How can a 56 frame wet end be two different sizes?

How can a 56 frame wet end be two different sizes?

Currently we stock a wide variety of wet ends to fit to existing pump motors out in the field. There are many different frame size references such as 48, 56, 71, 90 and so on. In actual fact a 71 frame is a size used on some Balboa Pumps which is actually smaller than the 56 frame used by Waterway and Aqua-flo.

In most cases, pumps will be either 48 frame or 56 frame. These two seem to be the industry standard.

Just to confuse you, however, there are actually two different size 56 frame wet ends supplied by Aqua-flo. There is a 56 frame 6.1” and also a 56 frame 6.3” - Depending on the age of the spa and the pump will determine which size you will need.

Aqua-flo emboss a reference number in the fixing arm to make things a bit easier. To be certain, you can check the distance between the fixing bolts that attach the wet end to the pump.  This is a quick and easy way to tell the difference.

48 Frame Pump:

Distance between bolts: 3⅝" - 9.2cm

56 Frame 6.1" Pump:

Distance between bolts: 4" - 10.2cm

56 Frame 6.3" Pump:

Distance between bolts: 4⅛" - 10.5cm 

Bill Norris, 14-04-2014