Difference Between Manual Pull and Key Switch

This article will explain differences between Manual Pull and Key Switch which both are normally found in fire protection system. Both are used to trigger CO2 cylinders to release gas into the protected area.

Manual Pull

1. Manual pull is mechanically operated device used to activate CO2 cylinders. There is a handle and wire rope connecting handle and solenoid valve. By pulling the handle, solenoid valve will be mechanically operated to release CO2 gas.
2. When operated, there is no pre alarm, no second alarm, no fire curtain drop and no ringing at alarm bell. 
3. That the reason, manual pull is considered secondary back up in case of automatic system (heat and smoke detector) is not functioning during fire.

Manual Key Switch

1. Key switch is electrically operated device used to activate CO2 cylinders. By turning the button clockwise or pressing the button, electrical signal will be sent to solenoid valve to activate CO2 cylinders.
2. When operated, electrical signal will be sent to CO2 panel.
3. Key switch is considered primary back up in case of automatic system (heat and smoke detector) is not functioning during fire.

Manual Key Switch

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