Siemens MS-501 Double-Action Pull Station P/N:500-620522

The Siemens MS-501 Double-Action Fire Alarm Pull Station provides reliable manual fire alarm activation for compatible conventional fire alarm systems. It features a durable red polycarbonate housing and a two-step activation mechanism. In addition, its resettable design eliminates the need for replacement glass rods after operation.

Double-Action Manual Fire Alarm Activation

The Siemens MS-501 uses a double-action mechanism to help prevent accidental activation. First, the user presses the push-in tab. Then, the pull-down lever becomes accessible.

When the user pulls the lever, the station activates its internal alarm contacts. As a result, the connected fire alarm control panel can recognize the alarm condition.

The lever remains in the activated position until authorized personnel reset the station. Therefore, the device provides visible confirmation of manual operation.

Durable Polycarbonate Construction

The station features a molded polycarbonate housing with a matte red finish. Raised white lettering clearly identifies its fire alarm function.

Moreover, the construction provides resistance to shock and vibration. This design supports dependable operation in compatible commercial and institutional environments.

The station does not require break rods. Consequently, maintenance personnel can reset the device without replacing a glass component.

Electrical Contact Operation

The manual station provides normally open SPST alarm contacts. Siemens specifies a main contact rating of 0.75A at 28 VAC/DC.

The manufacturer also lists an auxiliary normally closed SPST contact with the same electrical rating.

These contacts allow the station to interface with compatible low-voltage fire alarm initiating circuits. However, technicians must verify circuit requirements before installation.

Key Features

• Double-action manual fire alarm pull station
• Siemens manufacturer part number 500-620522
• Non-coded conventional operation
• Push-in tab and pull-down lever
• Normally open SPST main alarm contact
• Normally closed auxiliary contact
• 0.75A at 28 VAC/DC contact rating
• Durable molded polycarbonate housing
• Matte red finish with raised white lettering
• Shock- and vibration-resistant construction
• Visible indication after activation
• Resettable mechanical design
• No replacement glass rods required
• Allen-key reset mechanism
• Surface or semi-flush mounting options
• ADA-compliant operating design
• UL Listed
• FM and CSFM approved

Resettable Fire Alarm Operation

The Siemens MS-501 includes a mechanical locking mechanism that holds the pull-down lever in its activated position.

After an alarm event, authorized personnel can open the hinged housing using the appropriate Allen key. They can then restore the lever and close the station.

This reset procedure returns the mechanical assembly to its normal position. However, technicians must also follow the connected fire alarm control panel’s reset procedures.

Mounting and Installation

The manual station supports surface and semi-flush installation with compatible electrical boxes and mounting accessories.

Its hinged housing connects to a backplate assembly. In addition, an Allen-head locking screw secures the station after installation.

This mounting arrangement provides convenient access for authorized inspection and maintenance.

Typical Fire Alarm Applications

This Siemens double-action pull station supports manual alarm initiation in compatible commercial and institutional buildings.

Typical applications include office buildings, schools, warehouses, industrial facilities, retail properties, and other locations that require manual fire alarm activation.

Furthermore, its two-step operation helps reduce unintended activation from accidental contact with the pull lever.

Installation and Compatibility

Before installation, verify fire alarm panel compatibility, initiating circuit requirements, contact ratings, and mounting configuration.

Installers should also confirm the required mounting height and location according to the approved fire alarm design.

Qualified fire alarm professionals should install, wire, inspect, and test the station. Additionally, technicians should follow Siemens documentation and applicable fire alarm codes.

Overall, this Siemens double-action manual station provides a durable and practical solution for conventional fire alarm systems. Its resettable mechanism, reliable electrical contacts, red polycarbonate housing, and flexible mounting options make it suitable for professional fire alarm installations.

MS-501 Datasheet