LCN 3133 Concealed (in door) Door Closer, Size 3

The LCN 3133 is the Size 3 variant in the LCN 3130 Series concealed in-door door closer family, specified for interior commercial doors 34" to 38" wide. The cast iron cylinder and standard arm are completely concealed in the top rail of the door, with the track concealed in the head frame, so nothing is visible when the door is closed. Single acting, handed for either right-hand or left-hand doors (specified at order). UL and cUL are listed without hold-open for self-closing doors, ANSI A156.4 Grade 1 certified for commercial heavy-duty applications. 

What Is the LCN 3133 Concealed Door Closer

LCN (founded 1926, acquired by Allegion in 2013 alongside Schlage and Von Duprin) builds the industry's most specified premium door closer line, with the 3130 Series being the flagship concealed-in-door family. "Concealed" here means the closer body sits inside the hollow metal door itself (not in the frame, not on the surface), which is the aesthetic choice for high-end office lobbies, executive suites, hotel corridors, hospital patient rooms, upscale healthcare facilities, and any interior opening where architects and designers don't want a visible closer on the push side of the door. The 3133 specifically covers Size 3 door widths (34" to 38") in single-acting configuration, making it the most commonly specified size in the family because 36" is the standard width for most commercial interior doors per ADA and IBC code.

LCN 3133 Specifications

Full specs for the door schedule:

• Type: single acting concealed in-door door closer

• Series: LCN 3130 Series

• Size: Size 3 (interior door width 34" to 38", or 864mm to 965mm)

• Cylinder: cast iron, concealed in top rail of door

• Arm: standard arm, concealed in top rail

• Track: concealed in head frame

• Door thickness: 1-3/4" (44mm) minimum

• Door width: 2'2" (660mm) minimum

• Top rail minimum: 4" (102mm) required for cylinder housing

• Handing: handed specific (right-hand or left-hand must be specified at order, the 3133 is not field-reversible)

• Listings: UL and cUL listed without hold-open for self-closing doors

• Standard: ANSI/BHMA A156.4 Grade 1 certified commercial heavy duty

• Finishes: ALUM 689 Aluminum (standard), DKBRZ 695 Dark Bronze, LTBRZ 691 Light Bronze

• Packaging: standard arm, standard track, wood and machine screw pack, mounting template

LCN 3130 Series Size Guide (3131 vs 3132 vs 3133)

The 3130 Series covers three sizes under the same concealed in-door chassis. LCN 3131 is Size 1 at $556.77, designed for narrower doors up to 30" and ADA-compliant for low opening force (5 lbf interior). LCN 3132 is Size 2, covering doors 30" to 34" wide, the middle option for standard office doors. Sizing is purely about the size of the door the closer needs to control, not finish or function - all three sizes ship with the same three finish options and identical installation template format. If you're unsure which size fits your door schedule, the rule is simple: measure the door width, then pick the size whose range covers it. For door widths over 38" (exterior doors, large vestibules, double-door openings), step up to the LCN 2030 Series concealed-in-frame closers instead of the 3130 Series.

Template and Mounting Requirements for the 3133

Before ordering, installers should verify four dimensions against the existing door. First, the door must be minimum 1-3/4" (44mm) thick - almost all commercial hollow metal doors meet this, but residential-grade doors typically don't. Second, the top rail must be minimum 4" (102mm) high to accommodate the cylinder housing - this is where most retrofits fail, because some older commercial doors have narrower top rails that can't hide the 3130 cylinder. Third, the door width must be minimum 2'2" (660mm) and fall within 34" to 38" for the 3133 specifically. Fourth, the head frame must accept the concealed track mounting. The full installation template ships in every 3133 order, and the LCN 3130 Series catalog (linked in the product page resources section) includes complete dimensioned drawings and mounting diagrams. For pre-order template verification, the LCN 3130 catalog PDF from Allegion is available on the official LCN page, so you can confirm fit before purchase.

Configure Your 3133 (Finish and Handing)

Two selections at checkout. Finish: ALUM 689 Aluminum (the default for 95% of commercial specs, most neutral under fluorescent and LED lighting), DKBRZ 695 Dark Bronze (for hospitality, executive offices, and aesthetic applications pairing with oil-rubbed bronze hardware), or LTBRZ 691 Light Bronze (less common, used for specific mid-century and vintage restoration applications). Handing: Right Hand or Left Hand. Handling is determined standing outside the door looking at the push side: if hinges are on the right it's RH, if hinges are on the left it's LH. Unlike many modern closers that ship non-handed and adjust in the field, the 3130 Series is factory-handed at order, so specifying correctly matters. For mixed handing door schedules, order RH and LH units separately and verify each against the door schedule before installation.

Where to Buy the LCN 3133

We've stocked LCN door closers since 2001, and the 3133 ships the same day from the full LCN 3130 Series Concealed Closer lineup within our broader Overhead Concealed Closers and Door Closers categories. For complete concealed door control installations, compatible accessories include the LCN 2030-3054 Hold-Open Clip, LCN 2030-417 Wood Mounting Clip Set, LCN 2030-169 Track Bumper, and LCN 2030-420 Fire Shield for fire-rated openings.