What you should know before you buy an FD20 & FD20-UG

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01.04.2026

The Gilgen FD20 and FD20-UG are powerful swing door operators designed to handle everything from lightweight internal doors to heavyweight external entrances. 

Both are incredibly robust, the difference is that FD20-UG installs discreetly within the floor threshold with rust-resistant aluminium, while the FD20 requires lintel space as it sits above the door frame. This makes FD20-UG better equipped for refurbishments and FD20 suits new builds.  

Here’s everything you should know about both before you invest. 

When FD20 swing doors work best 

The FD20 is an all-rounder, heavy-duty swing door that works reliably as both an internal and external door. It’s built to handle high-traffic environments, adverse weather, and demanding applications without compromise. 

Industries & applications 

Excelling across a diverse range of sectors, including but not limited to:

• Healthcare – Handles high footfall, infection control & hands-free access 
• Retail –  Heavy door can manage high-street usage & external wind exposure
• Education – Reliable, low-maintenance operation 

Thanks to its robust and versatile features, such as:

• Wind-resistance performance – Operates smoothly in winds up to 80km/h
• Heavyweight capacity – Handles doors up to 250kg
• Quiet operation – Smooth, near-silent movement 
• Control modes – Full power (automatic), low energy (push-assist) and inverse (fail-open for emergency ventilation) options 
• Future-proof – USB software updates extend service life and add functionality without hardware replacement 
• Built-in compliance – TÜV-Nord tested and EN 16005/DIN 18650 certified with integrated fire safety (spring-actuated closure, emergency exit capability, optional smoke detection) 

When to use FD20 vs FD20-UG

Choose FD20:

• New builds with available above-door space 
• Aesthetic integration matters – powder-coated RAL finishes to blend with building design 
• Standard installation is preferred 
• Budget is the primary concern – lower upfront costs 

Choose FD20-UG:

• Retrofitting existing doors 
• Floor-level aesthetics matter – underground mounting creates a seamless threshold
• Moisture is a concern – IP64-rated rust-resistant aluminium extends lifespan
• Serviceability without disruption – maintains the unit without door removal 
• Refurbishment projects that require minimal structural changes 

What’s the difference between FD20 & FD10 swing doors?

FD10 is the compact and elegant swing door operator for internal efficiency, which doesn’t require external durability. FD20 is the upgrade when performance demands increase. 

Feature	FD10	FD20
Primary use	Internal doors only	Internal + external doors
Outdoor capability	❌	✔️
Resilience	Standard	Wind load regulation, reinforced closure
Integrated LCD panel	Graphic display screen	LCD control panel
Installation	Lintel or door-leaf mounted	Transom or door-leaf mounted
Quiet operation	✔️	✔️
Emergency exit capability	✔️	✔️
Best suited for	Lightweight internal traffic	High-traffic exposure

Installation & set up 

Both the FD20 and FD20-UG must be plugged into a standard UK electrical socket (240V), with a safety switch installed by a qualified electrician. The main difference is where they sit: the FD20 mounts above the door frame, while the FD20-UG sits hidden in the floor threshold. 

GDUK provides full installation services across the UK. We recommend a site survey to confirm the door’s suitability and installation requirements before purchase. 

Maintenance & support 

The FD20 and FD20-UG are built to last, but like anything that is used frequently and exposed to tough weather, they eventually need maintenance and repair. 

When you buy swing door operators with GDUK, we can set up a maintenance and repair contract tailored to your needs. Our comprehensive support covers all manufacturers and product types, with guaranteed prompt response times and engineers located across the UK. 

Whether you get a contract with us or not, our e-shop has all the automatic door components and kits you need to repair and replace for your swing door operator. 

Is FD20 right for you?

If you’re looking for a door that works seamlessly day after day, in high-traffic areas, FD20 and FD20-UG are dependable for the job. 

Call 0800 316 6994, email estimating@gdukds.com, or fill out the form below to get a quote for your swing door operator, or find the automatic door components you need.