Genuine Pentair 42002-0025S 140°F Automatic Gas Shut (AGS) Switch for MasterTemp 125 Heaters
Ensure the safety of your compact heating system with the genuine OEM Pentair 42002-0025S Automatic Gas Shut (AGS) Switch. This specialized high-limit sensor is engineered exclusively for the Pentair MasterTemp 125 pool and spa heater models. The AGS acts as a crucial thermal safety device, automatically stopping the gas flow to the burner if internal temperatures within the heat exchanger reach a critical 140°F (60°C). Constructed with durable materials for longevity in outdoor environments, this non-resettable thermal fuse is an essential replacement part to prevent overheating, protect your equipment, and maintain a safe pool experience.
Key Features
- Specific Compatibility: Designed exclusively for use with the Pentair MasterTemp 125 (NG and LP) model heaters. Note: Not for use with 250/300/400 models.
- Critical Safety Device: Automatically shuts off the gas supply to the heater if the water temperature reaches or exceeds 140°F (60°C), preventing dangerous overheating.
- Non-Resettable Design: This is a thermal fuse-style, non-resettable switch that must be replaced after being triggered by an overheat event.
- Durable Construction: Made from quality, corrosion-resistant materials for reliable operation in humid, outdoor pool environments.
- OEM Quality: A genuine factory-authorized Pentair replacement part ensures a perfect fit, reliable performance, and proper system function.
- Easy Installation: Features a simple, thread-mount design for quick and hassle-free replacement.
- Prevents Damage: Protects the heat exchanger and other internal components from the significant damage caused by excessive heat exposure.








