Product Overview

The Pentair 351157 SuperFlo / SuperMax 1.5" Union Kit is a genuine OEM replacement plumbing connection kit designed for compatible Pentair SuperFlo® and SuperMax® pool pumps.

This complete union kit provides the components needed to connect both the suction and discharge sides of the pump. The union-style connections make pump installation and future servicing easier by allowing the pump to be disconnected from the plumbing without cutting PVC pipe.

Pentair specifies 351157 as the complete union kit containing two union adapters, two adapter O-rings, and two union nuts, providing enough components for both pump ports.

Key Features

• Genuine Pentair OEM replacement part
• Manufacturer Part Number: 351157
• Designed for compatible Pentair SuperFlo® and SuperMax® pumps
• 1.5-inch plumbing connection
• Black union nuts
• Complete kit for both pump connections
• Services both suction and discharge ports
• Makes pump removal and servicing easier
• Helps create secure, watertight plumbing connections
• Reusable union design allows future pump removal without cutting PVC
• Ideal for new installations and replacement plumbing

What's Included

One Pentair 351157 Union Kit includes:

• 2 × Union Adapters
• 2 × Union Adapter O-Rings
• 2 × Black Union Nuts

This is a complete two-union kit, providing connections for both the inlet and outlet of one compatible pump.

Specifications

Compatibility

Pentair 351157 is designed for compatible:

• Pentair SuperFlo® VST
• Pentair SuperFlo® VS
• Pentair SuperMax® VS
• Select SuperFlo pump configurations
• Select SuperMax pump configurations

Pentair's current replacement-parts documentation specifically identifies 351157 as the SuperFlo/SuperMax Union Kit.

Compatibility Note

Always verify the pump model and existing plumbing size before ordering. Pump generations and plumbing configurations can vary.

Individual Components

Pentair identifies the components contained in the 351157 kit as:

Purchasing 351157 provides the complete set instead of ordering these components individually.

Why Use Pump Unions?

Pool pump unions make equipment installation and maintenance significantly easier.

Without unions, removing a pump may require cutting the existing PVC plumbing. With properly installed union connections, the union nuts can be loosened and the pump removed while much of the existing plumbing remains intact.

This is especially useful when:

• Replacing a pump
• Servicing the pump motor or wet end
• Rebuilding the pump
• Repairing equipment-pad plumbing
• Winterizing equipment
• Temporarily removing equipment

When Should the Union Kit Be Replaced?

Consider replacing the existing unions if you notice:

• Water leaking around the pump connections
• Cracked union nuts
• Damaged plumbing adapters
• Flattened or deteriorated O-rings
• Cross-threaded union nuts
• Previous plumbing modifications
• Missing original union fittings
• Difficulty obtaining a secure seal

Replacing the complete kit can be preferable when several pieces of an older connection are worn or damaged.

Installation Information

Before servicing pool equipment:

1. Turn off power to the pool pump.
2. Relieve pressure from the filtration system.
3. Drain water from the plumbing as necessary.
4. Remove the existing union components.
5. Install the new union adapters into the plumbing.
6. Position the supplied O-rings correctly.
7. Thread the union nuts onto the pump connections.
8. Hand-tighten the unions securely.
9. Restart the system and inspect for leaks.

Avoid overtightening plastic union nuts, as excessive force may damage the fittings.

Frequently Asked Questions

Does Pentair 351157 include two unions?

Yes. The kit contains enough components for two complete pump connections—one for the suction side and one for the discharge side.

Are the O-rings included?

Yes. Two union adapter O-rings are included.

Are the union nuts included?

Yes. The kit contains two black union nuts.

Does it fit the Pentair SuperFlo VST?

Yes. Pentair lists 351157 in its SuperFlo VST replacement-parts documentation.

Does it fit the SuperFlo VS?

Yes. It is listed for compatible SuperFlo VS pump configurations.

Does it fit SuperMax VS?

Yes. Pentair lists the kit for compatible SuperMax VS pumps.

Is this a single union?

No. 351157 is a complete two-union kit.

What size plumbing is this for?

The kit is designed for 1.5-inch plumbing connections.

Is this a genuine Pentair part?

Yes. 351157 is a genuine Pentair OEM replacement union kit.

Can I reuse the unions when replacing my pump?

Generally, union fittings can be disconnected and reused if the components and O-rings remain undamaged and compatible with the replacement pump.