Honeywell ST7800A Plug-In Purge Timer Card

Models: ST7800A1104 / ST7800A1005 / ST7800A1054 / ST7800A1039 / ST7800A1021 / ST7800A1088 / ST7800A1070

1. Product Overview

The Honeywell ST7800A Series Plug-In Purge Timer Cards are timing modules designed for selected Honeywell 7800 Series Burner Control / Flame Safeguard Relay Modules. Their main function is to establish the required prepurge time before the burner ignition sequence begins.

During prepurge, combustion air is introduced into the combustion chamber to help clear residual fuel before ignition. Different ST7800A models provide different fixed prepurge periods, allowing the burner control system to match the requirements of different combustion equipment. Honeywell's official documentation identifies the ST7800A series as plug-in purge timers for selected 7800 Series relay modules.

The seven models in this listing cover prepurge times from 2 seconds to 9 minutes, making them suitable for a wide range of industrial and commercial burner applications.

2. Key Features

• Original Honeywell 7800 Series purge timer
• Plug-in installation design
• Fixed and precise prepurge timing
• Designed for selected 7800 Series burner controls
• Helps establish safe combustion chamber ventilation
• Simple replacement and maintenance
• Multiple timing options available
• Reliable operation in burner management systems
• Suitable for industrial gas and oil burner applications
• UL, CSA and Factory Mutual approvals for the ST7800 series

3. Technical Specifications

Brand: Honeywell

Product Series: ST7800A

Product Type: Plug-In Purge Timer Card

Application: 7800 Series Burner Control / Flame Safeguard System

Main Function: Prepurge Timing

Installation: Plug-in type

Timer Type: Fixed Prepurge Timer

Application: Gas Burner / Oil Burner / Industrial Combustion System

The available models and their corresponding prepurge times are:

ST7800A1005
Prepurge Time: 2 seconds

ST7800A1021
Prepurge Time: 10 seconds

ST7800A1039
Prepurge Time: 30 seconds

ST7800A1054
Prepurge Time: 60 seconds / 1 minute

ST7800A1070
Prepurge Time: 2.5 minutes

ST7800A1088
Prepurge Time: 4 minutes

ST7800A1104
Prepurge Time: 9 minutes

These timing values are listed in Honeywell's official ST7800A/C technical documentation.

4. Model Comparison

ST7800A1005 — 2 Seconds

The shortest prepurge option in this group. Designed for burner systems requiring a short, fixed prepurge period.

ST7800A1021 — 10 Seconds

Provides a 10-second prepurge and is commonly used where a longer purge period than the 2-second version is required.

ST7800A1039 — 30 Seconds

Provides a 30-second prepurge for burner systems requiring standard combustion-chamber ventilation.

ST7800A1054 — 60 Seconds

Provides a 1-minute prepurge and is suitable for applications requiring additional chamber ventilation before ignition.

ST7800A1070 — 2.5 Minutes

Provides a 2.5-minute prepurge for burner systems with longer purge requirements.

ST7800A1088 — 4 Minutes

Provides a 4-minute prepurge for applications requiring extended chamber ventilation.

ST7800A1104 — 9 Minutes

Provides a 9-minute prepurge and is designed for burner applications requiring a substantially longer purge period.

Honeywell's catalog confirms the progression of these seven models from 2 seconds, 10 seconds, 30 seconds, 60 seconds, 2.5 minutes, 4 minutes, to 9 minutes.

5. Compatible System

The ST7800A is designed to work with selected Honeywell 7800 Series relay modules. The purge timer is installed directly into the designated purge-timer compartment of the relay module.

The correct ST7800A model must be selected according to the required prepurge time and the specific 7800 Series burner control configuration. Honeywell specifically instructs users to verify the desired timing period before installing the replacement timer.

6. Applications

The Honeywell ST7800A Purge Timer Cards are suitable for:

• Industrial gas burners
• Oil burner systems
• Industrial boilers
• Furnace burner systems
• Heating equipment
• Thermal processing equipment
• Industrial ovens
• Drying systems
• Process heating systems
• Burner management systems

7. Advantages

The ST7800A Series provides a convenient way to configure the prepurge period of compatible Honeywell 7800 burner control systems.

Different fixed-time modules allow engineers to select the appropriate purge duration without replacing the complete burner relay module. The plug-in construction also simplifies installation, replacement, and maintenance.

With seven timing options in this listing, users can select the appropriate module according to the original system configuration and required burner purge sequence.

8. Why Choose Us

• Original Honeywell industrial combustion products
• Multiple ST7800A models available
• Stable stock availability
• Competitive pricing
• Professional burner control technical support
• Fast worldwide shipping
• OEM and bulk order support

9. Packaging & Delivery

Standard export packaging is used to protect the purge timer card during transportation.

Stock items can be dispatched quickly by international express, air freight, or other suitable shipping methods.

10. Inquiry Now

If you are looking for Honeywell ST7800A1104, ST7800A1005, ST7800A1054, ST7800A1039, ST7800A1021, ST7800A1088, or ST7800A1070 Plug-In Purge Timer Cards, we can provide competitive pricing, technical information, and availability.

Important: These models are not interchangeable solely based on physical appearance. The prepurge timing must match the original burner system specification before replacement.