GS509A-2NCDR
Siterwell Smoke & Carbon Monoxide Detectors
An independent photoelectric smoke alarm with a replaceable 9V battery โ tested to UL 217 and CAN/ULC S531, with a 10-year product life.
UL 217, 9th Edition
Responsive Detection
3-Year Limited Warranty
GS366A-MWAC
Smart Thermostat
Recognized for thoughtful design,
intuitive control, and a smarter
home comfort experience.
2026 IDEA FINALIST
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UL 217 smoke alarms, UL 2034 carbon monoxide alarms
Siterwell is a home safety manufacturer making photoelectric smoke detectors, carbon monoxide alarms and combination units. Smoke-only alarms are tested to UL 217, carbon monoxide alarms to UL 2034, and combination units to both; check each product page for the certifications that model carries.
Frequently Asked Questions
Will steam or cooking set off my Siterwell alarm?
Cooking fumes, steam, dust and insects may cause false alarms in smoke alarms; car exhaust or certain chemicals may cause false alarms in carbon monoxide alarms. Our combination alarms use SMART Silence control to temporarily quiet nuisance alarms. All models should be installed away from kitchens and bathrooms where possible.
What kind of smoke do photoelectric alarms detect?
Our smoke alarms use photoelectric or multi-criteria optical sensing to reliably detect combustion particles from both smoldering and fast-flaming fires.
Where should I install a smoke and carbon monoxide alarm?
Smoke alarms should be installed on the ceiling, at least 4 in (10 cm) from side walls and away from fluorescent lights. Carbon monoxide alarms should be mounted at least 6 ft (1.8 m) above the floor and at least 5 ft (1.5 m) away from heating or cooking appliances โ 15 ft is recommended to reduce nuisance alarms.
How often should I test my smoke alarm?
We recommend testing the alarm function once a week, according to the user manual. At the same time, the dust on the alarm surface should be cleaned every month to ensure the sensitivity of the sensor.
Does the battery need to be replaced?
It depends on the model. Some alarms use a built-in lithium battery that lasts the life of the unit; others use a replaceable 9V or AA battery, and the alarm will alert you when it needs changing. Check your model's product page for the battery type.
Is Siterwell a legitimate manufacturer?
Our smoke and carbon monoxide alarms are sold through this official Siterwell store. Each product page lists the certifications that model carries, and you can contact our support team for product documentation.
What certifications do Siterwell alarms carry?
Smoke-only alarms are tested to UL 217; carbon monoxide alarms to UL 2034; combination units to both. Certification details vary by model โ check the product page or the manual for the specific listing.