STI (SS2221HV-EN) “key-to-reset ; turn-to-reset ; key-to-activate ; momentary” ; yellow ; hvac shut-down

The STI SS2221HV-EN is a yellow, indoor-only, flush-or-surface Stopper Station with an “HVAC SHUT DOWN” label in English. First, an occupant lifts the protective cover. Then they turn the activation cap to engage the contact and shut down the HVAC circuit. As a result, the connected HVAC contactor or relay drops out without an automated trigger.

What the STI SS2221HV-EN is built for

Smoke control, IAQ events, and gas leaks sometimes require an immediate, manual HVAC shutdown. However, fire alarm pull stations are the wrong control for these scenarios because they trip the building alarm. Therefore, the SS2221HV-EN provides a dedicated, color-coded, labeled switch that drops the HVAC system without engaging fire-alarm initiation.

Verified STI SS2221HV-EN specifications

• Series: STI Stopper Station SS2000 family — SS2221 base = yellow, indoor only, flush or surface mount, turn-to-reset
• Color: Bright yellow housing with “HVAC Shut-Down” lettering in bright white
• Button: Bold red push button with “Push” in bright white for clear activation cue
• Reset: Turn-to-reset (operator rotates the cap to reset)
• Mounting: Flush or surface; indoor only
• Label: “HVAC SHUT DOWN” in English
• Cover: Clear polycarbonate protective cover with unique curved design to prevent accidental activation
• Contacts: Interchangeable N.O. or N.C. SPST gold-plated contact blocks
• Contact rating: 6 A @ 600 VAC; 1 A @ 250 VDC
• Listing: UL Listed to U.S. and Canadian safety standards; complies with UL 2017
• Material: Polycarbonate with stainless steel backplate; 5VA flammability rating
• Operating range: Polycarbonate working properties -40° to 250°F (-40° to 121°C)
• Compliance: ADA Compliant push button
• Warranty: Three-year guarantee against polycarbonate breakage in normal use; one year on electro-mechanical and electronic components

Where SS2221HV-EN fits in the SS2221 family

The SS2221 base ships in several reset configurations. Specifically, key-to-reset, turn-to-reset, key-to-activate, and momentary variants are all available. Furthermore, the label suffix changes the application — HV for HVAC SHUT DOWN, PO for EMERGENCY POWER OFF, EM for EMERGENCY, ES for EMERGENCY STOP. As a result, the SS2221HV-EN is specifically the HVAC shutdown variant.

Application context

HVAC shutdown stations are common in laboratories, kitchens, server rooms, and process facilities. In addition, code-mandated smoke-control sequences sometimes call for a manual HVAC drop-out at the protected space. However, the SS2221HV-EN is indoor only — for weather-exposed installations, specify an outdoor-rated SS2000 variant. Also, this station is not a fire alarm initiating device.

Need help selecting the right part or verifying compatibility? Our team supports thousands of commercial fire alarm installations every year. Call us at 1-888-557-0558 or email sales@lifesafetycom.com for application guidance, lead-time updates, or volume pricing.