Funmit High-Limit Temperature Switch for Pentair Spa/Pool Heaters — 135°F Direct Replacement (42001-0063S)

The Funmit 42001-0063S is a direct-replacement high-limit temperature switch (135°F) designed to shut off your Pentair-compatible pool or spa heater when water gets too hot.

When a heater runs hotter than intended, a reliable high-limit switch is the safety component that interrupts power to the heat exchanger. This replacement part matches several Pentair and Sta-Rite models and restores the safety cutoff function quickly and affordably, helping you avoid costly service calls or prolonged downtime.

Which heaters will this high-limit switch work with?

This Funmit sensor is built to replace OEM part numbers used across multiple Pentair/Sta‑Rite families, including MasterTemp and Max‑E‑Therm units. Always verify the original part number before purchase to ensure a match.

• Compatible with Pentair, Sta‑Rite, MasterTemp, Max‑E‑Therm heaters
• Replaces part numbers 42001-0063S, 42001-0064S, HMXHLI2932, HAXHLI1930, STA-151-6255
• Designed for systems using a 135°F high-limit threshold
• Fits the same mounting and electrical connector locations as the originals

How does installation typically go?

Installation is straightforward for anyone comfortable with basic heater maintenance and simple electrical disconnects. The switch mounts in the existing sensor opening and plugs into the same connector, so you can often finish the swap in minutes.

• Remove power to the heater before starting
• Unplug the original sensor and slide the new Funmit unit into position
• Reconnect the electrical connector and secure the switch in place
• No special tools or calibration required for most models

What function does this high-limit switch perform?

The device monitors water/heat exchanger temperature and opens its contact when the threshold is reached, cutting power to the heater element or gas control. It’s a safety interlock—preventing overheating and protecting the heater’s components.

• Senses temperature and opens circuit at approximately 135°F
• Stops the heater from continuing to heat once the limit is exceeded
• Helps protect the exchanger and surrounding components from excessive heat
• Functions as a passive, mechanical/electrical safety device

Can replacing this switch save me money?

Yes—installing a compatible Funmit replacement is typically far less expensive than dealer parts or a service visit. It lets you restore proper safety operation quickly and delays or avoids larger repairs when the failure is limited to the high-limit sensor.

• Lower cost than many OEM dealer parts
• Quick DIY swap reduces labor expenses
• Restores heater safety and operation without full system replacement
• Backed by Funmit customer support for quality concerns

Who is this for: Owners and technicians of Pentair and Sta‑Rite pool or spa heaters who need an affordable, direct-fit high-limit replacement. If your heater is tripping or you’ve identified a failed high-limit sensor, the Funmit 42001-0063S gives a fast, compatible option to restore safe operation without expensive downtime.