Installation of the HEPWORTH Pipe System

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What a quality installation of the HEPWORTH pipe system means

The HEPWORTH system is one of the popular plastic pipe systems that in recent years have increasingly appeared in Slovakia in heating renovations and in the construction of new family houses. The reason is simple - installation is faster than with copper, the material resists corrosion, and if the correct procedure is followed it lasts decades without problems. But that phrase "if the correct procedure is followed" is the key word of this whole article. In practice we have seen dozens of installations where the material itself was good quality, but the installation was underestimated - resulting in leaks, cracks from thermal expansion, or noise in the pipework during boiler operation.

This article is a practical guide to installing the HEPWORTH pipe system, from preparation through joining itself, fixing, filtration, all the way to the pressure test and commissioning. This is not marketing copy - the goal is for you to be able to plan the installation yourself, or to be able to check the work of an installation company and know what to ask them. Where it is natural, we recommend specific components from our range that are commonly used in HEPWORTH installation - not because we want to sell something at any cost, but because the right add-on (filter, fixing clip, manifold) can determine whether the system works trouble-free or ends up as a complaint within a year.

Preparation before installation: what to get ready in advance

The first mistake we see in pipe system installations in general does not happen during the joining of the pipes themselves, but before that - with poor route planning and insufficient material preparation. Before you start cutting and joining, you should have the following points sorted out.

An accurate drawing of the pipework route. Even though it is "just" heating and not a complex industrial system, it is worth having at least a simple sketch with the lengths of individual sections, pipe diameters, and the locations of branches, manifolds, or structural crossings marked. Without this, it is very easy to order the wrong number of fittings or an insufficient length of pipe of a particular diameter, and the installation stops halfway through the job.

Checking the quality of the incoming water. This is a point that is often underestimated with plastic pipework. Mechanical impurities in the water (sand, rust from original steel pipework, deposits from water mains) can over time damage valve seals, clog manifolds, and shorten pump lifespan. In a renovation, where a new plastic system connects to an older system, it is therefore advisable to include a sludge trap filter at the water inlet. We cover filtration in more detail in a separate chapter below.

Tool list. For a HEPWORTH installation you will need specialised tools - pipe shears for plastic pipe (not an ordinary saw, which leaves burrs and an uneven cut), a welding kit or a tool for mechanical compression joints depending on the type of system, a calibrator/chamfering tool for preparing the pipe end, a measuring tape, a marker, and a sufficient number of fixing elements. Improvising with unsuitable tools is one of the most common causes of later leaks.

Ambient temperature. Plastic pipe behaves differently at low temperatures - it becomes more brittle and harder to bend. Installation in a heated room at a temperature above 5 °C is therefore clearly recommended, especially in winter months, when renovations are often carried out in a still-unheated new build.

Installation procedure step by step

The actual installation of HEPWORTH pipework follows a logical sequence of steps that should be followed in order - skipping steps (for example, leaving the pressure test until the very end after all the pipework has been walled in) is exactly the kind of decision that comes back to bite you expensively later.

Below is a simplified diagram of the six main installation steps, as we recommend following them:

1. Route preparation and cutting pipes. Pipes are cut perpendicular to their axis using shears or a cutter designed for the given diameter, never with an angle grinder or an ordinary metal saw - this creates burrs that later prevent a tight joint.

2. Chamfering and calibrating the end. Before joining, burrs are removed from the pipe end, and depending on the type of joint the edge is either slightly chamfered, or a calibrator is used, which ensures the exact diameter for fitting the fitting.

3. Joining. Depending on the specific HEPWORTH range, joints are made either by welding (for systems designed for it), or by mechanical compression joints, which are faster and do not require electric welding equipment - we write about this difference in more detail in the next chapter.

4. Fixing the pipe. The pipe is fixed to the building structure at the recommended spacing, to prevent sagging, noise from thermal expansion, and mechanical stress on joints.

5. Pressure test. Before covering the pipework (walling in, casting into screed for underfloor heating), the system is pressurised and pressure stability is monitored for at least several hours.

6. Commissioning. After a successful test, the system is connected to the boiler, vented, and put into normal operation.

Joining pipe and mechanical joints

In practice, with the HEPWORTH system we most often encounter two types of joints - butt or socket welding (depending on diameter and material) and mechanical compression fittings, which are especially practical when connecting to existing copper or steel pipework, or where you do not want to or cannot use welding technology (for example in additional work in an already-inhabited house, where you do not want to risk heat from an open flame or welding equipment near flammable materials).

A compression fitting is a mechanical joint that is tightened with a wrench and creates a tight connection without needing heat. The advantage is that the joint is finished immediately and, if necessary, can also be disassembled and reassembled - which is invaluable for example during servicing, when you need to disconnect part of the system without having to cut the pipe. When transitioning from plastic to copper pipe (a common situation in renovation, when old copper pipework remains, for example, to the radiators), a compression fitting is precisely the most reliable solution.

Compression fitting for copper pipe - 15x1-EK - exactly the type of joint you will use when connecting a new HEPWORTH plastic run to existing copper pipe leading to radiators, without any welding or soldering. Price from 2.51 EUR.

With welding itself (where the given system range requires or allows it), it is essential to follow the exact temperature and heating time according to the pipe diameter - too short a time means a weak joint, which can loosen over time under pressure, while too long a time causes deformation of the material and narrowing of the diameter at the joint, which later worsens flow and can cause gurgling and noise. Tables with exact times and temperatures are always supplied by the manufacturer of the specific fitting range, and we recommend sticking to them strictly, not estimating "by feel" based on experience with a different system - individual plastic systems differ from each other in these parameters.

Fixing and routing pipe in the structure

Correctly fixing the pipe is one of those things that at first glance look like a detail, but in reality determine the lifespan of the whole system. Plastic pipe has significantly higher thermal expansion than metal - when heated, it lengthens noticeably more than copper or steel pipe of the same length. If the pipe is not fixed at the correct spacing and with the correct type of fixing (fixed point vs. sliding fixing), this expansion shows up as cracking, bulging between fixing points, or in a worse case as mechanical stress on joints, which over time start to leak.

As a general rule, as the pipe diameter increases, so does the required distance between individual fixings - thicker pipe is stiffer and less prone to sagging, so it tolerates a wider spacing, while thinner pipe needs to be supported more frequently. As a rough guide (varies slightly depending on the specific range and pipe wall thickness), the following fixing point spacings are commonly recommended for horizontal pipe runs:

For vertical pipe runs (risers), the spacing can be increased slightly compared to horizontal runs, since the weight of the pipe acts in the direction of the fixing rather than perpendicular to it. Conversely, in places where the pipe is routed alongside a heat source (close to the boiler, where the temperature is higher), it is recommended to tighten up the spacing instead, since thermal expansion is more pronounced there.

For fixing the pipe to the building structure, metal clips with a machine-fixing system are commonly used, supplied joined into a strip - this significantly speeds up installation, because the installer does not have to reach for individual pieces; instead, the strip simply unwinds and the clips are fitted progressively at the required spacing using a fixing tool.

HS 45mm clips for machine pipe fixing, joined by wire into a strip - significantly speed up fixing longer pipework sections; the clips are joined into a strip and fitted continuously without handling individual pieces. Price from 21.77 EUR.

Crossing structures and dilatation

Where the pipe passes through a wall, partition, or ceiling, it should be run inside a protective sleeve (for example a plastic or metal tube of a slightly larger diameter), which allows the pipe to move slightly during thermal expansion without rubbing against a sharp edge of the structure or being rigidly clamped by concrete or mortar. Casting plastic pipe permanently into the structure without a dilatation sleeve is one of the most common causes of later cracks precisely at the point where it crosses a wall.

Protecting the system: water filtration at the inlet

As mentioned in the introduction, the quality of the water entering the system significantly affects the lifespan of the whole installation - including the HEPWORTH plastic pipe itself, but especially the fittings, valves, and pump, which are more sensitive to mechanical impurities. In renovations, where a new system connects to older pipework (typically when replacing a boiler or partially renovating heating in an older house), the old pipework almost always contains a certain amount of deposits - rust, sludge, residues of sealing materials from previous repairs.

The solution is to fit a sludge trap filter directly at the system inlet, before the manifold or boiler. A cyclonic filter uses a centrifugal principle - the water spins inside the filter and heavier mechanical particles separate out into a collection cup at the bottom of the filter, from where they can be simply drained without needing to dismantle the whole filter or shut down the system for an extended time.

Cyclonic sludge trap filter 4" - 1/2"F - fitted at the system inlet, mechanically catching dirt from older pipework before it reaches the manifold, valves, or pump. Price from 102.34 EUR.

Compared to the cost of an entire renovation, investing in a quality filter may seem like a minor item, but from a prevention standpoint it is one of the cheapest measures that extends the lifespan of much more expensive components - the manifold, the thermostatic control valves, and the circulation pump itself. We recommend fitting a filter whenever a new plastic system connects to any older metal pipework, even if the water appears clean at first glance.

Manifolds, circuits and temperature control

In most HEPWORTH installations, the main pipe is split into individual circuits via a manifold - typically for underfloor heating, but the same principle is also used in more branched radiator systems with multiple branches (for example a separate branch for a floor, a separate branch for an extension, and so on). The manifold allows each circuit to be regulated individually, or even fully shut off, for example during servicing, without having to shut down the whole heating system.

4-circuit manifold with valve, 15 x 15 x 15 x 15 - suitable where you need to connect four independently regulated circuits from one main HEPWORTH pipe, for example several rooms or a combination of radiators and underfloor heating. Price from 41.69 EUR.

Beyond the manifold, at each individual radiator, thermostatic control valves are then fitted, which allow you to set and maintain the desired temperature in a particular room independently of the rest of the system. A straight thermostatic control valve is a common choice where both the supply and return run in a straight line to the radiator without needing an angled connection.

Straight thermostatic radiator control valve, EK x 1/2" - allows independent temperature control on a particular radiator connected to a HEPWORTH system, a practical addition on every manifold branch. Price from 8.58 EUR.

Below is a simplified diagram of how these components connect in a typical installation - from the water inlet through the filter, through the manifold to the individual circuits, all the way to the thermostatic control valves at the end radiators.

Pressure tests and commissioning

The pressure test is a step that in practice is unfortunately sometimes skipped or done only for show - and it is exactly this moment when problems appear later that can only be fixed at significantly higher cost (breaking out tiling, chiselling out screed for underfloor heating, and so on). The principle is simple: the system is pressurised to a value higher than the normal operating pressure (typically expressed as a multiple of the operating pressure according to the standard or the manufacturer's recommendation for the given HEPWORTH range), and this pressure is monitored for a sufficiently long time - it is commonly recommended to wait at least several hours, ideally overnight, so that any pressure drop, even a very slow one, shows up.

During the test, all accessible joints - both welded and mechanical - are also visually checked for any signs of moisture or drops of water around them. This check must be done before the pipework is covered, because after it has been walled in or cast into screed, any additional repair is significantly more complicated and expensive.

If the test passes without a pressure drop and without visible leaks, the system can be connected to the heat source, vented (with multiple circuits, one at a time, circuit by circuit, not all at once) and put into normal operation. We recommend paying extra attention to the pressure gauge on the boiler for the first few days after start-up - a slight drop in the first few days can indicate residual air in the system, which will gradually vent out, while a more significant and persistent drop should be a reason to check the joints again.

The most common installation mistakes and how to avoid them

From experience, we know that the vast majority of complaints and additional repairs on plastic pipe systems can be traced to one of a few recurring mistakes. Here is an overview of the most common ones.

Insufficient or incorrect fixing spacing. As described above, wider spacing than recommended causes the pipe to sag and increases stress on joints during thermal expansion. This mistake is also hard to spot "by eye" - the pipe can look straight and taut even with incorrect spacing, and the problem only shows up after several temperature cycles.

Missing dilatation at structural crossings. Casting the pipe permanently into concrete or mortar without a sleeve is among the most common causes of cracks at the point where it crosses a wall or ceiling.

Incorrect welding time or temperature. Too short a heating time means a weak joint, too long a time deforms the diameter of the pipe at the joint. We always recommend sticking to the exact tables from the manufacturer of the specific range, not experience from a different system.

Missing filtration when connecting to older pipework. Mechanical impurities from old pipe eventually get into the valves and pump, shortening their lifespan and causing failures that at first glance seem unrelated to the pipe installation itself.

Skipping or shortening the pressure test. A "quick" test lasting a few minutes instead of the recommended hours cannot reveal slow but real leaks that only show up after the pipework has been covered.

Incorrect manifold sizing. If more appliances are connected to a manifold circuit than it is designed for, the result is uneven heat distribution, and some rooms remain underheated even though the rest of the system works without problems.

Approximate installation budget

The exact budget for installing a HEPWORTH pipe system depends on the scope of the pipework, the number of circuits, the length of the route, and whether it is a new build or a renovation connecting to older pipework. Nevertheless, it is useful to have an idea of the approximate prices of the key components mentioned in this article - it will help you estimate the overall budget even before contacting a specific installation company.

As the chart shows, small joining materials (compression fittings, fixing clips) make up only a small item in the budget, while the filter and manifold represent a larger, but one-off investment that pays for itself over the years through the extended lifespan of other components and lower failure rates. Of course, the overall budget also needs to include the pipe itself according to metres and diameter, the work of the installation company, and possibly a boiler or circulation pump if they are being replaced at the same time.

Frequently Asked Questions

Can the HEPWORTH system be combined with existing copper pipework?

Yes, this is exactly what compression fittings are for - they create a mechanical, dismountable joint between plastic and copper pipe without any welding or soldering. This is a common solution in partial renovations, where only part of the system is being replaced.

How long should the pressure test last before covering the pipework?

We recommend at least several hours, ideally overnight, so that even a very slow pressure drop shows up, which can easily be missed in a short test lasting only a few minutes.

Is a sludge trap filter needed even for a completely new installation with no connection to old pipework?

With a completely new installation, the risk of mechanical impurities is lower, but we still recommend a filter as a preventive measure - it also protects the valves and pump from ordinary dirt that can get into the system, for example during the installation itself or when topping up water during operation.

Why does my pipe in the wall crack or make noises after a while?

The most common cause is missing dilatation at a structural crossing, or incorrect fixing spacing that does not allow the pipe to expand and contract freely with temperature. If the noises recur, we recommend checking exactly these two points.

How many circuits can a standard manifold handle in a family house?

It depends on the size of the house and the number of independently controlled zones - a 4-circuit manifold commonly covers a smaller house or a combination of several radiator branches and one underfloor heating circuit, while larger houses with more zones may need a manifold with more outlets or several manifolds.

Can I do a HEPWORTH installation myself, or is a professional company required?

A skilled DIYer can handle basic mechanical joints (compression fittings), but welding and connecting to the boiler should always be done by an experienced, trained person, since a welding mistake often only shows up after months of operation, and repairing covered pipework is significantly more expensive than a correctly done installation.

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.