Thermopan 44008 Rectangular Thermo Thimble Kit

Product Description

The THERMOPAN 44008 is a rectangular thermo thimble kit designed to create a clean, air-tight wall penetration for mini-split and split-system line sets. The kit seals the opening where refrigerant lines, electrical conduit, or drain tubing pass through an exterior wall, preventing air infiltration, insect entry, and moisture intrusion. High-density foam gaskets compress against the wall surface to form a lasting seal on both siding and masonry substrates. The 44008 measures 2.25 inches by 3.125 inches and is suited for new construction installations and retrofit applications alike. HVAC technicians install this fitting as a finishing detail on ductless and traditional split-system line set runs.

This thimble kit is commonly used on residential and light-commercial split-system installations where line sets penetrate exterior walls. The rectangular profile accommodates typical line set bundles and eliminates the need to patch or caulk an oversized hole after the lines are run. It is appropriate for use on wood-frame siding, stucco, and masonry wall assemblies. Installation is straightforward, making it a practical add-on for new builds or when retrofitting an existing structure with a new HVAC system.

Key Features

• Rectangular 2.25 x 3.125 inch opening fits standard mini-split and split-system line set bundles
• High-density foam gaskets form an air-tight seal to block conditioned air loss, insects, and pests
• Installs on siding or masonry walls without special tools
• Eliminates exposed wall gaps and removes the need to patch around line set penetrations
• Suitable for new construction and retrofit applications
• Reduces labor time compared to field-fabricated sealing methods

Compatibility

Designed as an OEM-style line set wall penetration fitting for residential and light-commercial split-system and ductless mini-split installations where a rectangular thimble profile is required.

Installation Notes

Installation is performed by a licensed HVAC technician as part of the line set routing process. Power down the system and ensure the line set is fully routed through the wall before seating and securing the thimble kit. Follow local mechanical codes for exterior wall penetration requirements, including any sealing or fire-blocking provisions that may apply. Do not compress the foam gaskets excessively, as this can reduce their sealing effectiveness against the wall surface.

Technical Specifications

• Opening Size: 2.25 inches x 3.125 inches
• Profile: Rectangular
• Gasket Material: High-density foam
• Wall Substrate Compatibility: Siding and masonry

Standard Information

• Brand: THERMOPAN
• Manufacturer Part Number: 44008