Vaillant electric air preheater 1500 W for recoVAIR 360/4

Product detailed description

Vaillant electric air pre-heater 1500 W for recoVAIR 360/4

The electric air pre-heater (manufacturer part number 0020180799) is a genuine accessory for the Vaillant recoVAIR VAR 360/4 heat recovery unit - the most powerful model in the recoVAIR /4 generation range, with a maximum air flow of up to 360 m³/h. It is an electric heating element (heater coil) with an output of 1,500 W, installed directly into the ductwork or into the unit's construction on the incoming fresh air side, before it enters the cross-flow counter-current heat exchanger. Its purpose is not to heat living spaces (that is the job of the home's regular heating system), but to protect the heat exchanger of the recovery unit itself against freezing at low outdoor temperatures, allowing the unit to operate reliably even during freezing winter days.

Without an air pre-heater, at very low outdoor temperatures (typically below approximately -10 to -15 °C, depending on the humidity of the extracted air and the unit's settings) condensate inside the heat exchanger could freeze, leading to partial or complete blockage, reduced airflow, and in extreme cases forced defrosting cycles, during which the unit temporarily reduces or interrupts the fresh air supply. The electric pre-heater prevents this by slightly warming the incoming cold outdoor air before it enters the exchanger, keeping the temperature within a safe range and ensuring smooth, uninterrupted operation even during the coldest periods of the year.

Technical characteristics

• Device type: electric air pre-heater (heating coil) for ductwork/unit
• Manufacturer order number: 0020180799
• Heating element output: 1,500 W
• Intended for: exclusively for the recoVAIR VAR 360/4 unit (including the "E" variant with enthalpy exchanger)
• Function: protects the heat exchanger against freezing at low outdoor temperatures, enabling year-round operation without defrosting interruptions
• Power supply: 230 V AC, connected to the recoVAIR unit's electrical system according to the installation manual
• Location: integrated into the fresh air supply duct route, before the heat exchanger
• Control: automatic, switched by the recoVAIR unit's control electronics based on measured outdoor temperature
• Compatible unit - max. air flow: VAR 360/4, max. 360 m³/h, nominal range approx. 175-277 m³/h
• Country of origin: Germany / EU (Vaillant Group)
• Warranty: 2 years

Why protecting the exchanger against freezing matters

The cross-flow counter-current heat exchanger in the recoVAIR VAR 360/4 unit achieves, according to the manufacturer's technical documentation, a heat recovery efficiency of up to approximately 85% (according to EN 13141-7 methodology), significantly reducing heat losses caused by ventilation. However, in order to maintain this high efficiency even during freezing days, the exchanger must continuously remove moisture from the warm extracted air in the form of condensate. At very low outdoor temperatures, this condensate can turn into ice in the cold part of the exchanger, gradually narrowing the exchanger's air channels and reducing airflow.

The electric pre-heater prevents exactly this phenomenon by slightly warming the incoming outdoor air, raising its temperature before it enters the exchanger, thereby reducing the risk of ice forming on the cold side of the exchanger. The unit's control electronics measure the outdoor temperature and automatically switch the pre-heater on and off as needed, so that energy is consumed only when actually necessary - i.e. when the outdoor temperature drops below a defined threshold, not continuously throughout the entire winter.

Installation and connection

The electric pre-heater is installed directly into the construction of the recoVAIR VAR 360/4 unit or into the fresh air supply duct just before the unit, exactly according to the procedure described in the manufacturer's installation manual. Connection to the unit's electrical system (230 V AC power supply and connection to the control electronics for automatic switching based on outdoor temperature) must be carried out in accordance with applicable electrotechnical standards and regulations. Since this involves work on both the air duct route and the unit's electrical installation, we recommend that installation be entrusted exclusively to a trained technician or an authorized Vaillant service partner - incorrect installation (e.g. insufficient fixing of the heating element in the airflow) could compromise operational safety or reduce the service life of other components of the unit.

It is advisable to order and install the pre-heater already during the initial installation of the recoVAIR VAR 360/4 unit, especially if the building is located in an area with typical winter temperatures below -10 °C. In milder climatic areas or where the unit is well protected, subsequent installation at a later date can also be considered, although it should be noted that working on an already installed unit can be more difficult than installation during the original setup.

Compatibility

This electric pre-heater with an output of 1,500 W is designed exclusively for the recoVAIR VAR 360/4 model (the most powerful model in the range, max. 360 m³/h), including its variant with an enthalpy heat exchanger (usually denoted by the suffix "E"). For the smaller models in the recoVAIR range - VAR 260/4 and VAR 150/4 - we offer separate pre-heaters with an output adapted to their lower air flow (1,000 W for VAR 260/4, 600 W for VAR 150/4) - it is therefore neither possible nor advisable to use a pre-heater from one model on another, since the output and mechanical dimensions of the element are sized precisely for the specific airflow of the given unit.

The pre-heater can be freely combined with the other accessories of the VAR 360/4 unit - for example the CO2 sensor VAZ CO/1 or the VAZ S4/1 controller (ventilation output control), the higher F9/G4 filtration class for polluted environments, the summer bypass motor (if the unit is equipped with one), or the self-sealing condensate siphon - all of these components address different system functions and do not exclude one another.

When is the pre-heater actually needed

We recommend considering the electric pre-heater primarily for installations in locations with regular occurrence of outdoor temperatures below -10 to -15 °C during the winter period, as well as for buildings with higher indoor air humidity (e.g. households with a pool, sauna, or a higher number of occupants per floor area), where the amount of water vapor in the exhaust air, and thus the risk of condensate forming in the exchanger, is higher. Conversely, in milder climatic areas or with lower indoor humidity, the need for a pre-heater may be lower; however, we always recommend consulting operational experience for the specific location and building with an installation company or a Vaillant service technician.

Maintenance and care

As a heating element with no moving mechanical parts, the electric pre-heater does not require any special maintenance from the user during normal operation - its switching on and off is fully controlled by the recoVAIR unit's electronics based on the measured outdoor temperature. We only recommend having technicians check the functionality and electrical connection of the pre-heater as part of the unit's regular annual service (usually carried out together with filter replacement), especially before the start of the heating season, to ensure its reliable operation during the winter months.

Since the pre-heater is part of the air duct route, we also recommend paying attention to regular replacement of the unit's inlet filters (according to the service interval indicator) - dirty filters increase airflow resistance and can indirectly affect the heat balance and efficiency of the pre-heater as well.

Why choose this particular pre-heater

This electric pre-heater is a genuine accessory directly from the manufacturer of the recoVAIR VAR 360/4 unit, developed and tested to precisely match the performance parameters and dimensions of the given unit. Compared to universal or non-original third-party pre-heater solutions, it provides assurance of correct mechanical compatibility, trouble-free communication with the unit's control electronics, and preservation of the warranty conditions for the entire controlled ventilation system with heat recovery.

Impact on acoustic comfort and smooth operation

Besides protecting against freezing, the electric pre-heater also has an indirect but noticeable impact on the acoustic comfort and smooth operation of the entire controlled ventilation system. Units without a pre-heater typically respond to the risk of exchanger freezing by temporarily reducing fan output or triggering forced defrosting cycles, during which the character of the airflow and the noise level of the unit may change. Thanks to the pre-heater, such fluctuations in operation practically do not occur, and the VAR 360/4 unit can therefore operate smoothly at the set output level even during freezing days, without unexpected changes in noise or ventilation intensity that could be perceived as disturbing in living spaces.

Recommendations for designers and installation companies

When designing a controlled ventilation system with the VAR 360/4 unit, we recommend taking the electric pre-heater into account already during the design phase of the building's electrical installation - a 230 V AC power supply must be planned to the unit's installation location (if not already part of the unit's own power supply) and the circuit protection must be correctly sized for the 1,500 W power consumption. We also recommend recording information about the installed pre-heater in the project documentation for future service technicians, so that they can verify the functionality of this component during regular annual maintenance. For buildings in more extreme climatic conditions (mountain areas, locations with long-lasting severe frosts), we recommend consulting directly with a Vaillant representative or our technical department regarding the optimal setting of the pre-heater's switching threshold temperature.

Frequently asked questions

Does the pre-heater heat the rooms?

No, its purpose is not to heat living spaces, but to protect the heat exchanger of the recoVAIR unit against freezing at low outdoor temperatures, so that the unit can operate reliably even in winter.

Which recoVAIR model is this pre-heater intended for?

Exclusively for the VAR 360/4 model (including the "E" variant with enthalpy exchanger). For the smaller VAR 260/4 and VAR 150/4 models, separate lower-output pre-heaters (1,000 W and 600 W) are available.

How is the pre-heater controlled?

Automatically, by means of the recoVAIR unit's control electronics, which measure the outdoor temperature and switch the heating element on or off as needed.

Is the pre-heater necessary in every installation?

It is not mandatory, but it is recommended especially in areas with regular frosts below -10 to -15 °C and with higher indoor air humidity, where there is a higher risk of the exchanger freezing.

Can the pre-heater be retrofitted after the unit has been installed?

Yes, this is possible, but we recommend entrusting this modification to a trained technician, since it involves work on both the air duct route and the unit's electrical installation.

What is the pre-heater's supply voltage?

The heating element is powered by 230 V AC, connected to the recoVAIR unit's electrical system according to the manufacturer's installation manual.

What warranty applies to this pre-heater?

We provide a standard 2-year warranty on the electric pre-heater, the same as for other accessories and parts for Vaillant recoVAIR units.

Approximate estimate of operating costs

Since the electric pre-heater operates only intermittently - switching on automatically when the outdoor temperature drops below a defined threshold and switching off again once the risk of exchanger freezing has passed - its actual average consumption during the heating season is significantly lower than its rated input of 1,500 W. The exact consumption depends on the climatic zone, the number of freezing days per season, and the setting of the switching threshold temperature, so it cannot be quantified uniformly for all installations. As a rough guide, in a typical Central European climate with several weeks of frost per year, this represents an additional consumption on the order of tens to low hundreds of kWh per heating season - significantly less than would correspond to continuous full-power operation of the element. We recommend consulting a more precise estimate for your specific location and building with an installation company or an HVAC designer.

Comparison of pre-heaters in the recoVAIR /4 range

The higher pre-heater output for the VAR 360/4 model corresponds to its greater maximum airflow - with a larger volume of incoming outdoor air, a more powerful heating coil is also needed in order to raise the temperature of the entire air stream to a safe level within the required time before it enters the exchanger.

Relation to other optional components of the VAR 360/4 unit

The VAR 360/4 model is the most powerful unit in the recoVAIR /4 range and is typically used in larger family homes with higher air flow requirements (according to the unit manufacturer's technical documentation, units in this range cover areas of up to approximately 290 m²). At this scale of deployment, it is worth considering additional optional components as well - for example an enthalpy heat exchanger (improves comfort by transferring, along with heat, part of the moisture into the incoming air, preventing excessive drying of the air in winter), a higher F9/G4 filtration class for households in urban or industrially burdened environments, or a self-sealing condensate siphon for maintenance-free removal of condensate from the unit. The electric pre-heater can be freely combined with all of these components, since each of them addresses a different functional area of the system.

Summary

The 1,500 W electric air pre-heater is an important addition to the Vaillant recoVAIR VAR 360/4 unit for households in areas with colder winters, protecting the heat exchanger against freezing and ensuring uninterrupted, reliable operation of the controlled ventilation with heat recovery throughout the year. As a genuine accessory directly from the manufacturer, it guarantees precise compatibility with the unit as well as preservation of the warranty conditions for the entire system. If you are unsure whether the pre-heater is necessary for your specific project, we are happy to advise you by phone or email.