Pentair Max-E-Therm 333 Air Orifice Kit (77707-0112) gfci A kit like this is

A kit like this is useful because it restores the primary temperature-reading component and the safety-related high-limit sensor in one coordinated service package

Helps protect equipment from improper operating conditions

and installation style before purchase

The Hayward volute is designed for compatible Matrix SP1591

Pentair Max-E-Therm 333 Air Orifice Kit (77707-0112) gfci A kit like this isKeep the repair centered on the right component with this Max E Therm 333 Air Orifice Kit. It is used in the heater combustion system to help meter the air path for the correct burner configuration. Because orifice sizing affects how the heater breathes and fires, this is a precision replacement part rather than a generic fitting. Before installation, verify part number 77707 0112, equipment series, and any size or voltage details shown in the product