Swimables Control Board Kit Compatible with Mastertemp Heaters

In this review of the Swimables Control Board Kit compatible with Mastertemp and Max-E-Therm Pentair pool and spa heaters, the bottom line is simple: this is a practical, direct replacement for owners whose heater display no longer illuminates or whose unit fails to start. Intended for DIY-minded pool owners and service technicians, the kit restores core control functions quickly by swapping the old mastertemp board for a ready-made replacement. It is especially useful when you need a like-for-like fix for Pentair Mastertemp 400 and related NA and LP series systems.

Key Features

• Compatibility: Replaces the Mastertemp 400 control board and fits a range of Pentair models so you can repair several NA and LP series heaters without adapter parts.
• Complete kit: Includes the replacement board and four mounting screws so installation requires no extra fasteners.
• Simple diagnosis: The review highlights how a non-illuminated display or failure to start reliably indicates the board is the likely fault, making troubleshooting straightforward.
• Step-by-step installation: The board is installed by unplugging the membrane pad, removing wire connectors, unscrewing four screws, and reconnecting the new board, which most DIYers can follow.
• Made in USA: The product is manufactured domestically, which can reassure buyers who prefer locally made pool components.

Who It's For

This control board kit is aimed at pool owners and independent service technicians who need a fast replacement part for Pentair Mastertemp 400, Mastertemp 300, Mastertemp 200, Mastertemp 125 Low Nox, and compatible HD units. If the symptom is a blank display or a heater that fails to start, this kit targets the most common electronic failure with a like-for-like swap.

Those who should look elsewhere include buyers seeking a long-term overhaul or managers of commercial pools who need industrial-grade, high-durability controls; several customer reports note rust and durability concerns over months, so high-corrosion environments may require more robust OEM options.

Pros & Cons

Pros

• Direct compatibility with multiple Mastertemp models makes the kit versatile for repairs.
• Includes necessary screws and a ready-to-install board, reducing trip times to parts suppliers.
• Clear installation steps let a competent DIYer replace the board without specialized tools.
• Positive feedback for functionality and plug quality indicates reliable electrical connections on arrival.

Cons

• Some customers report durability issues, including corrosion or rusting within months, so longevity can vary by environment.
• Fit and perceived value receive mixed reviews, so budget-conscious buyers should compare options.

Specifications

Product type	Control board kit for pool and spa heater
Compatible models	Mastertemp 400, SR333NA, Mastertemp 300, SR200NA, Mastertemp 200, Mastertemp 125 Low Nox
Includes	Replacement board (42002-0007s) and 4 screws
Series compatibility	All NA and LP series Pentair heaters, includes HD heaters
Installation	Unplug membrane pad, remove connectors, unscrew 4 screws, install and reconnect
Origin	Made in USA

Our Verdict

The Swimables Control Board Kit is a practical repair part for anyone needing a like-for-like replacement for Pentair Mastertemp series heaters; it restores control functions quickly and includes the mounting hardware. It represents good value for DIY repairs, though buyers in corrosive environments or those needing extended durability should consider heavier-duty OEM options.

Frequently Asked Questions

Will this board work on a Mastertemp 400?
Yes. The kit is designed to replace the Mastertemp 400 control board and is compatible with several related Pentair models.

What tools are needed to install the board?
Basic hand tools to remove four mounting screws and to unplug wire connectors are sufficient; no special tools are required.

How do I know the control board is the problem?
If the heater display is not illuminated or the unit will not start despite power and basic checks, a failed control board is a common cause and worth replacing.