Overview
The Fenwal 27121-0 Detect-A-Fire heat detector is a rate-compensated thermal detector engineered to detect overheat and fire conditions while initiating alarms or triggering suppression system activation. Unlike fixed-temperature or rate-of-rise detectors alone, this unit combines rate compensation to respond accurately to both slow-developing and rapidly growing fires while minimizing false alarms from transient heat fluctuations.
Key Features
- Rate-compensated design distinguishes real fires from nuisance heat transients
- Hermetically sealed stainless steel shell for corrosion resistance in demanding industrial environments
- Factory preset to specific temperature rating; self-restoring and fully repeatable
- Normally Open (N/O) contacts close on temperature rise when set point is reached
- Multiple contact rating options support diverse suppression system wiring configurations
- ½-14 NPT threaded vertical mount for junction box or conduit installation
Technical Specifications
- Contact Rating: 5A @ 125VAC; 0.5A @ 125VDC; 2A @ 24VDC; 1A @ 48VDC
- Mounting Type: Vertical, ½-14 NPT male thread brass fitting
- Contact Configuration: Normally Open, closing on rise
- Internal Contacts: Hermetically sealed, stainless steel housing
- Insulation Voltage Rating: 1500 Vac (IEC 60947-1, 60947-5-1)
- Lead Configuration: Four (4) wire leads with supervised wiring support
- Weight: Approximately 110 grams
- Certifications: UL, ULC, FM Listed
- Explosion Proof Classes: Class I Groups B, C, D; Class II Groups E, F, G
Typical Applications
- Industrial facilities and manufacturing plants
- Engine compartments in vehicles and equipment
- Paint spray booths and volatile chemical storage areas
- Gas station islands and fuel dispensing locations
- Power generation facilities and electrical equipment enclosures
- Commercial buildings requiring thermal protection
- Fire suppression system activation (clean agent, COâ‚‚, inert gas, wet chemical, dry chemical)
Compatibility & Replacements
Compatible With
- Fire suppression control panels and alarm circuits
- Clean agent, COâ‚‚, inert gas, and dry chemical systems
- Hazardous location electrical enclosures (Class I & II rated installations)
- Standard 4″ octagonal electrical boxes and conduit systems
- Supervised wiring fire alarm networks
Replaces / Drop-In Replacement For
- Other Fenwal 27121 series models with matching temperature rating
- Legacy Detect-A-Fire vertical mount detectors in equivalent temperature classes
- Note: Temperature rating must match original specification; available in 140°F, 160°F, 190°F, 210°F, 225°F, 275°F, 325°F, 360°F, 450°F, 500°F, 600°F, and 725°F variants
Works With
- Standard fire alarm monitoring and control systems
- Supervised relay circuits and hardwired suppression logic
- Common industrial fire detection protocols and wiring standards
- Building fire suppression system integration
