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Small malleable iron union fitting with female NPT threads, class 150

Value Brand

Value Brand Union 1/8" FNPT Malleable Iron Class 150 5P588

SKU CH-KB57-44YN1

A malleable-iron Class 150 union with 1/8″ FNPT threads for connecting pipe sections

  • Malleable iron construction handles Class 150 pressure
  • 1/8 inch FNPT threads fit standard piping
  • ZORO SELECT brand ensures reliable quality
  • Compact union design allows easy disassembly
  • New condition guarantees full service life

Zoro Select Union 5P588

This malleable iron union connects two 1/8 inch female NPT pipes in a Class 150 pressure rating. It suits plumbing repairs and low-pressure fluid lines where a removable joint is required. The fitting is supplied new and ready for thread sealant application.

Replaces worn or cracked 1/8 inch unions

Swap this fitting when an existing union leaks at the seat or the nut rounds off during service. The upgrade is worth it when the system pressure stays within Class 150 limits and the media is compatible with malleable iron. Do not use where higher pressure classes or stainless steel are specified.

Simple thread-on installation

Apply PTFE tape or pipe dope to the male threads before tightening the union nut to the recommended torque. The most common error is cross-threading the nut or over-tightening, which cracks the iron casting. Ensure both pipe ends are clean and square for a reliable seal.

How it compares

Measured against everything we stock in Hose Fittings, Adapters & Clamps, at today’s prices. Recalculated every night.

Price $7.99
Cheaper than about 75% of the 2,955 comparable items (median $17.99).

Specifications

Product
Brand nameZORO SELECT

Questions about this item

What thread size does the 1/8" FNPT union require for pipe connection?

The union uses 1/8 inch female NPT threads on both ends, with 27 threads per inch, for direct connection to matching male NPT pipe.

How do you assemble the three-piece union without damaging the seating surface?

Thread each tailpiece onto the pipe first, then bring the centre nut up and tighten it to pull the ground-joint faces together without cross-threading.

When should the malleable iron union be inspected or replaced in a Class 150 system?

Check for leakage, corrosion or cracked threads during routine system maintenance; replace the union if the ground joint no longer seals or threads show deformation.

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