Waterway - 78 mm Pump Union for 2-Inch Pipe - 400-5570

Waterway – 78 mm Pump Union for 2-Inch Pipe

The Waterway 400-5570 is a replacement hot tub pump union with a nut for pumps that have a 78 mm outside diameter thread (known as 2-inch MBT). It connects to 2-inch pipe and suits several pump brands, including Waterway, LX Whirlpool, Aqua-Flo ITT/HydroAir and Balboa. Before ordering, check the thread size on your pump, as this union does not fit every make.

Compatibility of the 400-5570 pump union

This spa pump union is compatible with pumps from several manufacturers, including:

• Waterway
• LX Whirlpool
• Aqua-Flo ITT/HydroAir
• Balboa

It does not fit pumps made by Espa or Davey Spa Power. If you are unsure about your pump, compare the thread on the pump with the measurements below.

Thread size and dimensions

The nut screws onto the male thread on the pump, which must have an outside diameter of 78 mm. The measurements of the union are:

• Inside diameter of the union thread: 75 mm or 2-inch FBT
• Inside diameter of the smooth side: 60 mm, for 2-inch pipe
• Outside diameter of the matching male thread on the pump: 78 mm

Repairing a broken nut

If the nut of an existing union breaks, you can replace it with a 78 mm pump split nut. This is a two-part nut that is screwed together, which makes it a practical choice for repairs when you want to avoid cutting the pipe.

What is included

The union is supplied with its o-ring, so you have the seal you need when fitting it to the pump.