Product detailed description

ATTACK Pump WILO Yonos PARA RS25/6, 130 mm, replacement part for ATTACK boilers

Original replacement part – WILO Yonos PARA RS25/6 circulation pump with an installation length of 130 mm, exactly matching the pump factory-fitted in selected ranges of ATTACK boilers and manifolds. This is a direct (1:1) replacement part that requires no modification of the piping or the boiler bracket – after removing the original unit, it is installed in the same place in the same way.

WILO Yonos PARA is one of the most widespread ranges of electronically controlled circulation pumps in Europe, long proven in service practice. Choosing the original OEM part instead of a universal alternative is recommended especially where 100% conformity with the original installation and boiler production documentation is important.

Why choose a class A circulation pump

The circulation pump is among the heating system components with the longest operating time – during the season it runs practically non-stop, which is why its efficiency is key to the overall operating economy of the boiler. This pump achieves an EEI ≤ 0.20, placing it among the most economical solutions on the market for domestic and smaller commercial heating circuits.

Electronic control with automatic power adaptation (so-called auto-adapt or proportional pressure) continuously monitors the current state of the circuit – closing of thermostatic heads, flow changes during zone control – and adjusts the impeller speed accordingly. As a result, the pump does not run needlessly "at full power" when the system does not require it, which is directly reflected in the electricity bill.

Compared to a standard non-controlled pump of an older generation (for example a classic three-speed type with a power input of 40–90 W at the highest setting), at the same output this class A pump can consume as little as 3–20 W at the average operating point, which over an entire heating season represents a noticeable saving without any compromise in heating comfort.

Installation length 130 mm vs. 180 mm – why it matters

Circulation pumps for domestic heating circuits are not manufactured in one universal length – you will commonly encounter two most widespread center distances between the connection threads (so-called installation length, in German "Baulänge"): 130 mm and 180 mm. This dimension must exactly match the distance between the inlet and outlet ports on the boiler body or in the pipework into which the pump is installed – a pump of a shorter or longer installation length simply will not fit between the existing connections without modifying the piping.

How to find out which length you need:

• When replacing the original pump, measure directly the distance between the centers of both flange/threaded connections of the original pump (from the center of one thread to the center of the other).
• Check the type label of the original pump – the installation length is usually part of the type designation (e.g. "25/6-130" or "25/6-180").
• For ATTACK boilers, you can find the recommended pump type and dimension in the service documentation or the boiler's hydraulic wiring diagram, or contact our customer service with the boiler's serial number.
• Never install a pump of the wrong installation length hoping to "make it fit" by tightening the union nuts over the seal – this risks leakage, stress on the piping and damage to the threads.

The connection thread of the pump body is generally 1½" (internal, for a union nut with a gasket) in both versions, so the connection to the piping itself is the same for both lengths – only the distance between the connections differs, not the thread type.

Why choose the original OEM WILO Yonos PARA part

When replacing a circulation pump during service, you basically have a choice between an original (OEM) part as installed at the factory, and a universal alternative from another manufacturer with similar parameters. The original WILO Yonos PARA RS25/6, 130 mm part offers several advantages:

• Guaranteed match of installation length, thread and hydraulic curve with the original part installed by the ATTACK boiler manufacturer.
• Verified compatibility with the boiler's control electronics, if the pump is also connected to the signaling/control from the boiler board (e.g. blocking, PWM control).
• Preservation of the boiler warranty conditions – using a non-original part may be subject to review by the service center in certain types of boiler warranty claims.
• Long-term availability of spare parts and service directly from the WILO brand, one of the world's leading manufacturers of circulation pumps.

This part is intended primarily for service technicians carrying out warranty and post-warranty service on ATTACK boilers, and for boiler owners who prefer an original replacement part over a universal alternative.

Technical parameters

• Installation length: 130 mm
• Energy class: A (EEI ≤ 0.20)
• Power input: 3 – 45 W, automatic control (auto-adapt)
• Maximum head: 6 m
• Maximum flow rate: up to 3.5 m³/h
• Connection: 1½" internal thread, union nut
• Medium temperature range: 2 – 110 °C
• Power supply: 230 V / 50 Hz, IP44 protection
• Pump manufacturer: WILO SE (Germany), supplied as an OEM part for ATTACK s.r.o.

How to read the circulation pump type label

The type label is affixed directly to the body of the pump's electronic head and contains all the information needed for unambiguous identification when ordering a replacement. In addition to the factory type designation (e.g. RS 25/6, Yonos PARA RS25/6), you will also find the installation length there (often directly in the number after the slash or in a note below the type), the supply voltage range, maximum power input, IP protection rating, and the serial/production number of the specific unit.

If the label is already illegible (for example after years of operation in the humid environment of a boiler room), the most reliable option is to directly measure the installation length with a caliper or contact our customer service with the serial number of the ATTACK boiler itself – from this we can determine which pump was factory-installed in that boiler.

When it is time to replace the circulation pump

The circulation pump is among the components that usually do not fail suddenly, but whose performance and reliability gradually deteriorate with years of operation. Several symptoms to watch out for:

• Uneven heating – some radiators or circuits are noticeably colder than others even when the thermostatic heads are fully open, which may indicate insufficient pump delivery.
• Increased noise – buzzing, squeaking or knocking during operation that does not disappear even after thoroughly bleeding the circuit usually indicates worn bearings.
• Frequent thermal fuse trips or outages – may indicate mechanical seizure of the rotor or an electrical fault in the motor winding.
• Visible leakage at the joints or around the shaft – after years of operation the seal or gasket may wear out.
• High electricity consumption compared to the declared values – an older non-controlled pump without class A rating can consume several times more energy than a modern electronically controlled solution.

If any of these symptoms occur, we recommend replacing the pump before it fails completely, which could cause boiler overheating or a heating outage at the most inconvenient moment of the heating season.

Practical installation instructions

Replacing a circulation pump is a routine service task that an experienced heating technician or service technician can handle in under an hour if the correct procedure is followed:

1. Secure the circuit. Close the supply and return using shut-off valves (if not fitted, we recommend adding them at this opportunity – they will significantly simplify future servicing), and drain the water from the relevant section into a suitable container.
2. Remove the original pump by loosening both union nuts and taking it out of the pipe run, including the old gaskets.
3. Check the flow direction marked with an arrow on the body of the new pump – it must match the direction of heating water flow at that point in the circuit.
4. Fit new gaskets and screw in the pump, while the electronic head must remain in a horizontal position after tightening (never with the terminal box facing downward), to prevent moisture from entering the electronics.
5. Fill the circuit and bleed it thoroughly – air in the pump is the most common cause of noise and reduced performance immediately after installation.
6. Test run while monitoring the tightness of the joints, noise level, and the pump's response to changes in the circuit's heat load (e.g. by closing some of the thermostatic heads).

Leave the electrical connection to the 230 V mains to a qualified person – incorrect wiring can damage the pump's electronics and also poses a safety risk.

Maintenance and extending pump service life

Electronically controlled circulation pumps of this category are virtually maintenance-free – they contain no lubrication points or parts requiring regular service beyond routine inspection. Nevertheless, a few simple habits will significantly extend their service life and maintain the declared energy class A throughout the operating period:

• Quality of heating water. Excessive sludge, rust or air in the heating circuit is the most common cause of premature wear of the impeller and bearings of the wet-rotor motor. For older or recently commissioned systems, consider installing a dirt filter or sludge separator before the pump.
• Regular visual inspection. Once per heating season, check the tightness of the connections, the absence of corrosion traces on the pump body, and any unusual noises (buzzing, knocking) that may indicate air in the system or an incipient bearing fault.
• Short-term shutdown outside the season. If the pump does not operate for a long time (e.g. outside the heating season in systems without year-round circulation), it is recommended to briefly run it occasionally to prevent the rotor from "seizing" due to deposits after prolonged inactivity – most modern pumps handle this automatically via a built-in permanent self-test function.
• Frost protection. In unheated premises (e.g. shut-down cottages, unheated technical rooms), in case of frost risk it is necessary either to drain the circuit or to use an antifreeze mixture with declared compatibility with the pump materials.

Safety warnings

Before any intervention on the pump, always disconnect the 230 V power supply and wait until the pump body has cooled down sufficiently – heating water can reach temperatures close to 90 °C and there is a risk of burns. Electrical connection must only be carried out by a person with the appropriate electrotechnical qualification in accordance with applicable standards (STN 33 2000 and related). The pump is not intended for operation outside the declared medium temperature and pressure range stated in the technical parameters – exceeding these limits may damage the pump and endanger operational safety.

Frequently Asked Questions

Is this pump really identical to the one that was in the boiler from the factory?
Yes, this is the original WILO Yonos PARA RS25/6, 130 mm replacement part, identical to the one factory-installed in selected ranges of ATTACK boilers with the same installation length.

For which ATTACK boiler models is this part intended?
For service models of ATTACK boilers and assemblies that use the WILO Yonos PARA RS25/6 pump with a 130 mm installation length as factory equipment. We recommend verifying the exact match according to the boiler's serial number with our customer service.

Is it necessary to reset or reconfigure the boiler's control unit during replacement?
In most cases no, as this is a direct 1:1 replacement. If the pump is connected to the boiler's control board via a signal wire (PWM/0-10V), we recommend visually verifying the correct operation of the control after replacement when the boiler starts up.

What is the difference between the OT130A and the universal OT01C pump of the same length?
The class A rating, head and flow parameters are almost identical. OT130A is the original WILO part with guaranteed conformity with the factory installation, OT01C is a universal alternative suitable for a wider range of installations, including other boiler brands.

Will using a non-original pump affect the boiler warranty?
In general, using a compatible replacement with the same parameters usually does not affect the warranty of the boiler as a whole, but in the event of a fault directly related to the pump, the service center may require proof of the origin and parameters of the replacement part. An original OEM part completely eliminates this issue.

Is the part supplied with mounting material?
Yes, the package includes union nuts and gaskets needed for standard installation on the 1½" thread.

Where can I find the serial number of my ATTACK boiler needed to verify compatibility?
The serial (production) number is stated on the boiler's type label, usually on the side or rear panel of the casing, or in the warranty certificate supplied with the boiler at purchase.

Why is it important to state the boiler's serial number when ordering an OEM part?
It allows us to clearly verify whether this particular pump type and installation length was actually factory-installed in your specific boiler unit, since component suppliers may have changed over the course of production series.

Is the part also suitable for cascade connection of multiple ATTACK boilers?
Yes, provided that the individual boilers in the cascade use the same factory pump type and installation length of WILO Yonos PARA 130 mm, the part is also suitable for servicing cascade assemblies.

Overview of related circulation pumps in the ATTACK range

You will also find alternatives to this original OEM part in our range:

• ATTACK Pump Yonos PARA RS25/6 RKC, 180 mm – original OEM part of the same range, only with a longer installation length for other service ranges of ATTACK boilers.
• ATTACK Replacement part - RS 25/6 pump, 130 mm – a more economical non-original alternative of the same installation length, suitable for use outside warranty service.
• ATTACK Heating circulation pump 25/6, 130 mm, class A – a universal pump of the same length also suitable for other boiler brands.

Summary

ATTACK Pump WILO Yonos PARA RS25/6, 130 mm is an original OEM replacement part for service replacements on ATTACK boilers, guaranteeing 100% conformity with the original installation. Recommended as the first choice for both warranty and post-warranty service.

Warranty and support

We provide a warranty of 24 months from the date of dispatch from the warehouse for this product. The warranty covers manufacturing and material defects, provided the installation and operating conditions specified in the accompanying manufacturer's manual are observed. If you have any questions about selecting, compatibility, or installing the pump, do not hesitate to contact our customer service – we will gladly help identify the correct type based on your ATTACK boiler's serial number or the parameters of your heating circuit.

We recommend keeping the proof of purchase, and in case of servicing your ATTACK boiler, also stating the boiler's type designation and serial number – this will speed up any warranty claim process and future identification of replacement parts.