If your gas water heater fails to light or heat, a 750 mV thermopile often causes the issue. This guide highlights five compatible thermopile replacements ideal for Whirlpool, A.O. Smith, Reliance, Kenmore, American Water Heater, and similar models. The top picks are selected for reliability, compatibility with common gas valve interfaces, and clear indications of best use cases for different heater configurations. Use the quick reference table to compare options before buying.
| Product | Brand | Best For | Key Compatibility |
|---|---|---|---|
| 750 Mv 100112328 Thermopile | Aekops Store | Whirlpool, American Water Heater, and many 6911197/9007872005 compatible units | 21 inches; 750 mv; Honeywell gas valve interface |
| MENSI Milivolt Thermopile Replacement | MENSI Store | Whirlpool, American Water Heater, AO Smith series | Multiple Whirlpool/N30S61-303 to 50T6-40NG family |
| Upgrade 100112330 Water Heater Pilot Assembly | Pulaim Store | Reliance, Whirlpool, AO Smith, American, Kenmore | Compatible with 300 301 series; 1100112330/9007876/9007877 |
| SP21058 SP20824 Pilot Assembly | Amazon | Rheem, Ruud, Richmond brands; multi-model NG | Thermopile included; supports SP20824/SP20754/SP21058 |
| 750mv Thermopile Sensor Assembly | XDDPRO Store | Rheem, Ruud, Richmond water heaters | SP20824/SP20754/SP21058/SP20800/SP21096/SP20739 |
Note: This table summarizes the five options and highlights their typical compatibility. Always verify your exact model number and valve interface before purchasing.
750 Mv Thermopile Compatible With Multiple Brands
Best for: Homeowners replacing a thermopile in a variety of gas water heaters that use a 750 millivolt output and Honeywell-type gas valve interfaces. This unit lists compatibility with 6911197, 9007872005, 100094024, and 100112327, and it is a practical choice when several related models are in use around the house. It is not compatible with some Reliance C3FVIR or C3FAIR units, so verify model numbers before ordering. This thermopile aims to re-ignite the heater efficiently after replacement.
Why chosen: It covers common 750 mV systems and aligns with many standard valve interfaces, making it a versatile option for mixed-brand installations. Caution: Confirm compatibility with your exact model to avoid mismatches with Reliance C3 variants.
MENSI Milivolt Replacement Thermopile
Overview
Best for: Whirlpool, AO Smith, and American Water Heater models within the N30/N40/N50 series families. The listed compatible models include N30T61-303, N40T61-403, N50T62-403, N40T121-403, and more, allowing a broad range of standard gas water heater configurations. This makes it a solid pick for tradespeople and DIYers with multiple heater brands in one home.
Why chosen: The product spans multiple compatible brands and model lines, reducing the number of separate parts needed for a household with mixed units. Caution: Verify exact model compatibility due to minor size variations among similar thermopiles.
Upgrade 100112330 Pilot Assembly
Best for: Reliance, Whirlpool, AO Smith, Kenmore, State, American Water Heaters. This assembly replaces 100112330 and related parts like 9007876 and 9007877, addressing issues where the indicator light fails to light or the heater fails to heat due to thermocouple problems.
Why chosen: It provides a direct replacement path for several common part numbers, simplifying sourcing. Caution: Ensure the exact part number matches your heater’s original component to avoid fit issues.
SP21058 SP20824 Pilot Assembly with Thermopile
Best for: Rheem, Ruud, and Richmond water heaters. The kit supports multiple models (SP20824, SP20754, SP21058, SP20800) and includes a sparker and thermopile. This is ideal for multi-brand households or service technicians managing varied units.
Why chosen: It bundles essential components for ignition, ensuring robust compatibility across several brands. Caution: This kit uses an electrical thermocouple connection, so verify your heater’s connector type before ordering.
750mv Thermopile Sensor Assembly
Best for: Rheem, Ruud, Richmond gas water heaters. It’s designed to deliver a stable 750 mV output and supports various replacement options across the SP20824, SP20754, SP21058, SP20800, SP21096, and SP20739 families.
Why chosen: This sensor assembly emphasizes stability and compatibility with common burner and valve interfaces, helping avoid ignition failures. Caution: Confirm model-by-model compatibility as interface connectors can vary between units.
Buying Guide
How to choose the right thermopile for your water heater
- Check voltage output: Most residential gas water heaters use a 750 mV thermopile. Confirm your unit’s required output before purchasing.
- Verify gas valve interface: Some thermopiles are designed for Honeywell-type interfaces. Ensure your valve type matches the product specification.
- Model number compatibility: Cross-check model numbers (e.g., 6911197, 9007876, 9007877, 100112327, etc.) listed in product notes to prevent fit issues.
- Brand and series compatibility: If your heater is a Whirlpool, AO Smith, American Water Heater, Kenmore, Reliance, or Rheem/Ruud/Richmond unit, select a thermopile designed for those brands or a broad-compatibility kit.
- Inclusion of supporting components: Some kits include sparker, pilot assembly parts, or LP/Natural gas adapters. Choose based on whether you need a full ignition assembly or just the thermopile sensor.
- Caution on fuel type and installation: Some parts are not compatible with propane units. Confirm propane vs. natural gas compatibility before ordering.
What to consider when comparing options
- Compatibility breadth: A milivolt thermopile that covers many model families reduces the number of replacements needed.
- Physical size and length: Ensure the replacement length (for example, 21 inches) matches your current setup to avoid misfit.
- Installation complexity: Some options are single-component thermopiles, while others are complete pilot assemblies. Choose based on your comfort level with installation.
- Reliability signals: Look for products that emphasize corrosion resistance and stable voltage output to minimize future failures.
- Access and warranty: Availability through major retailers and clear return policies can simplify post-purchase support.
FAQ
- What is a thermopile in a water heater? A thermopile generates a small electrical current from the flame to keep the gas valve open during ignition.
- How do I know if my thermopile is bad? Symptoms include a lack of ignition, the pilot light failing to stay lit, or the heater not heating as expected.
- Can I replace just the thermopile or do I need a full pilot assembly? If your burner includes a sparker or other ignition components, a full pilot assembly may be necessary; otherwise, a single thermopile might suffice.
- Are these thermopiles universal? They are not universal; verify model numbers, brand, gas valve interface, and voltage requirements before buying.
- Is it safe to replace a thermopile myself? Replacing a thermopile involves gas and electrical components. Only perform repairs if you are confident in safe, correct installation following manufacturer guidelines.
- Do these parts work with propane or natural gas? Some parts are designed for natural gas and may not be compatible with propane units. Check gas type compatibility in the product notes.