Which Automatic Swing Door Operator Is Better?

 

If you've worked with automatic doors in the UK for any length of time, there's a good chance you've come across a record DFA 127.

And there's a reason for that.

The DFA 127 has been around for years. Thousands have been installed, engineers know them inside out, and the operator has built a reputation for being a solid and dependable bit of kit.

The ASSA ABLOY SW300-S comes at the same job from a different direction.

It's a newer-generation swing door operator, with considerably more emphasis on software, diagnostics, energy consumption and the ability to deal with some seriously demanding doors.

So, is the SW300-S simply a better, more modern alternative to the DFA 127?

Not necessarily.

The DFA has something you can't put on a new product's specification sheet: years of proven service in the real world.

The SW300-S has something the DFA can't completely match: the benefits of a much newer generation of technology.

That makes this an interesting comparison.

Rather than simply working our way through two technical data sheets, we're going to look at the question from the perspective that really matters:

What are these operators actually like to install, commission, service and live with?

And ultimately, if we had a door in front of us, which one would we choose?

 

First, the numbers

Before getting into what the two operators are actually like, here's the basic comparison.

Specification	record DFA 127	ASSA ABLOY SW300-S
Operator type	Electromechanical swing operator	Electromechanical swing operator
Length	600 mm	840 mm
Height	85 / 108 mm	70 mm
Depth	124 / 126 mm	Approx. 151 mm
Supply	230 V AC, 50/60 Hz	100–240 V AC, 50/60 Hz
Rated / max. consumption	67 W rated	Up to 350 W
Standby / ECO	13 W standby	Max. 0.3 W with ECO module
Protection	IP20	IP20
Opening angle	70°–115°	Configuration dependent
Maximum door inertia	Approx. 65 kgm²	PUSH 140 kgm² / PULL 80 kgm²
Fire-door applications	Yes, appropriate configuration	Yes, appropriate configuration
Low-energy operation	Yes	Yes
PUSH / PULL	Yes	Yes
Smartphone commissioning	No	Yes
Accessory supply	Configuration dependent	Up to 2,000 mA
Double-door applications	Yes	Yes

There are some pretty obvious differences there.

But as anyone who works on automatic doors knows, the biggest number on a specification sheet doesn't necessarily give you the best door.

 

The DFA 127: the old favourite

Calling the DFA 127 "old technology" is probably doing it a disservice.

Yes, it comes from an earlier generation than the SW300-S, but this isn't simply a motor connected to an arm and a spring.

The DFA uses an electromechanical drive with an integrated spring. As the motor opens the door, energy is stored in that spring and subsequently used during closing, with motor assistance available depending on the configuration.

Behind that is a microprocessor-controlled system monitoring the movement of the door throughout its travel.

It was sophisticated technology when introduced, and the important thing is that the basic concept has proved itself.

There are DFA 127s that have spent years opening and closing doors day after day.

record states that the operator has been tested to one million cycles, but the bigger argument in its favour is probably the number of operators that have effectively been undergoing their own long-term test in real buildings.

Hospitals, shops, offices, schools, commercial properties – they're everywhere.

Engineers know them.

Service companies know them.

Their quirks are understood.

And that counts for a lot.

The SW300-S: the new generation

The SW300-S feels like a product designed for where the automatic door industry is going rather than where it has been.

It's still an electromechanical swing operator, of course, but there is much more emphasis on diagnostics, software-assisted commissioning, energy efficiency, integration and the ability to cover a very wide range of applications with one platform.

That doesn't automatically make it better.

But it certainly makes it interesting.

One of its biggest strengths becomes obvious when we start looking at the sort of doors it can move.

Is the SW300-S really that much more powerful?

On paper, yes – and by quite a margin.

The DFA 127 has a published maximum door-leaf inertia of around 65 kgm².

The SW300-S goes up to:

140 kgm² on PUSH

and

80 kgm² on PULL.

That PUSH figure is more than double the DFA's published maximum.

ASSA ABLOY also describes applications involving doors weighing up to around 450 kg on a 0.8 m PUSH application, subject to the correct configuration and door geometry.

That's a serious door.

But there's an important bit of context here.

Most automatic pedestrian doors don't need anything approaching that capability.

Put either operator onto a fairly normal aluminium commercial entrance and you're unlikely to be standing there wishing you had another 75 kgm² of capacity.

Where the difference becomes useful is when you get one of those doors.

A particularly wide leaf.

A heavy timber or steel door.

A difficult external entrance.

Or simply a door where you look at it during the survey and immediately know the operator is going to have to work for a living.

That's where the additional headroom of the SW300-S starts to become genuinely valuable.

And it's also why comparing operators purely by kilograms isn't particularly helpful.

A 100 kg door that's 800 mm wide isn't the same proposition as a 100 kg door that's 1,400 mm wide. The further that mass moves away from the hinge, the harder the operator has to work.

For an ordinary door, both operators may have more than enough capability.

For the difficult stuff, the SW300-S has the clear advantage.

But the DFA is considerably shorter

This is a good example of why specifications need context.

The SW300-S is only 70 mm high, which is impressively slim for an operator with that level of capability.

The DFA 127 is 85 or 108 mm high, depending on the arrangement.

So visually, the SW300-S wins.

But turn the tape measure the other way and the situation reverses.

The DFA is approximately 600 mm long.

The SW300-S is approximately 840 mm.

That's a 240 mm difference.

If you've got plenty of transom space, who cares?

If you're trying to automate a narrow door with limited space above it, suddenly that 240 mm matters enormously.

So we'd describe the difference very simply:

The DFA 127 is shorter.

The SW300-S is slimmer.

Neither is universally better.

It depends on what's above the door when you arrive.

What about PUSH and PULL installations?

Both operators can handle PUSH and PULL applications.

Again, though, the SW300-S gives the engineer a little more room to play with.

The DFA 127's published maximum recess figures are approximately:

PUSH: 330 mm

PULL: 200 mm

The SW300-S offers approximately:

PUSH: 0–367 mm

PULL: -20–230 mm

The difference isn't enormous, but anyone who installs swing operators regularly will understand why it matters.

Thirty millimetres sounds like nothing in an office.

It can feel like a mile when you're standing on a pair of steps trying to make an arm work on an awkward frame.

Of course, none of these numbers replace a proper survey.

Hinge position, frame construction, opening angle, arm geometry and available fixing points still need to be considered.

But on difficult installations, the SW300-S gives you slightly more flexibility.

What are they actually like as door operators?

This is where the DFA deserves some credit.

It's very easy to get distracted by power figures, apps and electronics and forget that the customer ultimately experiences one thing:

the door moving.

A good automatic swing door shouldn't throw itself open.

It shouldn't slam shut.

It shouldn't hesitate, judder or feel aggressive.

It should accelerate smoothly, control the leaf through its travel, slow appropriately and close consistently.

A correctly set-up DFA 127 does this very well.

Its published adjustments include an opening angle of 70°–115°, hold-open time of 0–60 seconds, opening speed of 3–20 seconds and closing speed of 5–20 seconds.

More importantly, it has a reputation amongst engineers for smooth operation.

And it's quiet.

That's easy to dismiss until you put an operator outside a hospital ward, care-home bedroom, library, office or residential entrance.

On the front of a supermarket, a little mechanical noise may disappear into the background.

At 2am outside somebody's bedroom, it won't.

The DFA 127's smooth and quiet operation remains one of its genuine strengths.

Commissioning is where the generation gap really shows

If you want to see the difference between these two generations of operator, look at how an engineer interacts with them.

The DFA 127 comes from the traditional school.

Its control system is self-learning and microprocessor regulated, and engineers familiar with the product can configure and diagnose it using record's controls and equipment such as the BDE-D display.

Once you understand the DFA, it's a relatively logical operator to work on.

Give an experienced DFA engineer a wiring diagram, meter and access to the operator and they can diagnose a large proportion of faults without needing much else.

There's considerable value in that.

The SW300-S takes a more modern approach.

ASSA ABLOY provides a service app with step-by-step visual guidance during commissioning.

Through the newer interface, engineers can access things such as:

• real-time door information
• error information
• operating statistics
• diagnostics
• troubleshooting information

That's potentially a big improvement, particularly when fault finding.

Instead of simply knowing that something isn't working, the engineer can see more information about what the control system itself thinks is happening.

For businesses with multiple engineers, guided commissioning could also help create more consistency.

One engineer's interpretation of "that's set up nicely" should ideally be the same as another engineer's.

Software can help with that.

Do we actually want an app to commission a door?

This will probably divide engineers.

Software diagnostics are brilliant when they work.

But there's also something reassuring about an operator that an experienced engineer can understand with a meter, technical manual and knowledge of how the system works.

An app introduces another layer.

Engineers need the right equipment. They need access to the software. And, most importantly, they need to understand what the information they're looking at actually means.

For someone who's spent 20 years commissioning automatic doors with a screwdriver and multimeter, the old approach may feel more natural.

For an engineer coming into the industry today, app-based commissioning probably feels completely normal.

Our view?

Good diagnostics don't replace good engineers. They give good engineers better information.

From that perspective, the SW300-S has the advantage.

And which one is actually easier to fit?

Whichever one your engineers know best.

That might sound like we're avoiding the question, but familiarity has a massive effect on installation time.

If you've installed 500 DFA 127s, you'll probably fit and commission number 501 without thinking too hard about it.

If your engineers have been properly trained on the SW300-S and use it every week, the opposite may be true.

Physical dimensions may ultimately make the decision anyway.

The DFA gives you that compact 600 mm length.

The SW300-S gives you the 70 mm slim profile and slightly greater arm/reveal flexibility.

Neither wins every installation.

Survey the door first. Pick the operator second.

External doors are where things get interesting

Anyone who's commissioned an automatic swing door on an exposed entrance will know that the door you tested at 9am isn't necessarily the same door you're dealing with at 3pm.

Wind changes.

Air-conditioning starts.

Extraction systems come on.

Another external entrance opens.

Pressure across the building changes.

And suddenly the door you've just spent an hour setting up starts behaving differently.

The SW300-S incorporates functionality designed to compensate for wind and stack pressure.

This is one of those features that sounds like brochure language until you've actually had to deal with the problem.

On exposed entrances, hospitals, tall buildings and large commercial properties, it can be genuinely useful.

The DFA 127 certainly isn't a lightweight operator. It has a published maximum torque of 50 Nm and has been successfully used on external doors for years.

But where building pressure or wind is known to be a problem, the newer SW300-S has an attractive advantage.

Then there's energy consumption

This is probably one of the clearest examples of how technology has changed.

The DFA 127's published standby consumption is approximately:

13 W

The SW300-S publishes around 5 W at idle, with the optional ECO arrangement capable of reducing power-save consumption to:

less than 0.3 W.

Does that matter on one door?

Probably not enough to choose an operator purely on that basis.

But now imagine an estate with 100, 200 or 500 automatic doors, all energised 24 hours a day.

Hospitals.

Universities.

Airports.

Councils.

Shopping centres.

Large FM contracts.

Suddenly standby consumption becomes a much more interesting conversation.

For large estates and long-term replacement programmes, the SW300-S has a significant advantage here.

Modern doors also have a lot more hanging off them

Once upon a time, an automatic door installation might have been relatively straightforward.

Today you can quickly find yourself powering and controlling activation sensors, monitored safety sensors, touchless switches, access control, electric locks, key switches, indicators, emergency interfaces and other equipment.

The SW300-S provides a 24 V DC accessory supply of up to 2,000 mA.

That's generous.

On a basic door with a couple of sensors, it may not matter.

On a complicated access-controlled entrance with multiple peripherals, it absolutely can.

Having enough power available from the operator can simplify the installation and potentially remove the need for additional power supplies.

It's not the headline feature that sells an operator.

But engineers will appreciate it.

Access control is about more than opening the door

This is another area that's easy to overlook.

A commercial automatic door connected to access control may need to perform something like this:

Access request → unlock → confirm release → open → hold → close → relock

Easy.

Until the electric lock sticks.

Or the door drops slightly.

Or the lock hasn't quite released before the operator starts pulling against it.

Suddenly the sophistication of the control system and the quality of the diagnostic information matter considerably more.

For an access-controlled entrance, the way the operator handles locks, inputs and diagnostics can be every bit as important as how powerful its motor is.

What about safety sensors?

Both operators can work with the monitored door-leaf safety equipment expected on automatic swing doors.

The DFA 127 is commonly used with record RC Swing sensors, including arrangements with two door-leaf sensors on a single operator and four on double-door installations.

The SW300-S similarly supports modern safety equipment.

From the customer's perspective, there may be virtually no visible difference.

From an engineer's perspective, there can be a considerable difference in how easily those sensors are powered, monitored, configured and diagnosed.

Again, the SW300-S's 2,000 mA auxiliary capacity becomes useful when installations start getting complicated.

Fire doors need a different conversation

Both operators have credible fire-door applications.

The DFA 127 has published fire-assessment information and can be used in appropriate fire-door configurations.

The SW300-S is also designed for serious fire-door applications, with published approval for configurations including E30 through EI120 PUSH/PULL applications.

But this needs a warning.

A swing operator being approved for fire-door applications doesn't mean you can fit it to any fire door and automatically have a compliant installation.

The operator is only one component.

The complete doorset matters.

That means considering the door leaf, frame, hinges, ironmongery, operator, arm, sensors, locking, interfaces, power arrangements, closing sequence, installation method and, critically, the relevant test evidence.

Never specify an automatic operator for a fire door simply because the brochure says "suitable for fire doors".

Check that the evidence actually covers what you're proposing to install.

Low Energy doesn't automatically mean compliant either

Both platforms can cover low-energy applications.

The DFA 127 has Full Power, Low Energy and appropriate fire-door configurations. The SW300-S similarly covers everything from fairly straightforward automatic entrances through to much heavier and more specialist applications.

But there's another specification trap here.

Selecting a "Low Energy" setting doesn't automatically make the complete installation suitable.

Door width, weight, speed, opening force, environment, risk assessment and the relevant standards still matter.

And it raises a useful question:

Does a straightforward disabled-access door really need the most powerful operator you can buy?

Usually, no.

Correct specification beats maximum specification.

Double doors

Both operators can run double swing doors.

The DFA 127 has been used extensively in this configuration and has plenty of real-world history behind it.

The SW300-S also supports double doors, but the newer platform brings some interesting integrated options.

For appropriate double fire-door configurations, a mechanical coordinator can be incorporated underneath the operator cover.

The system can also be interlocked with up to six operators.

But double doors are another area where ticking "double door compatible" on a specification sheet doesn't tell the whole story.

You've got sequencing.

Overlapping leaves.

Rebated doors.

Locks.

Mechanical coordination.

Sensor coverage.

Simultaneous operation.

And potentially fire-door closing requirements.

The real question isn't whether an operator can run a pair of doors.

It's how easily the complete pair can be installed, commissioned and maintained.

Don't forget what the door feels like manually

This gets overlooked surprisingly often.

Not everybody waits for an automatic door to open.

People push them.

And a technically excellent automatic installation can still be unpleasant if the door feels unnecessarily heavy or unnatural when opened manually.

Door weight, spring settings, seals, hinges, arm geometry and operator configuration all influence this.

It's another reason why specifying an operator purely from headline motor figures is a mistake.

The finished door needs to work for people, not just satisfy a data sheet.

The DFA 127's biggest advantage isn't on the specification sheet

It's history.

record states that the DFA 127 has been tested to one million cycles.

That's impressive, but there's something arguably more valuable than a laboratory cycle test.

Thousands of operators have been tested every day in actual buildings.

Engineers have installed them.

Maintained them.

Repaired them.

Summary Conclusion

So, which would we choose: the record DFA 127 or the ASSA ABLOY SW300-S?

There isn't a simple winner.

The DFA 127 has earned its reputation. It is proven, reliable, smooth in operation and familiar to a huge number of automatic-door engineers. Its compact 600 mm length is useful on restricted entrances, and years of real-world installations mean its strengths, weaknesses and servicing requirements are well understood.

If we came across an existing DFA 127 that was working correctly and remained suitable for the door, we wouldn't replace it simply because something newer is available. A good DFA 127 is still a good automatic door operator.

The SW300-S, however, shows how swing-door technology has moved forward. Its much greater heavy-door capability, slim 70 mm profile, extremely low ECO consumption, 2,000 mA accessory capacity, app-based commissioning, improved diagnostics and features for wind, pressure, fire-door and more complex installations give engineers considerably more flexibility.

For a straightforward automatic door, some of that additional capability may never be needed. For a heavy, exposed or technically demanding entrance, it could make a significant difference.

That's really what this comparison comes down to.

The DFA 127's biggest strength is its proven history. The SW300-S's biggest strength is its capability and newer technology.

For an existing installation, we'd be perfectly comfortable continuing to maintain a good DFA 127. If that operator required a substantial repair, we'd start comparing the cost of keeping it going against upgrading to a newer platform.

For a completely new installation, particularly one involving a heavy door, demanding external conditions, multiple accessories or more complicated control requirements, the SW300-S would be our preferred choice of the two.

But we'd never choose an operator simply because it has the biggest numbers on the specification sheet.

The best automatic door operator is the one that's correctly matched to the door, environment, safety requirements, expected usage and long-term maintenance needs.

Ultimately, a well-surveyed, correctly installed and properly commissioned automatic door will always matter more than the name written on the operator cover.