The Vaillant ecoTEC Pro 28 is a wall-hung gas condensing combi for small and medium homes with one bathroom. It heats your radiators and gives you hot water on demand from the mains. It’s the middle size in Vaillant’s ecoTEC Pro range, between the Pro 24 and Pro 30. Thinking of having an ecoTEC pro 28 fitted? Take a look at our Vaillant boiler installation service.
It’s still a current model in 2026 and one of the Vaillant combis we fit most. For a typical two or three-bedroom home with a single bathroom, it’s the sensible size. You get noticeably better hot water flow than the Pro 24 in the same casing, plus an LPG version for off-grid homes.
What Are The Vaillant ecoTEC Pro 28’s Key Specs?
The ecoTEC Pro 28 gives 11.1 litres per minute of hot water and up to 25.9kW for heating, in a Quiet Mark accredited casing.
| Specification | Vaillant ecoTEC Pro 28 |
| Boiler type | Gas condensing combi, wall-hung |
| Central heating output | 5.9 to 25.9kW |
| Hot water output | 27.2kW |
| Hot water flow rate | 11.1 litres per minute (at a 35°C temperature rise) |
| ErP rating | A for heating, A for hot water |
| Dimensions (H x W x D) | 720 x 440 x 338mm |
| Weight | Approx. 38kg |
| Fuel | Natural gas, with a separate LPG version |
| Noise | Quiet Mark accredited |
| Status | Current model in Vaillant’s ecoTEC Pro range |
What Is The Vaillant ecoTEC Pro 28?
It’s the mid-sized combi in Vaillant’s mainstream ecoTEC Pro range, and the one we recommend most often within it.
The Pro range sits below the higher-spec ecoTEC plus, which was remastered in 2023, and the premium ecoTEC exclusive. In a typical semi or terraced house, the Pro 28 is the size most installers reach for. Our Vaillant ecoTEC Pro range guide compares all three outputs side by side.
The 28 in the name refers mainly to hot water.
Heating output tops out at 25.9kW, only slightly more than the Pro 24. Hot water output rises to 27.2kW, though, and the flow rate goes from 9.6 to 11.1 litres per minute. In practice you get a stronger shower and less of a drop when someone turns on another tap.
What Features Does The ecoTEC Pro 28 Have?
The headline features are a hot water pre-heat, a modulating burner, a compact casing, Quiet Mark accreditation, smart control support and frost protection.
What Does The Hot Water Pre-Heat Do?
It keeps a small amount of water hot inside the boiler, so you wait less for hot water at the tap. You can switch it off if you’d rather save the small amount of gas it uses.
How Far Does The Burner Modulate?
It adjusts heating output between 5.9kW and 25.9kW to match demand.
Running steadily at low output in mild weather wastes less gas than short bursts at full power, and it’s easier on the burner and fan.
Will It Fit In A Kitchen Cupboard?
Yes, in most cases. At 720 x 440 x 338mm and around 38kg, it sits neatly inside a standard kitchen cupboard.
The components are accessible from the front, so servicing is quick and maintenance costs stay down.
Is The ecoTEC Pro 28 Quiet?
Yes. It carries Quiet Mark accreditation, so it’s a good fit for an open-plan kitchen or a boiler cupboard next to a bedroom.
Does It Work With Smart Controls?
Yes. It works with Vaillant’s eBUS controls, including sensoHOME and sensoCOMFORT, and with the myVAILLANT app through an internet gateway.
Add an outdoor sensor to a Vaillant control and you get weather compensation, which trims the flow temperature on milder days. See our smart thermostats page for the controls we fit.
Does It Have Frost Protection?
Yes. If the boiler senses temperatures low enough to risk freezing, it fires up to protect itself. Landlords with properties that sit empty over winter will find that useful, as long as the gas and power stay on.
How Efficient Is The ecoTEC Pro 28?
It’s ErP A-rated for heating and hot water, and Vaillant quotes an efficiency of around 93%. Very little of the gas you pay for goes up the flue. Swapping out an old non-condensing boiler typically brings a clear drop in gas use.
To get the best from it, the radiators need to send water back cool enough for the boiler to condense. A lower flow temperature, balanced radiators and good controls all help.
In England, Boiler Plus rules mean a new combi must have time and temperature control plus one extra measure. That could be weather compensation, load compensation or a smart thermostat with automation and optimisation.
An annual service keeps efficiency up. A Gas Safe engineer checks the burner, heat exchanger, condensate trap, flue and gas pressure, and cleans what needs cleaning.
What Are The Pros And Cons Of The ecoTEC Pro 28?
The big pluses are 11.1 litres per minute, quiet running and a compact casing. The main drawback is that it won’t keep up with two showers at once.
Pros
- 11.1 litres per minute suits most single-bathroom homes
- A-rated for heating and hot water
- Quiet Mark accredited
- Compact enough for a kitchen cupboard
- LPG version available for off-grid homes
- Works with Vaillant smart controls and the myVAILLANT app
- Built-in frost protection
- Vaillant parts are widely available and engineers know the boiler well
Cons
- Not suited to homes with two bathrooms in regular use at the same time
- Smart controls are an extra cost
- Diverter valve wear is a known issue on older ecoTEC boilers, as on many combis, though it’s a routine repair
- Narrower modulation range than the ecoTEC plus
- Costs more than some budget brands, though running costs are similar
What Size Home Does The ecoTEC Pro 28 Suit?
It suits two and three-bedroom homes with one bathroom and up to around 12 to 14 radiators.
It handles a mixer shower comfortably. It also copes with a second tap running better than the Pro 24 does, although flow will still drop at both outlets.
Got a main bathroom plus a well-used en-suite? Look at the ecoTEC Pro 30 or a larger ecoTEC plus. Homes with two full bathrooms in regular use are often better off with a system boiler and cylinder. Our guide on how to size a combi boiler explains how we work it out.
Remember that a combi can’t deliver more than your incoming mains supply. We measure flow and pressure at the survey before recommending a size.
How Much Does An ecoTEC Pro 28 Cost To Install In 2026?
A like-for-like combi swap on natural gas typically costs £2,000 to £2,800 fitted.
The table shows guide ranges for supply and fit, including a standard flue, magnetic filter, chemical flush and basic controls.
| Type of job | Guide installed price |
| Combi to combi swap, same position (natural gas) | £2,000 to £2,800 |
| Combi swap with boiler moved or new flue route | £2,600 to £3,400 |
| System or regular boiler converted to combi | £2,900 to £3,900 |
| LPG version, combi to combi swap | £2,300 to £3,200 |
Treat these as guide figures. Prices vary with the condition of your system, gas pipe sizing, flue route, condensate route and the controls you choose.
Our article on how much a new boiler costs breaks this down further, and boilers on finance covers spreading the cost.
What Are The Best Alternatives To The ecoTEC Pro 28?
The closest alternatives are the Pro 24 for smaller homes, the Pro 30 for more hot water, and the ecoTEC plus 832 for a higher spec.
- Vaillant ecoTEC Pro 24: 9.6 litres per minute, for flats and smaller homes.
- Vaillant ecoTEC Pro 30: 12.3 litres per minute for busier single-bathroom homes.
- Vaillant ecoTEC plus 832: 13 litres per minute, a stainless steel heat exchanger and a wider modulation range.
- Other brands: our best combi boiler reviews compare Vaillant with Worcester Bosch, Ideal and Baxi.
What Are The Common Vaillant ecoTEC Pro 28 Fault Codes?
The Vaillant ecoTEC Pro 28 shows an F code on its display when something stops it working. Most point to low water pressure, a gas supply problem or poor circulation in the heating system. If your Pro 28 is more than eight years old and keeps showing codes, a new Vaillant is usually the better long-term choice than paying for repeat call-outs on an ageing boiler.
| Fault code | What it means on the ecoTEC Pro 28 | Can you check it yourself? |
| F22 | Low water pressure (dry fire protection) | Yes. Top the pressure back up to around 1 to 1.5 bar |
| F28 | The boiler failed to light on start-up | Partly. Check your gas supply and, in freezing weather, the condensate pipe |
| F29 | The flame went out while the boiler was running | Partly. Check the gas supply and the condensate pipe |
| F75 | No pressure rise detected when the pump starts | Check the pressure. Anything beyond that needs an engineer |
| F83 | No temperature change at the sensors when the burner lights | Check the pressure and bleed your radiators |
| F24 | Temperature rising too quickly, usually from poor circulation | Check the pressure and bleed your radiators |
| F20 | The safety temperature limiter has tripped (overheating) | No. This needs a Gas Safe registered engineer |
| F62 | Gas valve switch-off fault | No. This needs a Gas Safe registered engineer |
Low pressure is behind a lot of these codes, so it’s worth learning how to repressurise a boiler safely. In cold snaps, F28 and F29 are often caused by ice in the plastic drain pipe outside, and our guide to defrosting a frozen condensate pipe walks you through the fix.
An egg timer symbol isn’t a fault at all. It’s the boiler’s anti-cycling delay, which we explain in our guide to the egg timer on a Vaillant boiler. For every other code, see our full list of Vaillant boiler error codes. Never take the casing off yourself. Anything inside the boiler must be handled by a Gas Safe registered engineer.
Is The Vaillant ecoTEC Pro 28 Worth It?
Yes, for most homeowners and landlords with a small to mid-sized, single-bathroom property.
It’s A-rated and quiet, it fits in a cupboard, and our engineers know it inside out.
Choose It If
- Your home has two or three bedrooms and one bathroom
- You want a quiet boiler in a kitchen or near a bedroom
- You want the option of smart controls without changing the boiler
- You’re a landlord looking for a reliable, easy-to-service boiler
- Your home runs on LPG and you want a compact combi
Look Elsewhere If
- You have two bathrooms where showers often run at the same time
- You want the wider modulation and higher spec of the ecoTEC plus
- You need the lowest possible upfront price above everything else
- You live in a small flat where the Pro 24 would do the job
Get A Free Boiler Quote From Clever Energy Boilers
If the ecoTEC Pro 28 sounds right for your home, or you’d like a second opinion on sizing, Clever Energy Boilers can help. We carry out new boiler installations for homeowners and landlords across the North West, Yorkshire and the Midlands. Every job is handled by experienced, professional and registered installers.
When we fit your boiler, you can choose from long, market-leading warranty options through Clever Energy. You can also add a servicing plan so the annual service is taken care of.
Request your free, no-obligation boiler quote online. There’s no hard sell, just a clear fixed price.
Frequently Asked Questions
What Size Property Is The Vaillant ecoTEC Pro 28 Best Suited To?
Homes with up to three bedrooms, one bathroom and around 12 to 14 radiators. If two showers are likely to run at once, consider the Pro 30, an ecoTEC plus or a system boiler.
Can The Vaillant ecoTEC Pro 28 Run On LPG?
Yes. Vaillant makes a dedicated LPG version of the ecoTEC Pro 28, and it’s the only LPG model in the Pro range. Specify LPG when you ask for a quote, and see our LPG and oil boilers page for more.
Is The Vaillant ecoTEC Pro 28 Discontinued?
No. The ecoTEC Pro 28 is still a current Vaillant model in 2026. The 2023 relaunch of the ecoTEC plus range didn’t affect it.
How Long Does A Vaillant ecoTEC Pro 28 Last?
Many keep running past 10 years if they’re well maintained, but by around 8 years old efficiency has usually dropped and faults become more common. At that point, replacing it is often better value than paying for repairs. Annual servicing and a magnetic filter on the heating system help it run well until then.
What Happens If My ecoTEC Pro 28 Shows A Fault Code?
The display shows an F code that points to the likely cause, such as low pressure or an ignition problem. You can sort some yourself, like topping up low pressure, but others need a Gas Safe registered engineer. Our Vaillant error codes guide explains the common ones.