1/4" x 3/8" Mini Split Line Set

1/4" x 3/8" Mini Split Line Set for HVAC Installation

The 1/4" x 3/8" Mini Split Line Set is designed for ductless mini split air conditioners, heat pumps, VRF systems and other HVACR installations that require reliable refrigerant copper tubing.

Dabund Pipe has produced HVAC parts, insulated copper pipe and mini split line sets since 2008. This AC copper line set uses 99.9% pure copper tubing that meets ASTM B280 and C12200 standards, combined with black insulation designed for durability, UV resistance, condensation control and installation efficiency.

The 1/4" liquid line and 3/8" suction line combination is commonly used for 0.75 ton to 1.0 ton mini split systems, including 9,000 BTU and 12,000 BTU air conditioning applications. For installers, distributors and HVAC wholesalers, this line set provides a practical solution for residential and light commercial split AC installation.

What is a 1/4" x 3/8" Mini Split Line Set?

A 1/4" x 3/8" mini split line set is a pre-insulated copper tube kit used to connect the indoor and outdoor units of a ductless air conditioning system. It includes two copper tubes: a 1/4" liquid line and a 3/8" suction line.

The two tubes are packed together for easier handling, transportation and installation. Compared with separated copper tubes, a pre-insulated line set helps reduce installation time, protect the copper pipe and improve the overall appearance of the HVAC system.

Key Features of 1/4" x 3/8" Mini Split Line Set

• 1/4" x 3/8" outer diameter, equivalent to 6.35 mm x 9.52 mm.

• 99.9% pure copper pipe meeting ASTM B280 and C12200 DHP copper standards.

• Suitable for ductless mini split, heat pump, centralized air ducted units and HVACR applications.

• Black insulation designed for UV resistance, moisture control and thermal protection.

• Working temperature range from -40℃ to 120℃.

• Insulation can meet ASTM E84, UL94, ASTM D1056 and ASTM G21 requirements.

• Pressure rating range from 2100 PSI to 7000 PSI, higher than common refrigerant system requirements.

• Custom printing is available for company name, size, length, meter marks and branding.

• Available copper tube sizes include 1/4", 3/8", 1/2", 5/8", 3/4", 7/8" and 1-1/8".

• Available line set lengths include 15 m, 20 m, 25 m, 30 m and 50 m.

Copper Tube and Insulation Performance

The copper tube is manufactured from ASTM B280 and C12200 DHP copper, making it suitable for refrigeration and air conditioning systems. The material provides good bending performance, corrosion resistance and stable refrigerant flow for mini split installation.

The insulation uses high-density closed-cell polyethylene foam or black rubber insulation, depending on order requirements. This structure helps reduce heat transfer, control condensation and protect the copper pipe in indoor and outdoor installation environments.

• Insulation: high-density closed-cell polyethylene foam or black rubber insulation.

• Temperature performance: suitable for -40℃ to 120℃ working conditions.

• Fire performance: available with UL94 and ASTM E84 25/50 smoke and flame performance.

• Surface burning characteristics: UL 723 flame spread index less than 25 and smoke development index less than 50.

• Additional properties: superior tear resistance, UV resistance and condensation resistance.

99.9% Pure Copper

Black Rubber Insulated Pipe

Plastic Cap Protection

Features of Pipe Insulation Tubing

The insulation tubing is designed to protect the copper pipe from heat gain, condensation and external wear during HVAC installation. Its closed-cell structure helps limit water vapor penetration and keeps the refrigerant line more stable during operation.

• Black insulation material suitable for -40℃ to 120℃ temperature conditions.

• Moisture-resistant structure helps reduce condensation on the copper pipe surface.

• No extra vapor permeation protective layer is required in many standard applications.

• Good tear resistance helps protect the line set during transportation and installation.

• Clean appearance for exposed mini split air conditioner installation.

Advantages of Dabund Mini Split Copper Line Set

Excellent Heat Preservation

The high-density closed-cell insulation structure helps reduce heat transfer and maintain stable refrigerant performance. It is suitable for HVAC installations where thermal protection and system efficiency are important.

Moisture and Condensation Control

The insulation layer also acts as a moisture-resistant barrier. This helps reduce surface condensation and supports cleaner installation in residential and commercial air conditioning projects.

Flame Retardant Insulation Options

Dabund offers insulation options that meet common flame-retardant and smoke performance requirements, including UL94 and ASTM E84 standards. This makes the line set suitable for different construction and HVAC project requirements.

OEM and Custom Printing Available

The insulation can be printed with brand name, pipe size, length, meter marks and other information. This is useful for HVAC wholesalers, distributors, private-label brands and installation kit suppliers.

1/4" x 3/8" Mini Split Line Set for HVACR Wholesalers and Suppliers

Dabund Pipe manufactures pre-insulated copper line sets for HVAC distributors, contractors, wholesalers and OEM brands. The product is designed to make mini split installation faster, cleaner and more reliable.

With in-house production of insulation and copper line set assembly, Dabund can support stable quality, competitive pricing, custom packaging and bulk shipment for international HVAC customers.

Mini Split Line Set Specifications

Recommended Applications by AC Capacity

Final line set selection should be confirmed according to the air conditioner manufacturer’s installation manual, refrigerant type, installation length and local HVAC code requirements.

Why Choose Dabund Pipe?

Dabund Pipe is a manufacturer of mini split line sets, insulated copper pipe, aluminum pipe and HVAC parts. Since 2008, the company has supplied HVAC products to international customers and supported bulk shipments for distributors and wholesalers.

• Manufacturer of mini split line sets since 2008.

• In-house insulation production for better quality control.

• Support for OEM, ODM, private label and custom packaging.

• Stable export experience and regular 40HQ container shipments.

• Suitable for HVAC distributors, installers, wholesalers and project suppliers.

• Competitive pricing with professional pre-sales and after-sales service.

Dabund Factory

We produce insulated copper pipe, mini split line set, aluminum pipe and HVAC parts.

SGS Certificate

Dabund mini split line set insulation can be made with polypropylene or black rubber insulation with UV resistance, meeting ASTM E84, UL94, ASTM D1056 and ASTM G21 requirements.

Exhibition

Dabund joins HVAC exhibitions worldwide to meet customers, present mini split line set products and support face-to-face cooperation with distributors and installers.

FAQ

What is a 1/4" x 3/8" mini split line set used for?

A 1/4" x 3/8" mini split line set is used to connect the indoor and outdoor units of a ductless mini split air conditioner or heat pump. It is commonly used for 9,000 BTU and 12,000 BTU systems.

Is the copper tube suitable for HVAC refrigerant systems?

Yes. The copper tube is made from 99.9% pure copper and meets ASTM B280 and C12200 DHP copper standards, making it suitable for air conditioning and refrigeration line set applications.

What insulation thickness can Dabund supply?

Dabund can supply black rubber insulation thickness options including 8 mm, 9 mm, 10 mm, 13 mm, 19 mm and 25.4 mm. Custom insulation requirements can also be discussed based on project needs.

Can I customize the line set with my brand?

Yes. Dabund supports OEM and ODM orders. The insulation can be printed with your company name, size, meter marks and other required information.

Can I get a free sample?

Yes. Dabund can send qualified customers free samples. You can request samples through the free sample page. Express cost may need to be covered by the buyer.

Are you a trading company or manufacturer?

Dabund Pipe is a manufacturer of insulated copper pipe, mini split line sets, aluminum pipe and HVAC parts.

What payment terms are available?

Payment terms can include T/T, L/C at sight, credit card and other agreed payment methods depending on order details.

What delivery terms can you offer?

Dabund can offer common international trade terms such as EXW, FOB, CFR and CIF.

How long is the delivery time?

Normal delivery time is usually 15 to 20 days. For urgent orders, production and shipment can be arranged in advance according to factory schedule.