1 1/2" Water Manifolds

1 1/2" Water Manifolds. 1 1/2" plumbing fittings doesn't actual measure 1 1/2" it measures 1 7/8" Inside diameter on a slip fitting and 1 7/8" outside diameter on a street fitting.

To figure out what size manifold you need look at the chart below for size conversions.

This is a chart for the outside of your plumbing pipes so you can figure out what size parts to order. Note: The actual size a part is called is not the actual size of the hole in the part it is really the Inside Diameter of the pipe that would glue into that part which doesn’t make sense, since you cannot see inside the pipe. Therefore I am giving you the measurements of the outside of the pipe so you know what size part to order.  For example a part that is ½” plumbing would glue into would actually measure ¾” inside the hole of the part and on the outside of the pipe that glues into the part.

Pipe Outside Diameter chart:

½” Outside Diameter is ¾”

¾” Outside Diameter is 1”

1” Outside Diameter is 1 ¼”

I have never seen 1 ¼” in Hot Tubs

1 ½” Outside Diameter is 1 ⅞”

2” Outside Diameter is 2 ⅜”

2 ½” Outside Diameter is 2 ⅞”