45° 1/8" AGS Sensor For Pentair Mastertemp, Waterco Turbotemp, Sta-Rite Max-E-Therm Gas Pool & Spa Heaters - 200 / 300 / 400 HD models. This is located at the top of the water manifold on the top left. Not all heaters used these. This is not the common 1/4" threaded AGS sensor. Number 6b on diagram.

Pentair Mastertemp / Waterco Turbotemp Electrical Parts List:

• 2. / 3. / 4. Igniter & Gasket Kit
• 5. AGS Switch 60°C / 140°F
• 6. HLS Switch 55°C / 131°F
• 6b. 45°C Switch
• 7. Thermistor / Temperature Sensor
• 10. Ignition Control Module
• 12. Air Flow Switch
• 13. Main PCB / Control Panel 
• 15. Touchpad Membrane
• 16. SFS Sensor

For other Pentair Mastertemp / Waterco Turbotemp spare parts, click the correct category below:

• Pentair Mastertemp Gas Heater Spare Parts - Water System
• Pentair Mastertemp Gas Heater Spare Parts - Burner System

Pentair Mastertemp, Waterco Turbotemp, StaRite Max E Pro Error Codes: 
Diagnostic LEDs / Error Messages & Causes:

• PS - Check / Replace Pressure Switch. Signifies flow issues.
• HLS - Check / Replace High-Limit Switch/es (faults above 45°C or 55°C) Signifies flow, bypass, governer issues, or other issues.
• AFS - Check / Replace Air Flow Switch. Signifies fan, air flow, or other issues.
• AGS - Check / Replace AGS Automatic Gas Shutoff Switch/es (faults above 60°C). Signifies flow, bypass, governer issues, or other issues. Can also be caused by a 45° Limit Switch on top of the manifold.
• SFS - Check / Replace SFS Stack Flue Sensor (faults above 249°C). High or Low Flue Temperatures are a sign of significant combustion issues, or other issues.
• E01 - Thermistor Fault. Replace Thermistor.
• E05 - General Fault. Needs service. This can be caused by several issues.
• Showing Incorrect Temperature - Replace Thermistor. Check all filters clean. If thermistor shows corrosion, water balance is poor.