Ultra-high-pressure unit guide
WOMA EcoMaster MK4: the complete guide to the 3,000 bar unit
Everything you need to know about the EcoMaster MK4, explained by people who run it on site: pressure and flow for each version, the jobs it handles, when you need a robot, how it is towed, and how to buy, rent or service one.
- 3,000bar maximum pressure
- 40l/min maximum flow
- 175kW Volvo engine
- 2,500kg on a trailer
Hidrodem technical team · Updated
Explore the machineWhat is the WOMA EcoMaster MK4?
The EcoMaster MK4 is a mobile ultra-high-pressure unit from WOMA (Kärcher group) built on a twin-axle trailer. With 190MX or 250MX pumps and a 175 kW Volvo diesel engine, it runs at 2,200, 2,750 or 3,000 bar and up to 40 l/min for hydrodemolition, surface preparation, hull stripping and cutting.
- Successor to the EcoMaster MK3, with the new MX pump generation: longer service life and longer maintenance intervals.
- Two pumps, three pressures: the 250MX delivers more flow; the 190MX less flow at the same pressure.
- Hidrodem sells and rents it directly, with or without an operator, and services it.
What sets it apart from other ultra-high-pressure units?
The MK4 packs a 3,000 bar pump, a Stage V engine and a control system that keeps the machine unpressurised until the gun is triggered into a unit under 2 m tall and about 4.4 m long. It is built to travel from site to site by road and work in tough conditions without losing time to maintenance.
MX pumps
WOMA's new pump generation: longer service life, longer maintenance intervals and, according to the manufacturer, significant time and cost savings.
Under 2 m tall
Fits into buildings, under bridges and through site access points where a taller unit will not go.
Aluminium noise hood
Cuts noise on site and protects the unit.
Unpressurised at rest
The system has no pressure until the operator triggers the gun: safer, and less wear.
WOMATIC 4
A clear control system with operating status monitoring, pressure and speed control and unpressurised circulation.
Radio remote ready
Pre-equipped for radio remote control, so the unit can be operated from the work point.
What is inside the EcoMaster MK4?
Under the aluminium hood sit the MX-series ultra-high-pressure pump, the Volvo diesel engine, the fuel and water tanks, the WOMATIC 4 control cabinet and a base frame that does not pass on vibration. Everything is modular and within reach, so servicing is quick.
- 1190MX or 250MX pumpThe heart of the machine, producing up to 3,000 bar. The 250MX moves more water (up to 40 l/min), the 190MX less (up to 33.5 l/min).
- 2Volvo diesel engine · 175 kWOff-road engine in EU Stage V (with diesel particulate filter and SCR) or EU Stage 3A / US EPA Tier 3 versions.
- 3WOMATIC 4 controlMonitors the unit, controls pressure and engine speed and lets water circulate without pressure when not working.
- 4Fuel tank · approx. 240 lRange for long shifts far from a fuel station.
- 5Water tank · approx. 120 lThe pump's buffer tank. At 40 l/min it would empty in about 3 minutes, so the unit needs a continuous water supply.
- 6Frame and twin-axle trailerVibration-free base frame, extra storage space and road approval as a trailer up to 100 km/h.
Keep scrolling: the hood opens and the machine comes apart.
What does a 3,000 bar jet do to concrete?
At 3,000 bar the water leaves the nozzle at over 700 m/s. It breaks deteriorated concrete through micro-fractures and removes it with no vibration or impact, while the reinforcement stays intact, clean and ready for new concrete. That is selective hydrodemolition: only the bad concrete goes.
The speed comes from the physics of the jet (v = √(2p/ρ)): at 3,000 bar, around 775 m/s before losses. That energy is focused on a few millimetres and breaks the weak concrete paste before the sound concrete, which is why hydrodemolition is selective.
With WOMA high-pressure guns and pressures up to 3,000 bar, selective concrete removal is possible. Combined with the WOMA TD3000 SCS, the MK4 uncovers steel reinforcement and rebar; with a hand lance or the Magnet Lizard, it strips multi-layer paints and antifouling coatings from ship hulls.
Compared with a jackhammer or a scarifier, water does not transmit vibration to the structure, leaves no micro-cracks in the concrete that stays, does not bend or cut the bars and creates far less dust. That is why it is specified on bridges, dams and buildings in use, where what is kept must not be damaged.
Which MK4 version do you need?
Pick the pump, engine stage and pressure: the configurator shows the official flow rate, the hydraulic power and the reaction force with the full flow through one nozzle. At full flow every version exceeds 250 N, so it also tells you how much flow a single nozzle can take for hand-held work.
Official WOMA flow rates. Power = pressure × flow / 600. Reaction force calculated with the full flow through a single nozzle and no losses (F = Q·√(2ρp)), so it is a maximum: with rotating tools, several nozzles or lower engine speed the force drops. 150 N and 250 N thresholds from section 20-1 of the Norwegian Regulations concerning the Performance of Work, the Safe Work Australia guide and the Water Jetting Association code of practice.
What pressure, flow and weight does the EcoMaster MK4 have?
The MK4 runs at 2,200, 2,750 or 3,000 bar with a Stage V engine (2,000, 2,500 or 3,000 bar with Stage 3A). The 250MX delivers 40, 31.5 or 24.5 l/min and the 190MX 33.5, 26.5 or 20.5 l/min. It weighs about 2,500 kg and measures 4,438 × 2,245 × 2,000 mm.
Maximum flow by pump and pressure
| Pressure (Stage V) | Pressure (Stage 3A) | 190MX | 250MX |
|---|---|---|---|
| 2,200 bar | 2,000 bar | 33.5 l/min | 40 l/min |
| 2,750 bar | 2,500 bar | 26.5 l/min | 31.5 l/min |
| 3,000 bar | 3,000 bar | 20.5 l/min | 24.5 l/min |
General data
- Pumps
- 190MX or 250MX (WOMA MX series)
- Engine
- Volvo off-road diesel, max. 175 kW
- Emissions
- EU Stage V (DPF/SCR) or EU Stage 3A / US EPA Tier 3
- Control
- WOMATIC 4
- Fuel tank
- approx. 240 l
- Water tank
- approx. 120 l
- Weight
- approx. 2,500 kg (Stage V) · approx. 2,400 kg (Stage 3A)
- Dimensions (L × W × H)
- 4,438 × 2,245 × 2,000 mm
- Chassis
- Twin-axle trailer, approved up to 100 km/h
Configuration options
- Control interface for the EX-i water tool
- Additional remote control connection: HP release station with emergency stop (Advanced and Expert versions) or external emergency stop
- Maintain engine speed after high pressure off
- High pressure on/off from the control cabinet
- Telematics (with a telematics contract)
- Spark arrester in the exhaust (not for stages 4 and 5)
- Air shut-off valve (Chalwyn)
- Crane lugs
- Weather protection covers
Why does pressure differ between Stage V and Stage 3A?
WOMA's 2026 catalogue gives different pressure steps depending on the engine: with Stage V the MK4 runs at 2,200, 2,750 and 3,000 bar; with Stage 3A, at 2,000, 2,500 and 3,000 bar, with the same flow rate at each step. Stage V is required in the European Union for new non-road mobile machinery; Stage 3A / Tier 3 is offered for markets outside the EU.
190MX or 250MX?
At the same pressure, the 250MX gives around 19 % more flow than the 190MX (40 versus 33.5 l/min at 2,200 bar). More flow means more output on hydrodemolition and large surfaces, but also more reaction force at the gun: for hand work at 3,000 bar, splitting the flow or working with a robot is usually the better fit.
What changed from the MK3 to the MK4?
| EcoMaster MK3 | EcoMaster MK4 | |
|---|---|---|
| Pumps | M series (190M / 250M) | New MX series (190MX / 250MX) |
| Service life and maintenance intervals | Baseline | Longer, according to WOMA |
| Design | Unit with noise protection hood | Modular, with better access to service parts |
| Frame and storage | — | Vibration-free base frame and more storage space |
What jobs is the EcoMaster MK4 used for?
WOMA positions it for concrete repair, surface preparation, ship paint stripping and industrial cutting. At Hidrodem we use it mainly for hydrodemolition: bridge decks and edges, dams, ports and industry, wherever damaged concrete has to come off without touching the reinforcement.
Selective hydrodemolition
Removing damaged concrete from bridge decks, parapets and abutments, leaving clean, crack-free reinforcement ready for new concrete.
Exposing reinforcement
Uncovering reinforcement and rebar without cutting or bending it, with a lance or the TD3000 SCS.
Surface preparation
Removing laitance, paint and coatings to achieve the roughness that mortars and linings need.
Stripping and cutting
Multi-layer paint and antifouling on hulls with a lance or Magnet Lizard; cutting materials in industry.
Photos from Hidrodem projects.
What does safe work at 3,000 bar require?
Trained operators, full PPE, a cordoned-off work zone and the right tool for the reaction force. The MK4 helps: it has no pressure while the gun is released and accepts an external emergency stop and an HP release station. Above 250 N, the hand-held gun is replaced by a robot or manipulator.
Machine standard
High-pressure water jet machines are covered by EN 1829-1 (safety requirements for machines).
Training
Operators must be trained on the unit and on jet hazards: a high-pressure water injection injury is a medical emergency even when it looks minor.
PPE
Helmet with visor, hearing protection, jet-resistant clothing and gloves, and boots with metatarsal protection.
Cordoned zone
A marked perimeter with no access while under pressure; the distance depends on pressure and tool.
Reaction force
Up to 150 N, hand-held; 150 to 250 N, braced against the body; above that, mechanical control. The configurator on this page calculates it for every version.
Maintenance
The MK4's modular design keeps service parts within reach. Following the manufacturer's intervals is what keeps pressure stable and the machine safe.
How do you buy, rent or service an EcoMaster MK4?
Hidrodem sells and rents the EcoMaster MK4 directly, with or without an operator, services it and supplies spare parts. And if what you need is the job done, we carry out your hydrodemolition or surface preparation with our own equipment and crews. Price on request, depending on version and options.
Project quote
Hydrodemolition, surface preparation or stripping carried out by Hidrodem, with our own equipment and operators.
Buy or rent
A new EcoMaster MK4 or a rental unit, with or without an operator, in the version that best fits your work.
EcoMaster MK4 frequently asked questions
Performance
What is the maximum pressure of the EcoMaster MK4?
Up to 3,000 bar on every version. With a Stage V engine the steps are 2,200, 2,750 and 3,000 bar; with Stage 3A, 2,000, 2,500 and 3,000 bar.
What flow rate does the MK4 deliver?
The 250MX gives 40 l/min at 2,200 bar, 31.5 at 2,750 and 24.5 at 3,000. The 190MX gives 33.5, 26.5 and 20.5 l/min at the same steps.
How powerful is it?
The Volvo diesel engine delivers up to 175 kW. Hydraulic power in the water reaches about 147 kW with the 250MX at 2,200 bar (pressure × flow / 600).
What is hydraulic power and why does it matter?
It is the energy carried by the water: pressure times flow divided by 600, in kW. More hydraulic power means more concrete or coating removed per hour. The 250MX at 2,200 bar reaches about 147 kW.
What is the difference between the 190MX and the 250MX?
Flow: the 250MX moves more water at the same pressure. More flow means more output, but also more reaction force at the gun.
What is the MX pump generation?
It is the evolution of WOMA's pumps introduced with the MK4. According to the manufacturer, it extends service life and maintenance intervals, which lowers the cost per hour.
Engine and emissions
Which engine does the EcoMaster MK4 use?
An off-road Volvo diesel engine of up to 175 kW, in an EU Stage V version with particulate filter and SCR, or an EU Stage 3A / US EPA Tier 3 version.
Can I use the Stage 3A version in the EU?
New non-road mobile machinery placed on the EU market must meet Stage V. Stage 3A / Tier 3 is offered for markets where it is allowed; ask us about your case.
How much fuel and water does it carry?
About 240 l of diesel and a water tank of about 120 l. The water tank is a buffer: a continuous water supply is needed while working.
Towing and transport
How much does the MK4 weigh and measure?
About 2,500 kg in the Stage V version (2,400 kg in Stage 3A) and 4,438 × 2,245 × 2,000 mm, under 2 m tall.
What driving licence do I need to tow it?
It is a trailer over 750 kg, so in the EU it is normally towed on a BE licence (a B96 only covers combinations up to 4,250 kg). In Spain the trailer also needs its own registration, roadworthiness test (ITV) and insurance.
How fast can it be towed?
WOMA approves it as a trailer up to 100 km/h, but national limits apply: in Spain, for example, a car with a trailer is limited to 90 km/h on motorways and 80 km/h on other roads.
Can it be lifted by crane?
Yes, if ordered with the crane lug option.
Applications
Is it suitable for hydrodemolition?
Yes. With pressures up to 3,000 bar it removes damaged concrete selectively and leaves the reinforcement clean. For large areas it is combined with a robot.
What are the advantages of hydrodemolition over a jackhammer?
No vibration, no micro-cracks in the sound concrete, the reinforcement is preserved and there is less dust. The result is a rough, clean surface that bonds better with new concrete.
And for surface preparation or hull stripping?
Yes: it removes laitance, paint and coatings, and with a hand lance or Magnet Lizard it strips multi-layer paints and antifouling from hulls.
Can it cut materials?
WOMA also positions it for cutting different materials in industry, with the right tool and nozzle.
Safety
Can you work by hand at 3,000 bar?
It depends on the flow per nozzle. With the full flow through a single nozzle every version exceeds 250 N and mechanical control is needed. At 3,000 bar a hand-held nozzle takes about 19 l/min braced against the body; the configurator calculates it for every version.
What happens if I let go of the gun?
The MK4 is unpressurised while the gun is not triggered. It also accepts an external emergency stop and an HP release station.
What training does the operator need?
Training on the unit and on high-pressure water jet hazards, plus full PPE. If you do not have a trained operator, rent it with a Hidrodem operator.
Buying, renting and service
How much does an EcoMaster MK4 cost?
The price depends on the pump, engine stage and options (telematics, remote control, crane lugs…). Send us the configuration and we will send you a firm price.
Can the MK4 be rented?
Yes. Hidrodem rents it with or without an operator. Tell us about the job and we will propose the terms.
Do you provide maintenance and spare parts?
Yes: maintenance, repairs and spare parts for the EcoMaster MK4, carried out by technicians who work with it on site.
Does the MK4 replace the MK3?
Yes, it is its direct successor, with the new MX pump series instead of the M series and a more modular, service-friendly design.