Vaillant refrigerant pipe 3/8" (9.52 mm) - 10 m, insulated

Product detailed description

Vaillant refrigerant piping 3/8" - 10 m, insulated

This insulated copper refrigerant piping with a diameter of 3/8" (9.52 mm) and a length of 10 metres is original Vaillant installation accessory intended for connecting the outdoor and indoor units of climaVAIR air conditioners (both pro and multi). The 3/8" diameter is one of the most universal sizes available in refrigerant piping - the manufacturer specifies it in the installation documentation either as the gas (suction) line for lower and medium power classes of indoor units, or as the liquid line for more powerful sets and multisplit configurations - the exact assignment always depends on the specific outdoor/indoor unit pairing.

The pipe is supplied with factory-applied thermal insulation along its entire length, which limits heat losses during operation and prevents condensation (moisture from the air) forming on the surface of the piping when routed through the interior. Thanks to the pre-insulated design, the installation company does not need to insulate the piping additionally after routing it, which shortens installation time and reduces the risk of gaps in the insulation.

Technical parameters

When is the 3/8" diameter used

The refrigerant circuit of a split air conditioner runs two pipes of different diameters between the outdoor and indoor unit - a thinner liquid line and a thicker gas (suction) line. In climaVAIR systems, the 3/8" diameter most often appears as the gas line for lower power classes of indoor units (for example models with an output range of approximately 2.0 to 3.5 kW), where the manufacturer combines it with a 1/4" liquid line. For some higher power classes or for climaVAIR multi (VAM1) multisplit sets, the 3/8" diameter may conversely be specified as the liquid line combined with a 1/2" or 5/8" gas line. Always check the exact combination of diameters for the given pair of units in the installation manual of the specific model - the manufacturer specifies it according to the power class, the length of the route and the height difference between the units.

Installation principles when working with refrigerant piping

Cut the copper pipe to the required length exclusively with a copper pipe cutter (never with a saw) - the edge must remain perpendicular and free of burrs, which would otherwise damage the seal of the flare joint. After deburring, a flare cone is created with a suitable tool and the connection is made with the flare nut on the unit's service valve, tightened with a torque wrench to exactly the prescribed torque. Insufficient tightening leads to slow refrigerant leaks that only become apparent after months of operation as a drop in performance; excessive tightening, on the other hand, can damage the flare cone itself and cause an immediate leak.

Before charging the refrigerant, the entire circuit must be purged with nitrogen to remove air and any impurities from inside the piping, followed by a pressure test, and finally the circuit is evacuated to the prescribed vacuum level - this step removes moisture that would otherwise react with the compressor oil inside the refrigerant circuit and cause corrosion or clogging of the expansion valve's capillaries. For legal reasons, these operations, as well as the actual charging/topping up of refrigerant, may only be carried out by a company holding a valid F-gas certification.

When routing the pipe, make sure to use smooth bends without kinks (which would restrict refrigerant flow and reduce performance), secure it sufficiently along its entire length (so that the pipe does not vibrate during compressor operation and stress the joints), and use watertight and insect-proof bushings through the building's outer shell. When extending the route by joining multiple packages, the insulation joint is taped over with special self-adhesive tape designed for refrigerant piping, so that the insulation remains continuous without gaps.

Frequently asked questions

Is the 3/8" diameter the gas or liquid line?

It depends on the specific model and power class of the unit - for lower climaVAIR power outputs it is usually the gas line, while for some higher outputs and multisplit sets it is the liquid line. Always check the installation manual for the given pair of units.

Is the piping already insulated?

Yes, the insulation is applied at the factory along the entire length, no need to purchase insulation separately.

Is 10 m enough for a standard installation?

For most apartment and house installations, yes. For longer routes (more floors, a more distant outdoor unit) it is necessary to join more packages or choose the 25 m variant of this diameter, which is also part of our range.

Can I install the piping myself?

Routing and securing the piping itself can be handled by an experienced DIYer, but connecting it to the refrigerant circuit, evacuating and starting up the system may, for legal reasons, only be carried out by a company holding F-gas certification.

Storage and handling before installation

Until installation, keep both ends of the piping sealed exactly as delivered by the manufacturer - this prevents moisture and dirt from entering the pipe. A contaminated inner surface of the piping can later cause clogging of the expansion valve's capillary or damage to the compressor. Store the piping in a dry place and protect the insulation from mechanical damage (abrasion, cuts).

Why choose original Vaillant piping

Complying with the manufacturer's specified diameter, pipe wall thickness and insulation quality is one of the prerequisites for maintaining the warranty on the air conditioning system and achieving the unit's declared performance and energy parameters. Incorrectly sized or poorly insulated piping can cause heat losses, surface condensation, increased noise from refrigerant flow, or even faults in the indoor unit's expansion valve.

Cutting, joining and extending the route

For routes longer than the supplied 10 m, individual packages are joined using copper connecting material (a soldered or press-fit coupling) - when soldering, the inside of the pipe must be simultaneously purged with nitrogen so that scale (copper oxides) does not form on the inner surface, which could later come loose and clog the expansion valve's capillary. The joint location is then re-insulated with self-adhesive tape so that the insulation remains continuous along the whole route. Conversely, if you need a shorter route than 10 m, simply cut off the excess with a copper pipe cutter - we recommend leaving a slight surplus for shaping bends rather than cutting to an exact length.

Leak testing and safety

After completing the installation and before permanently starting up the system, a leak test of all flare joints is carried out, for example with a foam-forming detection spray or an electronic refrigerant leak detector. A leaking joint is the most common cause of gradual refrigerant loss and a drop in the air conditioner's cooling/heating performance in the first months after installation - a properly made flare joint with the correct tightening torque is therefore just as important as choosing the correct pipe diameter.

Warranty and compatibility

This piping is a supplementary installation material for Vaillant climaVAIR systems - using piping with the correct diameter, wall thickness and insulation quality as specified by the manufacturer is one of the prerequisites for maintaining the warranty on the air conditioning unit. The piping itself is covered by the standard 2-year warranty period.

Extended FAQ

Can this piping also be used with other air conditioner brands?

Physically, this is standard ACR copper refrigerant piping with a common 3/8" diameter, also compatible with other brands using the same diameter for the given line. However, always check the prescribed diameter in the installation manual of the specific unit.

What if I accidentally cut the insulation during installation?

Minor cuts can be repaired by taping over with self-adhesive insulation tape designed for refrigerant piping; for larger damage, we recommend replacing the affected section with a new piece of sleeve insulation of the corresponding diameter.

Does the piping need any preparation before installation?

No, the piping is delivered ready for installation - degreased inside, with sealed ends. Simply cut it to the required length, create flare cones and connect it to the units.

Material and tempering of the copper pipe

This is so-called ACR copper (Air Conditioning and Refrigeration) - high-purity, low-oxygen copper, chemically clean and degreased directly at the factory to prevent contamination of the refrigerant or compressor oil. When supplied in a coil (common for packages up to 10-15 m), it is soft (annealed) copper, which can be shaped by hand into gentle bends; for tighter bends, using a pipe bender is recommended to avoid flattening the cross-section and restricting refrigerant flow. Both ends are sealed at the factory to prevent air or moisture from entering during storage and transport.

Effect of pipe diameter on system performance and operation

The diameter of the refrigerant piping directly affects the flow velocity of the refrigerant and the pressure drop along the route. Too small a diameter for a given output causes excessive pressure drop and loss of performance, while too large a diameter reduces the flow velocity to the point where the compressor oil is not carried back to the compressor sufficiently (especially in vertical rising sections), which poses a long-term risk of insufficient lubrication. That is why the manufacturer prescribes an exact diameter for each combination of power class and route length/elevation - choosing a different diameter on your own is not recommended, even for a seemingly similar unit output.

Which diameter and length of piping do I need

In this category you will find Vaillant refrigerant piping in several diameters (1/4", 3/8", 1/2", 5/8") and lengths (10 m and 25 m). This product - 3/8" in a 10-metre package - is suitable for standard apartment and house installations with a shorter route between units. For longer routes (multi-storey houses, a more distant outdoor unit), choose the 25-metre variant of the same diameter instead, to avoid unnecessary joints along the route. Don't forget to order the second line of the refrigerant circuit (opposite diameter according to the installation manual) separately - both lines are almost always purchased together, each in a different, precisely prescribed diameter.

Comparison with the 25-metre package of the same diameter

When ordering, always measure the actual length of the route between the units, including allowances for bends and passage through the building's outer shell, so that you choose a variant with sufficient length without unnecessary joints.

Delivery and packaging

The piping is delivered coiled into a compact coil placed in protective packaging that protects the insulation from abrasion during transport. Due to its compact dimensions and low package weight, this product is also suitable for delivery to a parcel locker, provided this shipping option is available for the given package size from the chosen carrier.

Detailed procedure for commissioning the circuit

After connecting both refrigerant piping lines to the service valves of the outdoor and indoor units, a nitrogen pressure test follows - the circuit is pressurised to the value prescribed by the manufacturer and left for several hours to verify that the pressure does not drop (which would indicate a leaking joint). After a successful test, the nitrogen is released and the circuit is connected to a vacuum pump, which removes air and residual moisture down to the prescribed level of deep vacuum. Only after confirming that the vacuum holds are the service valves on the outdoor unit opened and the refrigerant released into the entire circuit, including the newly installed piping.

Recyclability and the environment

Copper is a fully recyclable material - if the piping is ever replaced or shortened (for example during a renovation), take the cut-off pieces to a recycling centre or metal collection point instead of disposing of them in regular waste. The insulation material is practically never replaced separately during the piping's normal service life (decades), as it is firmly bonded to the pipe already at the factory.

Common installation mistakes and how to avoid them

Among the most common mistakes made during DIY or inexperienced installation of refrigerant piping is using the wrong type of cutter (for example a universal cutter instead of one designed specifically for copper), which leads to an uneven edge and subsequent problems when creating the flare cone. Another common mistake is insufficient or, conversely, excessive tightening of the flare nut - both extremes lead to refrigerant leaks, only with a different delay before symptoms appear. An often underestimated step is the evacuation of the circuit itself - shortening this phase to save time often results in increased moisture in the circuit and gradual degradation of the compressor oil already during the first heating or cooling season in practice.

For multi-storey installations, it is also important to account for the height difference between the units - the manufacturer states in the installation documentation the maximum allowed elevation for a given combination of route length and power class, which, if exceeded, may also require adjusting the amount of refrigerant charged. This assessment should always be carried out by a company holding F-gas certification before the piping is installed, in order to avoid additional adjustments after the installation is completed.