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Dorma RTS85 90° Hold Open Transom Door Closer
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Dorma RTS85 90° Hold Open Transom Door Closer
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Delivery Information
| Delivery Time Frame | Delivery Information |
| Next Working Day By 1PM | When an order is placed by 3pm for next working day on certain items |
| Standard Delivery | Usually delivered in 2 to 4 working days |
| Delivery Charges | |
| UK Mainland | Prices start at £3.95 for very small items, £6.50 for small, £9.50 for medium and £20 for large/long items |
| Scottish Highlands & Islands, Northern Ireland & Ireland | Prices from £30, please see our delivery page for more info. |
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£195.79
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£163.16
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Description
Dorma RTS85 90° Hold Open Transom Door Closer
When you need reliable, heavy-duty door control without compromising on clean architectural lines, the Dorma RTS85 90° Hold Open Transom Door Closer provides an ideal engineered answer. Designed to be completely hidden inside the transom header above the doorway, this concealed overhead unit manages busy traffic flows effortlessly while leaving the entrance area clear, modern, and visually welcoming.
Traditional surface-mounted door closers are practical workhorses, but their visible metal bodies and articulated scissor arms can break up the sleek visual continuity of modern commercial entrances. Floor springs offer another discreet option, yet cutting into existing screed, breaking through underfloor heating pipes, or compromising structural floor slabs can introduce massive disruption and spiralling labour costs. The Dorma RTS85 90° Hold Open Transom Door Closer sits cleanly overhead within the transom frame itself, eliminating the need to disturb your floor while keeping external ironmongery entirely out of view.
Supplied as a mechanism-only unit, this closer is engineered to power standard EN4 closing force. It includes an integrated mechanical hold open feature set at 90 degrees, which proves invaluable for retail shops, commercial showrooms, corporate reception areas, and educational buildings where entrances need to stay conveniently open during busy delivery times or continuous customer movement.
Power Size
Fixed EN 4
Door Capacity
Up to 110kg
Leaf Width
Up to 1100mm
Hold Open
Fixed at 90°
Unobtrusive Architectural Concealment
Architectural aesthetics often dictate clean, uncluttered sightlines. Contemporary architectural schemes rely heavily on full-height glazing, slim aluminium profiles, and open spaces. With this concealed transom unit, the closing mechanism remains fully concealed within the frame header section. The only visible elements are the clean perimeter lines of the door itself, allowing glass and metal designs to take centre stage.
Because the closer fits into the horizontal transom rail above the door, there are zero trip hazards, no bulky floor boxes to collect dirt or water, and no external closer arms susceptible to tampering or accidental impact. This makes the system particularly suitable for bustling retail shopfronts, prestigious office lobbies, and boutique hospitality environments where appearance and hygiene are equally essential.
Versatile Single and Double Action Operation
Every commercial building has unique traffic management requirements. The Dorma RTS85 can be paired with appropriate arm configurations and bottom pivots to control single action doors that open in one direction, or double action doors that swing smoothly both inwards and outwards.
Double action swing doors are fantastic for high-frequency settings such as restaurant serving portals, retail corridors, and hotel walkways where visitors and staff approach from both sides simultaneously. The internal cam action ensures that the door returns accurately to the central closed position every time, maintaining draught exclusion, energy conservation, and building security without requiring manual realignment.
Streamlined Off-Site Fabrication and Installation
A substantial advantage of the Dorma RTS85 90° Hold Open Transom Door Closer lies in how it reduces installation time on active building sites. Because the unit fits into a standard transom channel measuring 323mm long, 90mm wide, and 38mm high, aluminium shopfront fabricators can prepare the necessary cut-outs, fixing brackets, and reinforcement blocks in workshop conditions before arriving on site.
When the pre-machined frame and door leaves reach the project location, the installation team simply mounts the closer mechanism into the header rail and connects the door fittings. The unit accommodates either side-load or end-load door mounting arms, which are sold separately. Side-load fittings let installers hook the door leaf directly into position from the side, which is perfect for installations with tight overhead clearance. End-load fittings slide into the top channel of the door profile before the leaf is secured, offering a neat and secure connection.
This straightforward mounting procedure minimises labour costs, prevents accidental scratches to finished powder-coated frameworks, and avoids the messy structural floor excavations commonly associated with heavy floor springs.
Precise Hydraulic Control and Cushioning
A door closer must deliver consistent motion control to safeguard pedestrians, prevent structural wear, and ensure the door latches positively on every single cycle. The Dorma RTS85 mechanism features twin regulation valves alongside mechanical backcheck functionality to keep movement secure and controlled throughout its operating swing up to 130 degrees.
- Adjustable Closing Speed You can fine-tune the primary sweep speed between 130 degrees and 20 degrees using the primary internal adjustment valve. This lets you decide how quickly the door returns towards the frame, balancing traffic turnover with safe, accessible pedestrian passage.
- Adjustable Latching Action The secondary independent valve controls the final 20 degrees of the swing arc. This latching adjustment allows you to accelerate the door slightly to overcome latch resistance, smoke seals, or positive room pressure, or ease it gently into the frame to minimise noise in calm environments.
- Integral Mechanical Backcheck Sudden wind gusts and forceful opening can violently swing a door outward, potentially warping hinges or damaging adjacent walls and framework. The built-in backcheck creates smooth hydraulic resistance as the door opens wide, absorbing excess momentum and protecting your entrance installation.
- Built-in 90° Hold Open Function When the door leaf is swung open to a right angle, the mechanical hold open device engages securely. It keeps the doorway completely unblocked for moving goods, managing peak entry periods, or airing out premises. A firm pull easily disengages the hold open unit, returning the door to controlled hydraulic closing.
Comprehensive Technical Specifications
To ensure the Dorma RTS85 matches your specific architectural project, review the dimensional details and functional capacities summarized below.
| Product Code and Model | Dorma RTS 85 (EN4 90° Hold Open) |
|---|---|
| Power Size Rating | Fixed closing force EN 4 |
| Maximum Door Width | 1100 mm |
| Maximum Door Weight | 110 kg |
| Maximum Door Opening Angle | Approximately 130° |
| Hold Open Angle | Mechanical hold open at 90° |
| Closer Body Dimensions | 323mm (L) x 90mm (W) x 38mm (H) |
| Action Compatibility | Single action or double action doors |
| Applicable Arm Fittings | Side load or end load arms (available separately) |
| Quality and Testing Standards | Tested to EN 1154 and manufactured under ISO 9001 |
Ideal Applications for Transom Closers
The universal design of the RTS85 series makes it a staple specification item for commercial glazing specialists, architectural metalworkers, and facilities maintenance teams. Typical practical scenarios include
- Retail shopfronts fitted with aluminium framing and heavy toughened glass display entrances
- Commercial office vestibules where visual clutter must be kept to an absolute minimum
- Healthcare and educational buildings requiring bi-directional swing doors across central corridors
- Hospitality venues and restaurants requiring convenient 90 degree hold open functionality during peak service periods
- Refurbishment projects where underfloor heating or structural floor slabs rule out traditional floor springs
Quality Manufacturing and Reliable Standards
Dorma is globally renowned for robust engineering, exceptional manufacturing tolerances, and long-term durability. The RTS85 series conforms to the testing requirements of EN 1154 for controlled door closing devices, ensuring proven mechanical efficiency and smooth cycling performance over years of rigorous commercial operation. Furthermore, manufacture under strict ISO 9001 certified quality management protocols assures you of steady, dependable production consistency across every single unit.
Because this listing is for the mechanism only, remember to confirm which specific accessories your doorway requires. Doorfit carries the full range of companion products, including side-load and end-load arm sets, bottom pivot assemblies, weldable pivot boxes, and specialist brackets for diverse frame configurations.
Need Expert Guidance with Your Entrance Hardware?
Our knowledgeable team is ready to help you select the exact arms, pivots, and accessories for your installation.
Specification
| Manufacturer | Dorma |
|---|---|
| Guarantee | 2 Year |
| Type | Transom |
| Power sizes | 4 |
| Finish | N/A |
| CE Certified | No |
| Certifire Approved | No |
| Application | Universal |
| Arm Assembly | N/A |
| Closing Speed | Variable |
| Latching Action | Yes |
| Stand Open | Yes |
| Back Check | Yes |
| Delayed Action | No |
