About this item
The LCN 4003T is a heavy-duty track door closer in the LCN 4000T series built specifically for wall pocket mounting on the hinge side of fire and smoke barrier doors. If you're searching "lcn 4003t" or "track closer" and trying to confirm this is the right product for your opening, the key things to know are the mounting style, the door width it's sized for, and why it's paired with a wall magnet on fire-rated applications.
What Wall Pocket Mounting Actually Means
This is where most product descriptions fall short. The 4003T doesn't mount on the door face or on the frame header the way a standard surface-mounted closer does. The closer body recedes into a pocket that's cut into the wall on the hinge side. The track runs along the top of the door and the arm connects the concealed body to the door. From the corridor side, nothing is visible except the track along the door's top edge. The result is a much cleaner architectural appearance on doors where exposed closer hardware would be objectionable -hospital corridors, education facilities, and high-end commercial spaces being the common examples.
The maximum door swing is 90 degrees. That's not a limitation to overlook. The wall pocket installation geometry physically limits how far the door can open. If your door needs to swing past 90 degrees, this isn't the right closer configuration regardless of other factors.
The SEM 7850 Wall Magnet Connection
The 4003T is designed to work with the LCN SEM 7850 electromagnetic wall magnet for hold-open applications on fire and smoke barrier doors. Here's how that system works in practice: the wall magnet holds the door open at a set position during normal building operation. When a fire alarm activates, the magnet de-energizes, the door releases, and the 4003T closer pulls the door shut and holds it closed. That controlled self-closing action is what makes the 4000T series appropriate for fire door applications -the closer itself is UL and cUL listed specifically for fire door duty.
The SEM 7850 is ordered and installed separately. The depth of the pocket at the SEM location is determined by the specific SEM model used, which is why LCN's installation instructions call that out explicitly. If you're retrofitting this closer into an existing wall pocket installation, confirm the pocket dimensions against the 4003T body size (12-1/4" x 3-1/2" x 2-5/32") before you order.
Size 3 -What Door Width It Covers
The 4000T series comes in Size 3 (the 4003T) and Size 4 (the 4004T). Size 3 is rated for interior fire and smoke barrier doors up to 40 inches wide. Size 4 covers wider doors up to 44 inches. The closer size is fixed power -it's not adjustable the way the spring tension is on LCN's 4040XP or 4110 series. That means proper size selection at the time of order matters. If you're in between sizes, go up.
What Ships With the 4003T
The unit ships complete with a standard arm, standard track, track roller, plastic cover, and a wood and machine screw pack. Reinforcement per ANSI/SDI-100 is recommended for hollow metal doors and frames, which is worth flagging to the installer before they start cutting.
Specifications
Model: LCN 4003T
Series: LCN 4000T Wall Pocket Series
Mounting: Wall pocket, hinge pull side
Arm Type: Standard track arm
Maximum Door Swing: 90 degrees
Size: 3 (interior doors to 40" wide)
Closer Body Dimensions: 12-1/4" x 3-1/2" x 2-5/32"
Power: Fixed size (non-adjustable)
Wall Magnet Compatibility: SEM 7850 (sold separately)
Fire Rating: UL and cUL listed, fire and smoke barrier door rated
Cover: Standard plastic cover included
Includes: Standard arm, standard track, track roller, plastic cover, wood and machine screw pack
American Locksets has stocked LCN door closers and the full 4000T series since 2001.
Trusted Since 2001
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