Zurn XT-18 Lead-Free Thermal Expansion Tank, Carbon Steel, NPT

The Zurn Wilkins XT-18 is a potable water-heater thermal expansion tank with a 4.8 gallon total volume, factory pre-charged to 40 psi. It is not suitable for fire sprinkler systems (per NFPA 13/13D). It features a carbon steel body. Rated to 80 psi and up to 200°F. This model is certified lead-free for potable-water installations.

The XT Thermal Expansion Tank is utilized on potable water lines between the backflow preventer or pressure reducing valve and the water heater for protection against water thermal expansion in residential applications. As the system pressure increases, water enters the polypropylene-lined water chamber of the tank, expanding a diaphragm into a pre-charged air chamber to keep the system pressure below the relief valve setting. Materials include a carbon steel shell with an epoxy finished coating, and corrosion-resistant stainless steel connection with a polypropylene liner and Butyl rubber diaphragm.

Features

• Pre-charge is field adjustable for convenient maintenance
• Carbon steel shell with polypropylene liner ensures long-lasting construction
• Diaphragm style tank is ideal for thermal expansion protection in residential applications
• Stainless steel connection resists corrosion
• Low-lead law compliant
• IAPMO® Listed
• Water Quality Association - Certified to NSF/ANSI 61 & 372

Common Questions

Is this rated for potable water?

Yes. It is IAPMO Listed, certified to NSF/ANSI/CAN 61 and NSF/ANSI 372, and sits between the backflow preventer or pressure-reducing valve and the water heater on the potable cold-water supply.

Can I use this on a fire sprinkler system?

No. Zurn’s own sheet states this tank is not suitable for fire sprinkler systems as required by NFPA 13 or 13D.

What size do I need?

This model holds 4.8 gallons total, of which 2.4 gallons is usable acceptance volume (the expanded water the diaphragm can take before the pre-charge is overcome) -- size off the acceptance volume against your water heater’s expansion, not the total shell.

Do I need to adjust the pre-charge?

Match the factory 40 psi pre-charge to your incoming supply pressure before putting the tank in service (adjust with no water pressure in the tank), and confirm a relief valve set at a maximum of 150 psi is installed in the system.

Specifications

• Type: Thermal Expansion Tank
• Connection: NPT
• Body Material: Carbon Steel
• Max Pressure (psi): 80
• MPN: XT-18
• Temperature: up to 200°F
• Certifications: NSF-61, NSF-372
• Lead-Free: Yes
• Component: Expansion Tank
• Tank Volume (gal): 4.8
• Acceptance Volume (gal): 2.4
• Potable Water Rated: Yes
• Pre-Charge Pressure (psi): 40