Waterway - 94 mm Pump Union for 2-Inch Pipe (2.5-Inch MBT) - 400-5990

Waterway – 94 mm Pump Union for 2-Inch Pipe (2.5-Inch MBT)

The Waterway 400-5990 is a 2.5-inch hot tub pump union with a 94 mm nut that connects to 2-inch pipe. It is a replacement union for pumps with a 94 mm outside diameter thread (2.5-inch MBT), as used on Waterway (mostly Executive), LX Whirlpool, Aqua-Flo ITT/HydroAir and Balboa pumps.

Compatibility of the Waterway 400-5990 pump union

This spa pump union is suitable for use with several pump brands. The source lists the following:

• Waterway (mostly Executive)
• LX Whirlpool
• Aqua-Flo ITT/HydroAir
• Balboa

The deciding factor is the thread on your pump. The union nut fits pumps whose male thread has an outside diameter of 94 mm, known as 2.5-inch MBT. Measure your pump thread before you order.

Dimensions and fitting

The union has two ends with different sizes, so check both against your plumbing:

• Union thread: 90 mm inside diameter, or 2.5-inch FBT
• Smooth side: 60 mm inside diameter, for 2-inch pipe
• Matching male thread on the pump: 94 mm outside diameter

The smooth side connects to 2-inch pipe. If you are renewing a section of plumbing, 2-inch rigid ABS pipe is available separately.

Replacing a broken union nut

If the nut on your existing union has broken, you can replace it with a two-part nut that is screwed together. This makes it a practical repair when you want to avoid cutting the pipe. The 94 mm pump split nut is listed as a separate product.

What is included

The o-ring is provided with the union. If you need a spare for a 2.5-inch union later on, see the 68 mm o-ring for 2.5″ pump unions.

Not sure whether this is the right fit for your pump? Check the thread size and the brand of your pump, or contact us with the details of your current part before ordering.