Best Gas Heater Sensors and Safety Replacement Parts

Choosing the right sensor for a gas heater affects safety, performance, and reliability. This guide compares five reliable replacement sensors and safety switches for residential and recreational gas heaters, water heaters, dryers, and pool heaters. Below is a quick summary table of the selected products for easy comparison.

Product	Type	Key Compatibility	Primary Function
SP20172 Flammable Vapor FV Sensor Kit	Flammable Vapor Sensor	Rheem/Ruud/Richmond, select AO Smith/Bradford White	Detects gasoline vapors and shuts off gas
Pentair 42002-0025S 140F AGS Switch	Automatic Gas Shutoff (Temperature)	Pentair Sta-Rite Max-E-Therm SR200/SR333/SR400	Shuts gas when temperature exceeds 140°F
Water Flow Sensor Compatible With CAMPLUX (VATTCEEL)	Water Flow Sensor	CAMPLUX, Ranein, Recpro, Girard, FOGATTI, Furrion RV heaters	Detects water flow to enable gas burner / tankless control
Hayward IDXLFLS1930 Flame Sensor Replacement	Flame Sensor (Pool/Water Heater)	Hayward Universal H-Series Induced Draft and Gas Heater	Detects flame presence for ignition safety
Upgraded 338906 Gas Dryer Flame Sensor (Sikawai)	Appliance Flame Sensor	Whirlpool, Kenmore, Roper, many dryer models	Monitors dryer burner flame to prevent gas flow if no flame

SP20172 Flammable Vapor FV Sensor Kit | AP13447-3 – 25VS

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This kit from Holdly includes a Flammable Vapor Sensor (AP13447-3 – 25VS), a cap plug, and a wire tie. It is built to detect gasoline and other flammable vapors inside the water heater enclosure and trigger a control module to cut gas supply.

• Compatibility: Designed for Rheem, Ruud, Richmond FVIR water heaters and select AO Smith and Bradford White models.
• Operation: Uses a sensor film whose resistance changes rapidly when exposed to gasoline vapors, enabling quick detection and shutdown.
• Safety Role: Intended to reduce the risk of ignition by shutting off gas when flammable vapors are present.
• Kit Contents: Sensor element, cap plug, wire tie for secure installation.

For installations that require FVIR (Flammable Vapor Ignition Resistant) components, this replacement sensor addresses the specific hazard of liquid fuel vapors pooling near the heater. Verify model compatibility before ordering to ensure the AP13447-3 matches your heater’s control system.

Pentair 42002-0025S Replacement 140F Automatic Gas Shutoff (AGS) Switch

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The Pentair 140°F AGS switch is a temperature-actuated gas shutoff device intended for pool and spa heater systems. When temperatures rise beyond its setpoint, the switch interrupts gas flow to prevent overheating.

• Compatibility: Direct replacement for Pentair Sta-Rite Max-E-Therm models SR200, SR333, SR400.
• Function: Automatic gas shutoff at 140°F to prevent equipment overheating and associated hazards.
• Construction: Engineered for humid, chemical-exposed pool environments with durable materials and stable sensor response.
• Support: Supplied with a 12-month warranty and USA support per listing features.

This AGS switch is a safety-focused sensor combining a mechanical/electrical cutoff triggered by temperature. It is primarily applicable to specialized pool and spa heater systems rather than residential space heating equipment.

Water Flow Sensor Compatible With CAMPLUX Ranein Recpro Girard FOGATTI Furrion

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This VATTCEEL water flow sensor is specified for RV and tankless gas water heaters. It detects water motion to enable or disable the gas burner, providing essential flow detection for on-demand heating systems.

• Compatibility: Works with CAMPLUX, Ranein, Recpro, Girard, FOGATTI, Furrion and other tankless RV water heaters.
• Primary Role: Senses water flow to start the burner and ensure the heater only fires when water demand exists.
• Quality Control: Product undergoes factory testing and includes a 12-month responsiveness warranty as listed.
• Installation: Typical inline mounting on the cold-water inlet; confirm fit and thread size for your model prior to installation.

Flow sensors for tankless systems are critical to safe combustion control. A failing sensor can cause no-heat conditions or unsafe burner operation, so confirm electrical connector compatibility and flow threshold specs for your heater.

Hayward IDXLFLS1930 Flame Sensor Replacement For Hayward H-Series

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The Hayward IDXLFLS1930 flame sensor is intended for Hayward Universal H-Series low-NOx induced draft and gas heaters. It senses the presence of burner flame to permit continuous gas delivery during operation.

• Compatibility: Fits multiple H-Series models including H150FDN/H150FDP through H350/400 variants listed.
• Function: Flame detection for ignition safety and to prevent gas flow if flame is absent.
• Application: Commonly used in pool heaters and similar gas-fired systems employing induced draft ignition.
• Materials: Constructed for rapid ignition sensing and stable long-term service in heater environments.

Flame sensors are a core safety element preventing unburned gas accumulation. When replacing, ensure the sensor length and mounting orientation match the original to maintain reliable flame sensing performance.

Upgraded 338906 Gas Dryer Flame Sensor Fits Whirlpool Kenmore Roper

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This Sikawai replacement flame sensor is positioned for gas dryers and replaces common OEM numbers like WP338906, AP6008294 and PS11741429. It senses the burner flame and prevents gas flow if ignition fails.

• Compatibility: Matches a wide list of appliance models and OEM part numbers across Whirlpool, Kenmore, Roper and related brands.
• Installation Notes: Listing includes guidance to disconnect power before servicing and to verify model compatibility before ordering.
• Function: Monitors dryer burner flame continuity; typical use is to protect against unburned gas and repeated ignition attempts.
• Replacement Fit: Intended as a drop-in substitute for the referenced OEM part numbers when dimensions align.

Appliance flame sensors are typically straightforward to replace, but they must match the original in length, probe diameter, and connector type. Follow safe servicing practices and verify electrical isolation before touching components.

Buying Guide: How To Choose The Right Gas Heater Sensor

Selecting a sensor for a gas heater involves matching function, compatibility, and environmental tolerance. Below are the key considerations to evaluate across sensor types.

Identify The Sensor Type You Need

• Flame Sensors: Detect presence of flame. Use for ignition verification in heaters and appliances. Required if the control system relies on flame sensing to enable gas valve operation.
• Flow Sensors: Detect water flow for tankless water heaters and RV heaters. Prevents burner firing without water demand.
• Flammable Vapor Sensors (FVIR): Detect combustible liquid vapors inside the heater compartment and trigger a shutoff to prevent ignition.
• Temperature Shutoff Switches (AGS): Trigger shutoff when temperatures exceed a safe threshold, typically used in pool/spa heaters.

Confirm Model Compatibility

• OEM Part Numbers: Match the OEM number where possible to ensure physical fit and electrical compatibility.
• Heater Control Interface: Check that the replacement sensor communicates with your existing control module (resistance range, connector type, voltage).
• Mounting And Probe Dimensions: Verify length, thread size, and mounting orientation to avoid clearance or sensing location issues.

Assess Environmental And Durability Requirements

• Corrosion Resistance: Pool and spa heaters need sensors resistant to humidity and pool chemicals.
• Temperature Tolerance: Ensure the sensor’s operating temperature range suits your application (e.g., AGS rated at 140°F).
• Vibration And Shock: RV and appliance sensors should withstand mobile service conditions and vibration.

Safety And Certification Considerations

• Regulatory Fit: For safety-critical parts, ensure the replacement either matches OEM safety approvals or is explicitly rated for the intended use.
• Functional Testing: After installation, test the sensor operation per manufacturer or service manual instructions to confirm correct behavior.

Installation And Serviceability

• Professional Installation: For gas appliances and heaters, consider a qualified technician to install and test sensors to maintain safety compliance.
• Electrical Isolation: Always disconnect power and gas before servicing; follow the listed product installation notes.
• Spare Parts And Support: Check vendor warranty and support terms; some listings include a 12-month warranty or USA-based support channels.

Comparison Perspectives

• Function vs. Compatibility: A sensor that performs well but doesn’t fit your control circuit is not a safe replacement. Prioritize parts that match both electrical and mechanical interfaces.
• Durability vs. Cost: Sensors used in harsh environments (pool chemical exposure, mobile RV use) may justify higher-quality materials for longevity and reduced service intervals.
• OEM vs. Aftermarket: OEM parts often provide exact fit and documented compatibility. Quality aftermarket parts can be cost-effective but require careful verification of specs and connectors.

Final Technical Checklist Before Purchasing

1. Confirm the heater or appliance model and original part number.
2. Verify electrical connector type and expected signal/resistance range.
3. Check probe length, thread size, and mounting style match existing part.
4. Assess environmental durability (temperature, humidity, chemicals).
5. Review warranty/support and seller documentation for returns or technical help.