7800 Series (EC78xx)
Burner Control Modules
A flexible, modular family of relay-based burner control units for industrial combustion reliability and safety.
What is the Honeywell 7800 Series?
The Honeywell 7800 Series (also known as the 7800 SERIES or EC78xx/RM78xx) is a microprocessor-based integrated burner control system designed for automatically fired gas, oil, or combination fuel single burner applications. It provides safety, functional capability, and features beyond conventional controls, typically reducing downtime by 30-40% through advanced diagnostics.
Unlike fully integrated digital controllers, the 7800 Series uses a modular architecture, allowing system integrators to configure burner control systems by combining a relay module, subbase, amplifier, and purge card according to specific operational needs.
How does the 7800 Series work?
The 7800 Series functions by sequencing the burner motor, ignition, and fuel valves while continuously monitoring the flame via UV, IR, or rectification flame detectors. It enforces a safe start check, pre-purge, pilot ignition, main flame establishment, and post-purge phases.
7800 Series burner control modules are widely applied in:
- Industrial boilers and steam generators
- Process furnaces and thermal equipment
- Gas, oil, and dual-fuel burner systems
- Industrial combustion systems requiring modular safety logic
Key Differences
Modular Architecture & Differentiation
The Honeywell 7800 Series differs from traditional fixed-logic controllers through its interchangeable plug-in modules. Key differentiating components include:
- Relay Modules: The core logic controller (e.g., EC7820, RM7840). Options exist for On-Off, High-Low, or Modulating control logic.
- Flame Amplifiers: Plug-in cards matching the specific flame detector type (UV, IR, Rectification, or Optical).
- Purge Timers: Selectable timing cards ranging from 2 seconds to 30 minutes to meet specific NFPA, UL, or CE purge requirements.
- Keyboard Display Module (KDM): An optional diagnostic interface (S7800A) providing 6 rows of 20 characters for first-out annunciation, reducing troubleshooting time significantly.
This modular design allows precise adaptation to different industrial burner configurations while simplifying maintenance, as individual components can be replaced without rewiring the entire system.
Applications
- Industrial boilers & steam generators
- Process furnaces & thermal equipment
- Gas, oil, and dual-fuel burners
- Modular relay logic requirements
- Safety supervision retrofits
Model Comparison
7800 Series Model Overview
| Model | Control Type | Key Function |
|---|---|---|
| EC7820A1026 | Relay Control | Primary burner sequencing |
| EC7823A1004 | Flame Relay | Flame detection and supervision |
| EC7830A1033 | Relay Control | Standard industrial burner control |
| EC7840L1014/U | Modulating Relay | Modulating burner applications |
| EC7850A1072/U | Relay Control | Advanced diagnostics |
| EC7850A1122/U | Safety Relay | Safety-focused burner control |
| EC7890B1028/U | Relay Control | Automated fuel systems |
| EC7895C1000/U | Relay Control | Integrated safety logic |
Standard Relay Control
Typically used for standard relay-based burner control.
Modulating Control
Preferred for modulating burner systems.
Safety & Diagnostics
Selected for applications requiring enhanced diagnostics or safety logic.
Frequently Asked Questions
What is the difference between EC7800 and RM7800 series?
The primary difference is the operating voltage. The EC7800 series operates on 220-240 VAC, making it standard for European and Asian markets, while the RM7800 series operates on 120 VAC, which is standard for North American applications.
How do I troubleshoot a Lockout on the 7800 Series?
Troubleshooting is best performed using the S7800A Keyboard Display Module, which provides first-out annunciation and specific fault codes (e.g., 'Lockout 28: Pilot Flame Fail'). Alternatively, the blink pattern on the LED status lights can indicate the general fault category.
Can I replace an old Honeywell RA890 with a 7800 Series control?
Yes, the 7800 Series is often used to upgrade legacy RA890, R4140, or BC7000 controls. You will need the appropriate relay module (like the RM7895), a Q7800 wiring subbase, a plug-in purge card, and a flame amplifier matching your existing scanner.
All 7800 Series Models
EC78 Relay Modules
RM78 Relay Modules
Amplifiers (R78)
Timers (ST78)
Subbases (Q78)
Other Models
Need Relay Modules?
Contact our team for 7800 Series configuration help and replacement modules.