Vaillant refrigerant pipe 1/4" (6.35 mm) - 25 m, insulated

Product detailed description

Vaillant refrigerant pipe 1/4" - 25 m, insulated

This 25-metre variant of insulated copper refrigerant pipe with a diameter of 1/4" (6.35 mm) is an extended version of the thinnest and, at the same time, most popular diameter in Vaillant's range of installation accessories for climaVAIR air conditioning units. The 1/4" diameter is used in almost all common configurations as the liquid line of the refrigerant circuit - for both lower and medium power classes of indoor units (approximately 2.0 to 5.0 kW), where the manufacturer combines it in the installation documentation with a gas line of a larger diameter (3/8", 1/2" or 5/8" depending on the specific model).

The 25-metre package length is intended for installations with a longer run between units - larger family houses, more distant placement of the outdoor unit, or runs routed across multiple floors, where a 10-metre package (also available in our range) would not be sufficient without joining several pieces. The pipe is factory-fitted with thermal insulation along its entire length, which prevents heat loss and condensation of air moisture on its surface.

Technical parameters

When to choose the 25-metre package of 1/4" diameter

The 1/4" diameter as a liquid line is used across almost the entire climaVAIR pro range (VAIB1-020WNI to VAIB1-065WNI) as well as in climaVAIR multi multisplit systems, where a separate liquid line of this diameter is run to each indoor unit regardless of the power of that indoor unit - only the diameter of the accompanying gas line changes. For shorter runs (up to approx. 8-10 m), our 10-metre package of this diameter will suffice; for longer runs in larger family houses, multi-storey buildings, or with multiple indoor units with longer individual lines, it is worth choosing this 25-metre package directly.

For multisplit systems with multiple indoor units, you will likely need several pieces of this pipe (one for each liquid line to an individual indoor unit) - we recommend preparing an overview of the lengths of the individual lines according to the actual layout of the indoor units in the building before ordering.

Installation principles when working with refrigerant pipe

Cutting of the copper pipe must be carried out exclusively with a copper pipe cutter, so that the edge remains perpendicular and free of burrs that could damage the seal of the flare joint. After creating the flare cone, the connection is made using a flare nut on the unit's service valve, tightened with a torque wrench to the specified tightening torque. Before charging the refrigerant, the circuit is purged with nitrogen, followed by a pressure test and evacuation to the specified vacuum level - these operations, as well as the actual refrigerant charging, may for legal reasons only be carried out by a company authorised to work with F-gases.

For longer runs, pay attention to smooth bends without kinking and sufficient continuous fastening of the pipe along its entire length, so that the thinner pipe does not vibrate during compressor operation. When routing several liquid lines in parallel (multisplit systems), it is advisable to slightly separate the pipes from each other or bundle them together with the corresponding gas line of the given indoor unit, so that the individual lines belonging to different indoor units are not mixed up during installation.

Frequently asked questions

Is 25 m enough even for multiple indoor units of a multisplit system?

It depends on the actual layout of the units - for some lines, 25 m may be sufficient, while for others (a more distant indoor unit) you may need another package. We recommend preparing an overview of the lengths of the individual lines in advance.

Is the pipe already insulated?

Yes, factory-applied insulation along the entire length.

Can I also buy the shorter 10-metre package of this diameter?

Yes, our range also includes the 10-metre variant of the 1/4" diameter for shorter runs.

Can the unused part of the pipe be used for another line?

Yes, the surplus part can be cut off and used for another shorter line or kept as a reserve for future system expansion.

Storage and handling before installation

Until installation, keep both ends of the pipe sealed as delivered by the manufacturer, so that no moisture or dirt gets inside. Store the pipe in a dry place, protected from mechanical damage to the insulation - especially for the longer 25-metre coil, which takes up more storage space than the shorter 10-metre variant.

Why choose genuine Vaillant pipe

Adhering to the prescribed diameter of the liquid line, wall thickness and insulation quality according to the manufacturer is a prerequisite for maintaining the warranty on the air conditioning system and achieving the declared performance and energy parameters of the unit. An incorrectly sized liquid line can cause faults in the expansion valve of the indoor unit, since it is precisely this line that supplies refrigerant directly to the expansion element.

Cutting, joining and planning multiple lines

For multisplit systems with several liquid lines of different lengths, it is worth cutting exactly the amount needed for a given line from one 25-metre package and using the rest for another line in the same installation - this minimises both waste and the number of packages ordered. When joining pipes for runs longer than one package can provide, the joints are brazed while purging the pipe with nitrogen and are subsequently insulated with self-adhesive tape.

Leak testing and safety

After installation, all flare joints on both the liquid and gas lines are checked for tightness using a foam-forming leak detection spray or an electronic refrigerant leak detector. A leak on the liquid line is, in practice, just as serious as one on the gas line, so equal attention is paid to checking the tightness of both lines regardless of diameter.

Warranty and compatibility

The pipe is a supplementary installation material for Vaillant climaVAIR systems, covered by the standard 2-year warranty period. Using pipe that corresponds to the manufacturer's specification is a prerequisite for maintaining the warranty on the air conditioning unit as a whole.

Extended frequently asked questions

Can this pipe also be used with other air conditioning brands?

Yes, this is a standard ACR copper pipe with a common diameter of 1/4", compatible with other brands using the same liquid line diameter. Always check the prescribed diameter in the installation manual of the specific unit.

What if I accidentally cut through the insulation during installation?

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

Does the pipe need any preparation before installation?

No, it is delivered ready for installation - degreased on the 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 high-purity ACR copper, degreased on the inside directly at the factory. At this thinnest diameter in the range, the pipe is soft and easy to shape into bends even without special tools; however, for tighter radii it is still recommended to use a pipe bender to avoid flattening of the cross-section, which would have a relatively large impact on refrigerant flow on this thinnest line of the circuit.

Effect of liquid line diameter on system performance

The liquid line carries refrigerant in liquid state under high pressure to the expansion valve of the indoor unit, where the refrigerant's pressure drops and it cools before entering the evaporator. An incorrect diameter of this line (too small for the given flow rate) causes an excessive pressure drop before the expansion valve, which can negatively affect its regulation and, ultimately, the overall cooling or heating performance of the unit. For this reason, the manufacturer specifies an exact liquid line diameter for each combination of power and run length, which is not recommended to be changed even in the case of a seemingly moderate excess of run length.

Which pipe diameter and length do I need

In this category you will find Vaillant refrigerant pipe in diameters of 1/4", 3/8", 1/2" and 5/8", in lengths of 10 m and 25 m. This product - 1/4" in a 25-metre package - covers the liquid line for practically the entire range of climaVAIR pro and multi units for longer runs. Do not forget to also order the corresponding gas line of a larger diameter (3/8", 1/2" or 5/8" depending on the specific model) in the same length.

If you are planning a larger multisplit installation with multiple indoor units of different powers, we recommend consulting an installation company or our customer service before ordering, so that you order the exact number of packages and diameters corresponding to the actual layout of the units in your building.

Planning the liquid line with multiple indoor units

In multisplit systems, the 1/4" liquid line runs from the refnet distributor (or directly from the outdoor unit in a simpler single-split connection) separately to each indoor unit, unlike the main gas line of larger diameter, which may be shared by several units before the distributor. When planning the route of individual liquid lines, it is therefore advisable to take into account the actual distances from the relevant distribution point to each specific indoor unit, not just the overall distance from the outdoor unit to the building.

When cutting individual shorter lines from one long 25-metre package, mark which cut piece is intended for which indoor unit - especially when unwinding several packages of the same diameter at the same time, it is easy to mix up the order and length of the individual prepared sections.

Difference between the liquid and gas line in terms of temperature and touch

During air conditioning operation in cooling mode, the liquid line (this product) is noticeably warmer than the gas (suction) line, which, in contrast, is cold during cooling and often develops condensation on its surface without quality insulation. This is precisely why factory-applied insulation is important on both lines regardless of diameter - it prevents not only heat loss but also unwanted moisture condensation on the pipe surface, which could damage surrounding building structures or wall finishes over the long term. In heating mode, the situation is reversed - then it is the gas line that is warm and the liquid line that is cooler, which is why quality insulation of both lines remains important throughout the year, regardless of the unit's current operating mode.

Typical lifespan and care of the pipe after installation

Properly installed and insulated refrigerant pipe practically requires no regular maintenance during operation - the only recommended check is an occasional visual inspection of visible sections of the pipe (for example, where it passes through the facade) for possible damage to the insulation caused by mechanical impact, rodents or weather conditions. If damaged insulation is found, it is recommended to repair the affected section as soon as possible with self-adhesive insulation tape or by replacing the sleeve insulation, to prevent long-term moisture condensation on the exposed part of the pipe.