Product Overview

The Pentair 473381 PVC Union is a high-quality 2″ × 2″ union fitting with a built-in O-ring seal, designed for pool and spa plumbing systems — especially for use with heater and heat-pump connections such as ThermalFlo®, UltraTemp®, MiniMax® Plus, and similar Pentair models. Built from durable PVC, this union provides a secure, leak-resistant connection while allowing for easy disassembly and maintenance of plumbing sections.

Ideal For

• Pool and spa heaters or heat-pump systems (like ThermalFlo / UltraTemp / MiniMax Plus) requiring a reliable 2″ PVC union connection. 

• Maintenance and service professionals needing a robust union for plumbing repairs, heater retrofits, or periodic disassembly.

• Installations where a chemical-resistant, corrosion-resistant union is necessary to withstand pool water and heater conditions.

• Pool owners seeking an OEM-grade PVC union that ensures a leak-proof, service-friendly connection in heater plumbing assemblies.

Key Features

• 2″ × 2″ PVC Construction — sized for standard 2″ plumbing commonly used in pool/spa heater and pump plumbing loops. 

• Integrated O-Ring Seal — provides leak-resistant performance under pressure and chemical exposure, reducing risk of leaks or water intrusion. Durable, Chemical-Resistant Material — PVC construction ensures resistance to pool chemicals, salt, and long-term wear under heater or pump conditions. 

• Easy Disassembly & Maintenance — the union design allows quick removal and re-installation for service, cleaning, or plumbing modifications. 

• Compatibility with Multiple Heater/Heat-Pump Models — confirmed for use with Pentair ThermalFlo®, UltraTemp®, MiniMax® Plus, and similar pool-heater systems. 

Customer-Facing Q&A

Q: What does this union do and why is it needed?
A: It provides a secure, leak-resistant 2″ plumbing connection between pool equipment (heaters or heat-pumps) and the pool plumbing system. The integrated O-ring helps maintain a tight seal even under pressure and chemical exposure.

Q: Will this part fit my heater or heat-pump?
A: Yes — it is compatible with many Pentair units including ThermalFlo®, UltraTemp®, MiniMax® Plus, and other pool/spa heater systems that use 2″ PVC plumbing. 
Q: Is installation difficult?
A: No. The union is designed for easy installation and removal. It simplifies plumbing layout, maintenance, and repairs because it can be disconnected without cutting pipe.

Q: Is the O-ring replaceable?
A: Yes — because it’s a union, you can disassemble it to inspect or replace the O-ring if needed, allowing for maintenance without replacing the entire union.

Q: Can I use this in salt pools or with chlorinated water?
A: Yes — the PVC material and union design are built to resist chemical corrosion and are suitable for standard pool water, including salt systems, provided plumbing and water chemistry are maintained properly.