Pentair Transformer 115/230V | MasterTemp / Max-E-Therm / ETi Heaters | 42001-0107Z

Description

The Pentair Transformer 115/230V (42001-0107Z) is the OEM replacement control transformer for Pentair MasterTemp, Max-E-Therm, and ETi series pool and spa heaters.

⚠️ IMPORTANT: LICENSED PROFESSIONAL INSTALLATION REQUIRED
Gas and electrical heater components must be serviced by a licensed pool professional or qualified HVAC technician. Do not attempt to service gas or high-voltage components without proper certification.

This transformer steps down line voltage (115V or 230V) to the low-voltage control circuit that powers the heater’s ignition and safety control board. When the transformer fails, the heater’s control system loses power entirely — the unit will not ignite or respond to thermostat commands. Replacing this transformer restores control circuit operation without requiring replacement of the full control assembly.

Specifications

Fits Into

Compatibility is based on Pentair parts documentation and available OEM records. This is not an exhaustive list. For certainty, verify the part number in your equipment’s manual or on the original part itself before ordering.

Pro Tip

Before ordering, confirm the voltage configuration of your heater installation — 115V or 230V — matches the transformer’s dual-rated input. The part number stamped on the original transformer is the most reliable confirmation. If your heater is completely unresponsive at the control panel with no display activity, the transformer is a logical first diagnostic point for a licensed technician to check before replacing the full control board.