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Wired + Wireless interconnected smoke alarms HM-638PHW HM-638PHW-AC

The Heiman HM-638PHW wireless interconnected and HM-638PHW-AC wired + wireless interconnected smoke alarms are equipped with a 10-year battery backup and utilise Heiman’s advanced, precision-calibrated sensor technology, complying with the latest industry standards. These devices allow multiple alarms to be interconnected, providing early warning throughout the home, whilst the 10-year battery backup ensures continuous protection in the event of a power cut, giving you complete peace of mind.

SPECIFICATION

Model	HM-638PHW-AC	HM-638PHW
Power Supply	220–240V~ (50Hz, 1.2W MAX)	DC 3V, Built-in 10-Year Battery
Battery Life	Built-in 10-Year Battery Backup	10-Year Battery Backup
Transmit Power	5.7 dBm	5.7 dBm
Wireless Frequency	868 MHz	433 MHz
Radio Pro～col	SRD	SRD
Sound Level	≥85 dB (at 3 m)	≥85 dB (at 3 m)
Operating Temperature	0 °C ～ +50 °C	0 °C ～ +50 °C
Operating Humidity	≤95% RH (Non-condensing)	≤95% RH (Non-condensing)
Wireless Interconnection	Up ～ 40 Alarms Maximum	Up ～ 40 Alarms Maximum
Wired Interconnection	Up ～ 20 Alarms over 250 m Maximum	Up ～ 20 Alarms over 250 m Maximum
Dimensions	L125 mm × W125 mm × H46 mm	L125 mm × W125 mm × H46 mm
Certification	CE、BSI、UKCA、RCM、AS 3786	CE、BSI、UKCA、RCM、AS 3786

Wired or Wireless Interconnection

Select wired-plus-wireless or wireless-only mode.
Works in homes with or without wiring.
Link multiple units for whole-home alerts.
Expand coverage across rooms and floors.
Perfect for new builds and retrofits.
Customize your safety network freely.
Early Warning Detection

Advanced sensing technology detects smoke rapidly.Provides precious extra time for safe evacuation.Reliable photoelectric sensor reduces false alarms.Guards your family with responsive fire detection.
10-Year Sealed Backup Battery

Sealed lithium battery provides decade-long backup power.Protects your home even during electrical outages.Eliminates frequent battery replacement hassles.Long-lasting reliability for continuous safety coverage.
Oversized Button for Easy Test & Hush

Large, easy-press button for effortless testing and silencing.Quickly hush false alarms with a single touch.Convenient for users of all ages, including seniors.Simplify daily operation while ensuring reliable protection.
End-of-Life Reminder

Automatic alert when the alarm reaches lifespan limit.
Ensures timely replacement for uninterrupted safety.
Never guess when your device needs upgrading.
Stay protected with proactive maintenance reminders.

HM-636,638 series DECLARATION OF PERFORMANCE(BSI certificated)：https://www.heimantech.com/product/common/upload/2026/11/10/20261110104522T5.pdf

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Wired + Wireless interconnected smoke alarms HM-638PHW HM-638PHW-AC

Wired or Wireless Interconnection

Early Warning Detection

10-Year Sealed Backup Battery

Oversized Button for Easy Test & Hush

End-of-Life Reminder

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