Product Data Sheet

Magnetic Door Releases
Magnetic Door Releases enable fire doors to be kept open under normal conditions and close independently should an alarm occur. Avaliable in 24 volt DC and 240 volt AC versions, the units are robustly made with die-cast aluminum back boxes that have generous internal wiring space. The units have a high retention value of 45kg for the 24 volt versions and 40kg for the 240 volt versions. The automatic release mechanism is spring loaded and there is a push-button on the side of the box to allow manual release.

Key Features · Small and discreet · Powerful magnet holds securely · Floor mount bracket avaliable · 24 or 240 volt versions · Low power, cool running coils · Spring loaded release prevents sticking · Manual release button

How They Work
Under normal circumstances the electro-magnet within the unit is energised from a local power source enabling it to hold the door open. When the fire control panel enters an alarm condition, a relay is activated switching off power to the MDRs, de-energising the electromagnet and allowing the fire door to close. Note - the door must have a self-closing mechanism fitted. A spring action plunger at the center of the magnet in the unit prevents residual magnetism from delaying or preventing the door from closing.

Application
Magnetic Door Releases are useful in busy corridors and entrances to stairways where self closing fire doors are required but would be inconvenient during normal conditions. The automated closing of the doors completes compartmentalisation of the building and delays spread of fire and smoke.

Installation
Each unit consists of a door plate and solenoid box. The door plate is affixed by means of screws to a solid part of the door. The solenoid base is then fitted to an appropriate place on the adjoining wall. A template is provided to aid drilling. Seperate floor mounting brackets are avaliable for locations where the door does not open against a flat wall.
The 240 volt magnetic door release is powered from a local mains supply and activated via a relay from the fire alarm panel. Note that mains voltages should not be switched within fire panels so an external boxed relay such as our Multikit B should be used.
The 24 volt magnetic door release is ideally powered from a seperate transformer unit such as our TR2 (24 volt 2 amp unit which supports up to 20 MDRs). The TR2 has an internal relay which may be controlled by an external 24 volt signal from the fire panel.

Magnetic Door Releases should ideally be controlled from the fire panel`s non-silenceable fire relay. If an alarm line or other silenceable contact controls the supply to the MDRs, the supply will be restored on silencing the fire alarm, re-energising them. This is contrary to the reccomendations of British Standard BS5839.

Specifications

Version	MDR24	MDR240
Voltage	24v DC	240v AC 50z
Supply Current	83mA	8.3mA
Dimensions	90 x 90 x 52mm deep	90 x 90 x 52mm deep
Holding Force	45kg	40kg
Connections	Screw terminals, up to 2x2.5mm˛ wiring	Screw terminals, up to 2x2.5mm˛ wiring
Mountings	Wall (or floor with FBRA)	Wall (or floor with FBRA)
Magnet diameter	48mm	48mm
Weight	0.8kg	0.8kg

Order Codes

MDR24	24 volt Magnetic Door Release unit complete with door plate
MDR240	240 volt Magnetic Door Release unit complete with door plate
MDFBRA	MDR Floor Mounting Bracket
TR2	24 volt power unit, can power 12x MDR24s constantly
MULTIKIT-B	Boxed dual fire relay for MDR240s

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