Vaillant high-efficiency pump with connection for ecoTEC plus 80, 100 and 120 kW

Product detailed description

High-efficiency pump with connection for Vaillant ecoTEC plus 80, 100 and 120 kW

This part is an original assembly of a high-efficiency circulation pump together with a connection fitting, designed specifically for Vaillant ecoTEC plus wall-hung condensing boilers in the highest power range – namely for models VU 806/5-5 (16.5 – 82.3 kW), VU 1006/5-5 (20.7 – 102.8 kW) and VU 1206/5-5 (24.7 – 123.4 kW at a temperature drop of 50/30 °C). These boilers are used mainly in larger residential buildings, administrative and operational buildings, industrial halls and cascade boiler rooms, where a high and reliably controllable heat output is required. The pump is a key hydraulic component of the boiler circuit – it ensures forced circulation of heating water through the boiler's heat exchanger and its subsequent distribution to the system, while the connection fitting handles the mechanical and hydraulic connection of the pump to the boiler body.

For boilers with an output of 80 to 120 kW, the volume of water flow and the demands on the pump's head are considerably higher than for common domestic boilers up to 35 kW, which is why Vaillant has developed a separate design series of pumps for this power segment with a larger flow cross-section and a reinforced connection fitting. Using a non-original or undersized pump in this segment can lead to insufficient circulation, boiler fault messages (for example due to overheating of the primary heat exchanger) or increased wear of the circulation mechanism.

Technical characteristics

• Intended for: Vaillant ecoTEC plus VU 806/5-5, VU 1006/5-5 and VU 1206/5-5 (80, 100 and 120 kW)
• Pump type: high-efficiency electronically controlled circulation pump, energy efficiency class A
• Control: continuous speed variation according to the current burner modulation and the set control mode (e.g. Δp-c or Δp-v depending on the boiler's control electronics design)
• Connection fitting: included in the delivery is a connection fitting that mechanically and hydraulically connects the pump to the heating outlet of the boiler body
• Material: pump body made of durable cast iron, circulation part (rotor, bearings) made of materials resistant to water treated according to VDI 2035 guidelines
• Electrical connection: power supply and control directly from the boiler control board (no separate external power source required)
• Max. operating water temperature: up to 110 °C
• Max. system operating pressure: up to 6 bar
• Noise level: low, electronically commutated motor without mechanical brushes
• Installation: directly on the boiler body, usually at the bottom or rear of the boiler depending on the specific model

Why this pump is essential for 80 – 120 kW boilers

ecoTEC plus boilers in the 80 to 120 kW power range are almost always connected either individually into a larger heating system with multiple heating branches, or in a cascade arrangement of up to six boilers with a total output of up to 720 kW. In both cases, sufficient and even flow through each individual boiler must be guaranteed – insufficient flow leads to a larger temperature difference between flow and return (ΔT), which increases the thermal stress on the heat exchanger and can trigger a protective boiler shutdown. This is precisely why the manufacturer supplies this pump as a separate, precisely sized part for each power stage (80, 100 and 120 kW), rather than as a universal part common to the whole range.

The pump also works directly with the boiler's control electronics – its speed changes depending on the current burner modulation, achieving an optimal ratio between the pump's electricity consumption and the thermal efficiency of the entire system. This electronic interconnection is the reason why it is recommended to use exclusively the original Vaillant pump corresponding to the given power stage for this type of boiler, since the communication protocol and control curve are set by the manufacturer specifically for this part.

Installation and hydraulic connection

Installation must be carried out exclusively by an authorised service technician with professional qualification for installing gas and heating equipment. The pump is mounted directly onto the boiler body using the supplied connection fitting, which also ensures the tightness of the joint with the rest of the heating circuit. Before installation, the system must be drained or at least depressurised in the given branch; after installation, the circuit must be vented and checked for tightness at operating pressure. In a cascade arrangement of multiple boilers, the pump of each boiler is set and tested individually, and the entire cascade is then tested as a functional unit, including hydraulic balancing of the individual branches.

We recommend that the same service order also include a check of the heating water quality (especially hardness and oxygen content) according to VDI 2035 guidelines, since improperly treated water significantly shortens the service life of both the circulation pump and the boiler's primary heat exchanger, regardless of the quality of the part itself.

In practice, this pump is most commonly installed on these occasions: during the first installation of a new ecoTEC plus boiler in the given power range, when replacing a faulty or worn-out original pump after several years of operation, or when expanding an existing boiler room with an additional boiler in a cascade arrangement. In all three cases, the same principle applies – the part must precisely match the power stage of the specific boiler body.

Compatibility

The pump with connection is intended exclusively for Vaillant ecoTEC plus wall-hung condensing boilers in the 80 – 120 kW power range, specifically models VU 806/5-5, VU 1006/5-5 and VU 1206/5-5, which are commonly installed individually, in tandem, or in a cascade of up to six units with a total output of up to 720 kW. Due to the different flow requirements of the individual power stages, this part is not interchangeable with pumps intended for lower power ranges (e.g. 48 – 65 kW), for which Vaillant supplies a separate, smaller pump type. When ordering, we always recommend verifying the exact power designation of the boiler (e.g. directly on the rating plate) to ensure correct compatibility.

Maintenance and care

High-efficiency electronic pumps of this type practically require no manual maintenance during normal operation – they have no lubrication points or mechanical components requiring regular lubrication. However, as part of the annual boiler service inspection, it is recommended to check:

• the tightness of the connection fitting and any traces of deposits at the joint,
• the noise level and smoothness of the pump's operation (unusual sounds may indicate air in the system or mechanical wear),
• the functionality of the electronic speed control in comparison with the required boiler modulation,
• the quality of the heating water and any deposits in the circulation part during professional disassembly during service.

During a prolonged system shutdown (for example outside the heating season in combined industrial applications), we recommend running the pump briefly at least once every few weeks to prevent the rotor from seizing due to deposits – in newer electronic pumps, this function is often automatically taken over by the boiler's control unit (so-called anti-blocking run).

Why choose an original Vaillant part

The original pump with connection guarantees precise hydraulic and electronic coordination with the boiler's control unit, which for boilers of this power directly affects the reliability and service life of the entire system. The part undergoes the same quality control as the boiler itself, and its use is also a condition for the manufacturer's warranty on the boiler body to be honoured in the event of a fault related to the circulation of heating water. Given the high value of the investment in a boiler of this power segment, the use of a non-original or incorrectly sized pump is clearly not recommended.

Overview of ecoTEC plus 80 – 120 kW power models

The following table serves as a guide when selecting the correct power stage of the boiler and the associated pump. Exact values for a specific boiler can always be found on its rating plate or in the technical documentation supplied by the manufacturer.

• VU 806/5-5: rated heat output at 50/30 °C approximately 16.5 – 82.3 kW, at 80/60 °C approximately 14.9 – 74.7 kW, boiler body weight approx. 68 kg
• VU 1006/5-5: rated heat output at 50/30 °C approximately 20.7 – 102.8 kW, at 80/60 °C approximately 18.7 – 93.3 kW, boiler body weight approx. 86 kg
• VU 1206/5-5: rated heat output at 50/30 °C approximately 24.7 – 123.4 kW, at 80/60 °C approximately 22.4 – 112.0 kW, boiler body weight approx. 90 kg
• All three models achieve a standardised utilisation rate of up to around 109% at partial load (30%), the burner modulation range is 20 – 100% of rated output
• The boilers can be connected in a cascade of up to six units with a total installed output of up to 720 kW – in such a case, a pump is fitted separately on each boiler in the cascade

Ordering and part identification

When ordering this pump, it is essential to know the exact type and power designation of the boiler to which it is to be installed – i.e. whether it is model 806, 1006 or 1206. This information can be found on the rating plate of the boiler body, usually on the inside of the front cover, or in the accompanying technical documentation or the installation report handed over to the investor upon completion of the work. In case of uncertainty, we recommend contacting an authorised Vaillant service or the heating supplier who carried out the installation, in order to avoid ordering the wrong variant and unnecessarily extending the service intervention.

The part is supplied as a complete installation kit, including seals and mounting material, so no additional small components need to be purchased for installation on the boiler body itself. The electrical connection to the boiler's control board is handled via a connector corresponding to the given boiler range, so the qualified technician can make the connection without any wiring modifications.