Description
Important: This Hayward Union Adapter Assembly has been discontinued by the manufacturer
This specialized adapter fitting enables conversion from the legacy Hayward 2″ Thin Threaded Union configuration to a standard 1-1/2″ threaded connection, which measures 1 7/8″ O.D. for typical wet end applications.
While an O-Ring is included with this fitting, replacement O-rings are available separately under part number HTP90-423-5226 if needed.
Important: The Hayward thin thread pump union appears similar to standard 2″ threaded unions and has comparable measurements, but features distinctively fine, tight threading. The Hayward version measures approximately 2 15/16″ across the threads internally, slightly smaller than conventional unions which measure roughly 3″ inside the union across threads.
Important: A different adapter exists for converting 2″ Unions down to 1-1/2″ Thread, commonly found on Master Spas circulation pumps and similar equipment. That alternative adapter is part number HTP89-402-1126.
This particular adapter is designed to convert standard union threads to the specialized larger Hayward union thread pattern, enabling installation of pump wet ends with conventional union threading into Hayward-specific setups.
| Union Fitting Type | Adapter |
| Union Fitting Application | Pump 1-1/2″ |
| Plumbing Connection Size “A” | 1-1/2″, 2″ |
| Plumbing Connection Type “A” | Female Buttress Thread (fbt), Male Buttress Thread (mbt) |
| Plumbing Connection Size “B” | 1-1/2″, 2″ |
