filter right before the main shut-off valve, so it can easily be isolated from the rest of the system during servicing without needing to drain the whole system.

Price comparison of the individual components in the set-up

When putting together a set-up for the first time, it is useful to have an overview of which items make up the biggest part of the budget. The following chart compares the prices of five typical components we have covered so far in this article and discuss further below.

The comparison clearly shows that the filter is the single most expensive item, but as a rule only one is bought for the whole system. Compression fittings and clips, on the other hand, are cheap piece by piece, but a larger installation needs dozens of them, so their combined cost in the budget grows in proportion to the size of the system. When planning your budget, therefore, do not plan just by unit price, but by the actual quantity you need for the given installation.

Fixing and securing the pipe - an underestimated but important detail

Insufficient or incorrectly spaced pipe fixing is one of the most common causes of later problems - not just aesthetic ones (sagging or rattling pipe), but functional ones too. Poorly fixed pipe can gradually shift under thermal expansion (and both copper and plastic pipe genuinely expand and contract with temperature changes), which puts stress on joints and in an extreme case can loosen a compression fitting.

The recommended spacing of clips for horizontally routed pipe is commonly around 1-1.2 metres for a 15-22 mm diameter, and somewhat tighter for vertical risers because of the weight of the filled pipe. Clips should also allow slight movement (so-called sliding fixing) in places where you expect thermal dilatation of longer straight sections, with fixed fixing only at fixed points along the route.

HS 45mm clips for machine pipe fixing, joined by wire into a strip - a practical pack joined by wire into a strip, suitable for fast machine installation when fitting a large number of clips at once. Price from 21.77 EUR.

In larger renovations, where a hundred metres or more of pipe needs to be fixed, this type of pack (joined into a strip) really pays off - the installer does not have to reach for individual pieces, which saves real time on site during series installation.

Manifolds - the heart of multi-circuit systems

As soon as you have more than one separate circuit in the house (for example a combination of radiators in one part of the house and underfloor heating in another, or several independently controlled zones), you need a manifold. Its job is to distribute water from the main supply into individual branches, while also allowing them to be shut off or regulated individually - for example when you want to shut down just one branch for the summer without affecting the rest of the system.

When choosing a manifold, it is essential to correctly estimate the number of circuits you will actually need - not just today, but also with a view to possible future expansion (for example an extension, or converting the attic). Buying a larger manifold afterwards is far more complicated than planning for one or two spare branches right from the start.

4-circuit manifold with valve, 15 x 15 x 15 x 15 - suitable for a typical family house with four independently regulated branches, each with its own shut-off valve. Price from 41.69 EUR.

When installing the manifold, also do not forget about its accessibility - it should be positioned so that the individual valves remain comfortably reachable even years later, for example for venting or seasonal adjustment of branches. A manifold walled in or cast in concrete without an inspection hatch is unfortunately still a common mistake we see even in new builds.

Radiator valves and temperature control

The last, but equally important component is control on the side of the individual appliances - most commonly radiator valves. These allow you to set (manually or via a thermostatic head) the flow into a particular radiator, and thus its resulting temperature, independently of the rest of the system.

When choosing a valve, it is important to distinguish between a straight and an angled version - this depends on how the pipe is routed to the radiator (from below, from the side, straight, or at a right angle). Fitting the wrong type of valve is a fairly common mistake in DIY installation, which can be fixed, but means additional elbows or reworking the last part of the pipe run.

Straight thermostatic radiator control valve, EK x 1/2" - suitable for a straight connection of the pipe with no change of direction, ready for fitting a thermostatic head. Price from 8.58 EUR.

If you are not sure which version you need, the most reliable approach is to measure and photograph the existing pipe connection to the radiator before ordering - or simply ask us directly through the form at the end of this article.

Common diameters vs. typical use - a quick overview

To give you a quick overview when ordering components, we have summarised the typical pipe diameters and their usual use, discussed above, into a simple graphical overview.

Recommended step-by-step approach to choosing components

To summarise the whole procedure into practical steps we recommend following when planning a set of HEPWORTH components, it looks like this:

The most common mistakes when choosing HEPWORTH components

Over years of experience selling and advising on HEPWORTH systems, we have identified a list of the most recurring mistakes:

Underestimating the pipe diameter - especially when adding another radiator to an existing branch, without recalculating whether the original diameter can still handle the increased flow.
Missing filtration - common especially in DIY renovations, where money is saved on an "invisible" component that only shows its effect after months of operation.
Insufficient number of clips or their incorrect spacing, leading to sagging pipe and unnecessary stress on joints.
Undersized manifold without a spare branch - the problem only shows up during a future expansion of the system, when you find out that you don't just need to buy more components, but replace the whole manifold.
Confusing straight and angled valves - a small mistake that requires additional elbows or reworking the last part of the pipe run right before the radiator.
A damaged pipe cut when fitting a compression fitting - even a small scratch or uneven cut can cause a slowly leaking joint that only shows up after a few weeks or months, by which point it is harder to trace.

Most of these mistakes can be avoided with one simple step - before ordering, write down an exact list of branches, their lengths, the number of appliances on each branch, and the planned number of circuits on the manifold. This simple "paper" overview will save you time and money during the installation itself.

When it is worth consulting an expert

The HEPWORTH system is designed so that, with a bit of skill, even a competent DIY enthusiast can install it - especially simpler branches with a few radiators. For larger or more complicated installations (several independent zones, a combination of radiators and underfloor heating, connecting to an existing older system), however, it is worth discussing the component set-up in advance, before ordering.

The reason is simple - adjusting the pipe diameter afterwards, or replacing an undersized manifold once part of the system is already walled in or cast into the floor, is far more expensive and difficult than correct planning at the start. If you are not sure, write to us through the form below - we are happy to help you put together a specific set-up based on your floor plan or a description of your situation.

Frequently Asked Questions

What pipe diameter should I use for a typical family house?

In most family houses, the main distribution is handled in a diameter of 22 or 28 mm, with end connections to individual radiators then at 15 mm. However, the exact diameter should be based on a calculation of heat output and route length, not a blanket estimate - if in doubt, it is better to choose a pipe one size larger than to deal with insufficient flow later.

Do I have to include a filter in the system if I have good water from the public mains?

Yes, we recommend it. Even good-quality drinking water contains microscopic particles that gradually accumulate in a closed circuit. A filter is a one-off investment that protects all the following, much more expensive components (manifold, valves, possibly the circulation pump) from clogging.

Can a compression fitting be reused, for example during a service job?

Yes, that is one of the main advantages of this type of joint over soldering or pressing - the fitting can be disassembled and reassembled. On reuse, however, we recommend checking the condition of the sealing ring and, if in doubt, replacing it with a new one to prevent a later leak.

How do I know whether I need a straight or an angled radiator valve?

This is determined by the direction the pipe runs to the radiator. If the pipe runs directly in line with the radiator connection, you need a straight valve. If the pipe changes direction (for example coming from below while the radiator is connected from the side), you need the angled version. If unsure, the most reliable approach is to photograph the existing connection and send it to us for assessment.

How many circuits should a manifold have if I am planning a future extension or converting the attic?

We recommend adding at least one, ideally two, spare branches to the number of circuits you currently need. Replacing a manifold with a larger one afterwards, once part of the system is already finished and cast in place, is significantly more complicated and expensive than slightly oversizing it right from the start.

What should I do if I am not sure about the whole set of components?

The simplest thing is to write to us with an exact description of your situation (number of radiators, possibly a floor plan, branch lengths) through the contact form at the end of this article or directly when ordering. We are happy to help you put together a complete list of components so that you don't forget anything, while also not overbuying.

Have a question on this topic?

Can't decide, or dealing with a specific situation in your household? Write to us - we're happy to help.