Vaillant quick installation set L20 for ecoCOMPACT/auroCOMPACT

Product detailed description

Quick-assembly kit L20 for Vaillant ecoCOMPACT and auroCOMPACT

The L20 quick-assembly kit is original supplementary Vaillant hydraulic accessory for floor-standing condensing boilers with an integrated storage tank from the ecoCOMPACT and auroCOMPACT ranges. It contains a second high-efficiency circulation pump with hydraulic accessories, enabling connection of a second direct (unmixed) heating circuit with the same water temperature as the first circuit handled by the basic L10 kit.

Unlike the L11 kit, which adds a mixing circuit with its own independently controlled (usually lower) temperature via a three-way valve with servo drive, the L20 kit addresses a simpler case – a second heating branch without the need for separate temperature control, for example as a separate circuit for another part of the building (an extension, garage, separate wing of the house) or as a way to hydraulically split a larger radiator system into two independently controllable (switchable on/off) branches while maintaining the same water temperature.

Technical characteristics

• Intended for: Vaillant ecoCOMPACT (VSC, VCC) and auroCOMPACT (VSC D), supplementary kit to the basic L10
• Function: hydraulic solution for a second direct (unmixed) heating circuit with the same temperature as the first circuit
• Main components: high-efficiency electronically controlled class A circulation pump, hydraulic accessories, connection fittings, mounting material
• Control: the pump of the second circuit is controlled by the boiler's control unit, switching independently of the first circuit according to the needs of the given branch (e.g. a separate time program or room thermostat)
• Installation: directly into the boiler casing together with the L10 kit, without the need for an external distributor
• Typical use: a second separate heating branch with the same temperature as the first circuit, for example a separate wing of the house, an extension, or splitting a larger system into two independently switchable branches
• Max. operating temperature: up to 110 °C
• Fitting material: brass/steel depending on the specific component, resistant to common heating water parameters

Why choose L20 instead of L11

The choice between the supplementary kits L11 and L20 depends on whether the second heating circuit in a given building needs its own independently controlled water temperature different from the first circuit, or whether the same temperature is sufficient. If the second circuit is, for example, another radiator branch with the same type and sizing of heating elements as the first circuit, a mixing valve is not needed and the simpler, more cost-effective and technically less demanding solution is precisely the L20 kit – in this case both circuits receive water at the same temperature from the boiler, differing only in that each has its own circulation pump and can be switched on and off independently of each other (for example according to a different time schedule, or if one part of the building is temporarily not used).

The L20 kit is thus a suitable choice where the main reason for splitting the system into two circuits is not a different temperature requirement, but rather the need for independent control (switching on/off) or hydraulic division of a larger distribution system into more manageable branches in terms of pressure losses.

Installation

The kit must be installed exclusively by an authorised technician qualified to install gas and heating appliances, always in combination with the basic L10 kit already installed (or being installed simultaneously) in the boiler casing. After connecting the second circuit, its switching mode is set in the boiler's control unit (for example a separate time program or linkage to a room thermostat of the second branch) and a functional test of the correct operation of both pumps independently of each other is performed.

When planning, we recommend considering in advance whether the combination L10 + L20 (same temperature for both circuits) or L10 + L11 (independently controlled temperature of the second circuit) is more suitable for the given building, as this choice depends on the specific hydraulic scheme and type of heating elements in the individual zones of the building.

In case of doubt, we recommend consulting this choice directly with the heating supplier or system designer before ordering a specific supplementary kit.

Compatibility

The L20 kit is intended exclusively as a supplement to the basic L10 kit for Vaillant ecoCOMPACT (VSC, VCC) and auroCOMPACT (VSC D) boilers – on its own, without the L10 kit, it is not functional, since L10 handles the basic hydraulic separation of the boiler circuit (low-loss header) to which L20 connects. The kit is not interchangeable with hydraulic accessories of other Vaillant boiler ranges with a different design of built-in hydraulic components, nor with the supplementary L11 kit, which addresses a different function (mixing circuit).

When ordering, we therefore always recommend specifying exactly which type of supplementary kit (L11 or L20) the given project requires, and also stating the boiler model to which the kit is to be installed.

Maintenance and care

As part of the regular annual boiler service inspection, we recommend checking:

• smooth operation and noise level of the second circuit pump,
• tightness of the kit's connection fittings,
• functionality of the independent switching of the second circuit (for example according to a time program or room thermostat),
• the overall condition and any deposits in the pump's circulation part during professional disassembly during servicing.

The electronically controlled class A pump requires no lubrication or other manual maintenance during normal operation; however, the quality of the heating water in the system according to the recommendations of the VDI 2035 directive is important.

We also recommend occasionally visually comparing the operating parameters of both pumps (L10 and L20) with each other, as a significant difference in noise or temperature between them can be an early sign of one of them starting to wear out.

This simple comparative check takes the service technician no more than a few minutes during the annual inspection, but can provide early warning of a developing problem before it manifests as a heating failure in one of the zones.

Why choose an original Vaillant part

The L20 kit is designed to work precisely together with the basic L10 kit and with the boiler's control electronics, which enables independent switching of both circuits. An original part guarantees correct mechanical and functional compatibility without the need for additional modifications, which is not always guaranteed when assembling an equivalent solution from components of various manufacturers and can lead to unnecessary complications during system commissioning.

The place of the L20 kit in the modular concept of hydraulic accessories

Hydraulic accessories for ecoCOMPACT and auroCOMPACT are designed as a modular system of three mutually combinable kits – the basic L10 and two supplementary variants L11 and L20 – covering the most common hydraulic configurations of family houses without the need for an individual design of an external distributor. The L20 kit is the simpler of the two supplementary variants, as it does not address temperature control of the second circuit, only its hydraulic separation and independent switching, which makes it technically simpler and more reliable where the same water temperature for both circuits is sufficient. Where the building's hydraulic scheme allows it (i.e. where both circuits can operate with the same water temperature), L20 represents a simpler and more reliable solution with fewer moving components than L11 with its three-way valve and servo drive.

This simplicity is also reflected in lower service inspection requirements, since the L20 kit does not contain a more mechanically demanding element such as the servo drive of the mixing valve in the L11 kit.

Typical connection example

A common example of using the L20 kit is a family house with two wings or floors heated by the same type of radiators with similar sizing, where the investor or designer wants the option to independently control (for example according to a different time schedule for occupying the individual parts of the building, or for easier shutdown of one part during a long absence) two separate branches without needing a different water temperature. Another typical case is an extension or auxiliary building (for example a workshop, a heated garage) connected to the same boiler as the main building, where the same heating water temperature is sufficient, but it is practical to have the option to independently switch off this branch when the space is not in use.

In both cases, the pump of the L20 kit operates independently of the pump of the basic L10 kit, allowing one branch to run even when the other is switched off, without any mutual influence on temperature or pressure between the two circuits.