Waterway - Reducer 2" Male to 1.5" Female for Spa Plumbing - 421-4070

Waterway – Reducer 2″ Male to 1.5″ Female for Spa Plumbing

The Waterway reducer 2-inch male to 1.5-inch female (part number 421-4070, also listed as 437-251) is a hot tub plumbing fitting that joins 2-inch and 1.5-inch pipework. It is a ring-type reducer: the 2-inch male side pushes into a 2-inch female fitting, while the 1.5-inch female side takes 1.5-inch pipe directly. Use it as a replacement spa reducer when you need to step down from 2 inch to 1.5 inch without adding an extra length of pipe.

How the 2-inch to 1.5-inch reducer works

This Waterway reducer connects a 2-inch pipe and a 1.5-inch pipe together. The 2-inch male side inserts into a female fitting, such as an elbow or a straight connector. The 1.5-inch female side connects directly to 1.5-inch pipe.

Because it is of the ring type, it fits fully into 2-inch female couplings. This lets you reduce the opening of a coupling without using an additional pipe, which keeps the connection simple when you are working on your hot tub or spa plumbing.

Dimensions of the 421-4070 reducer

The sizes below are the ones to compare with your existing plumbing:

• Outside diameter, large side: 60 mm
• Inside diameter, small side: 48 mm, for 1.5-inch pipe
• Large side: 2-inch male
• Small side: 1.5-inch female

Pipe sizes on spas are often quoted in inches, while parts are measured in millimetres. If you are unsure which size you have, see our guide Confused by sizes in inches and millimetres? before you order.

How to choose the right reducer

Start by checking the direction of the connection. The name tells you what to expect: the 2-inch side is male and the 1.5-inch side is female. The 2-inch side therefore needs a 2-inch female fitting to go into, and the 1.5-inch side is made to receive 1.5-inch pipe.

Measure the pipe and the fitting on your spa, and compare the figures with the dimensions listed above. If your old reducer carries a number, check whether it matches 421-4070 or 437-251.

What this page covers

This page is for the single reducer fitting only. Pipe, elbows, connectors and other plumbing parts are separate items, so make sure you have everything you need for the rest of the connection before you start the job.