Description
Product Overview
The Holdly Flammable Vapor Sensor (Model HMP6, Part Number 25VS) is a critical safety component designed for gas water heaters. This white sensor measures 1x1x1 inches and weighs just 0.352 ounces, featuring advanced film technology that rapidly reacts to gasoline vapors in the surrounding air. The complete kit includes the flammable vapor sensor, a cap plug, and a wire tie for secure installation. Manufactured by Holdly with part number 25VS, this sensor operates without requiring batteries or external power, drawing minimal energy from the water heater’s control circuit to monitor vapor concentrations and trigger safety protocols when needed.

Usage
This flammable vapor sensor is specifically designed for residential and commercial gas water heater systems, particularly those equipped with FVIR (Flammable Vapor Ignition Resistance) technology. It’s ideal for homeowners, property managers, and professional technicians maintaining Rheem, Ruud, Richmond, AO Smith, and Bradford White water heater models. The sensor activates in environments where gasoline vapors might accumulate near water heater installations, such as garages, utility rooms, or basements where fuel-powered equipment is stored. When vapor concentrations reach potentially dangerous levels, the sensor initiates an immediate safety response to prevent ignition risks.
Why Choose Us
Holdly sensors are engineered with precision materials that ensure consistent performance and reliability in safety-critical applications. The vapor detection film undergoes rigorous testing to guarantee accurate response to gasoline vapors while minimizing false triggers. Unlike generic replacements, this sensor maintains compatibility with original equipment manufacturer specifications, ensuring seamless integration with your water heater’s control system. The product comes with comprehensive after-sales service support and is ranked #21 in Water Heater Replacement Parts, reflecting its trusted performance among professionals and homeowners alike.
Key Features
- Advanced vapor detection film quickly identifies gasoline vapor presence in surrounding air
- Rapid response system triggers gas supply shutoff within seconds of vapor detection
- No external power requirements – operates using minimal control circuit energy
- Direct compatibility with Rheem, AO Smith, and Bradford White water heater models
- Complete installation kit includes sensor, cap plug, and securing wire tie
FAQ
What water heater brands is this sensor compatible with?
This Holdly flammable vapor sensor is compatible with Rheem, Ruud, Richmond, and select models of AO Smith and Bradford White water heaters equipped with FVIR technology. Always verify your specific water heater model requirements before purchase.
Does the sensor require batteries or external power to operate?
No, the sensor operates using the minimal power provided by your water heater’s existing control circuit. It requires no batteries, external power sources, or additional wiring for proper functionality.
How quickly does the sensor respond to gasoline vapors?
The sensor’s specialized detection film provides rapid response to gasoline vapor presence, typically triggering the control module to shut off gas supply within seconds of detection to prevent potential ignition.
What components are included in the installation kit?
The complete kit includes one flammable vapor sensor (AP13447-3 – 25VS), one cap plug for secure connections, and one wire tie for proper mounting and strain relief during installation.
Is professional installation required for this sensor?
While many homeowners with basic technical skills can install the sensor, we recommend consulting your water heater’s installation manual or hiring a qualified technician to ensure proper installation and safety compliance.




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