Pentair Automatic Gas Shutoff Switch (AGS) | MasterTemp & Max-E-Therm Heaters | 42002-0025S
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- SKU:
- 42002-0025S
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About This Item
The Pentair Automatic Gas Shutoff Switch (AGS) (42002-0025S) is the OEM replacement safety switch for Pentair MasterTemp and Max-E-Therm 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.
IMPORTANT: QUANTITY REQUIRED PER SYSTEM — VERIFY BEFORE ORDERING
When used as part of the MasterTemp / Max-E-Therm Heater Master Kit assemblies (461100, 461101, 461102), 2 units of this switch are required per system. For direct heater replacement (MasterTemp 125, Max-E-Therm), 1 unit is required. Confirm the quantity needed against your equipment's service manual before ordering.
The Automatic Gas Shutoff Switch (AGS) is a safety-critical component that interrupts gas flow to the burner assembly when an unsafe operating condition is detected. A failed or degraded switch can prevent the heater from firing — or, more critically, compromise the heater's ability to cut gas supply under fault conditions. Replacing this component with the OEM part ensures the heater maintains the safety performance it was engineered and certified to deliver.
Specifications
| Pentair Part Number | 42002-0025S |
| Part Name | Automatic Gas Shutoff Switch (AGS) |
| Part Category | Switches |
| Quantity Included | 1 (Each) |
Fits Into
| Brand | Equipment Line | Model / Part Number | Notes |
| Pentair | MasterTemp | MT125 | 1 required per unit |
| Pentair | MasterTemp | MasterTemp125 | 1 required per unit |
| Pentair | Max-E-Therm | MAX-E-THERM | 1 required per unit |
| Pentair | MasterTemp / Max-E-Therm | 461102 — Heater Master Kit (Water) | 2 required; included in all three master kits |
| Pentair | MasterTemp / Max-E-Therm | 461100 — Heater Master Kit (All) | 2 required; included in all three master kits |
| Pentair | MasterTemp / Max-E-Therm | 461101 — Heater Master Kit (Electrical) | 2 required; included in all three master kits |
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.
Poolaroo Pro Tip
Before ordering, locate the part number stamped or printed on your existing shutoff switch and confirm it reads 42002-0025S. Both the MasterTemp and Max-E-Therm lines share components across multiple BTU configurations — always verify against the installed part or the heater's service manual. When your technician has the heater out of service for this repair, it is good practice to have them inspect the adjacent gas valve, pressure switch, and ignition wiring for signs of wear. Replacing a single failed safety component is the right moment to assess the surrounding assembly.
