Resideo tk300-30 Heating Expansion Tank 4.4 Gallon

Product Description

The RESIDEO tk300-30 is a pre-pressurized diaphragm-type expansion tank designed for closed-loop hot water heating systems. It absorbs thermal expansion generated as system water is heated, protecting pipes, fittings, and equipment from overpressure damage. The tank uses a butyl diaphragm to maintain a permanent separation between the air charge and system water, which prevents waterlogging and extends service life. Rated to a maximum safe working pressure of 100 psi and a maximum operating temperature of 240 degrees F, it suits a wide range of residential and light commercial hydronic applications. The 1/2 inch male NPT connection simplifies integration into existing piping. Licensed plumbers and hydronic heating technicians are the primary installers.

This expansion tank is used in closed hydronic heating systems where water is heated and circulated through radiators, baseboard convectors, or radiant floor loops. As water temperature rises, volume increases, and the tk300-30 accepts that expanded volume without allowing system pressure to spike. With a maximum accepted volume of 2.5 gallons and a total tank volume of 4.4 gallons, it is sized for residential and small commercial boiler systems. The steel construction and butyl diaphragm make it suitable for continuous-duty hydronic service.

Key Features

• Pre-pressurized design maintains minimum system pressure and keeps fluid circulating without manual air charging at startup
• Butyl diaphragm permanently separates air charge from system water, resisting degradation from hot water contact
• Rated to 100 psi maximum safe working pressure for compatibility with standard residential boiler systems
• Rated to 240 degrees F maximum operating temperature
• 4.4 gallon total tank volume with a maximum accepted expansion volume of 2.5 gallons
• 1/2 inch male NPT connection for direct integration into standard hydronic piping
• Steel tank construction for durability in continuous-duty heating applications

Compatibility

Designed as an OEM-style replacement or new-installation expansion tank for closed-loop residential and light commercial hydronic heating systems with 1/2 inch NPT connections operating within the rated pressure and temperature limits.

Installation Notes

Installation should be performed by a licensed plumber or qualified hydronic heating technician in accordance with local plumbing codes and the International Plumbing Code (IPC). Shut down and depressurize the boiler system completely before connecting or disconnecting the tank. Verify the tank air pre-charge pressure matches the system fill pressure before placing the system into service. Do not exceed the 100 psi maximum safe working pressure or the 240 degrees F maximum operating temperature under any operating condition.

Technical Specifications

• Product Type: Expansion Tank
• Tank Volume: 4.4 gallons
• Maximum Accepted Volume: 2.5 gallons
• Diameter: 11 inches
• Height: 15.5 inches
• Material: Steel
• Thread Size: 1/2 inch
• Thread Type: Male NPT
• Maximum Safe Pressure: 100 psi
• Maximum Operating Temperature: 240 degrees F

Standard Information

• Brand: RESIDEO
• Manufacturer Part Number: tk300-30