Need Custom Pricing? Request a Quote!
Request a free quote for bulk orders or repairs—response in 24 hours. Or get tailored advice and a quote for your automation needs.
Get Your Free Quote!
If you run commercial or industrial boilers, chances are you have Honeywell 7800 SERIES flame safeguard controllers somewhere in your plant. Whether you are maintaining a boiler room with aging RM7800 modules or planning an upgrade to the microprocessor-based EC7800 platform, the right controller choice affects uptime, compliance, and your maintenance budget.
This guide covers every Honeywell burner control series we carry, explains how they differ, and helps you match the correct replacement to your existing system.
Understanding Honeywell's Burner Control Families
Honeywell organizes its flame safeguard controls into several product families. Each family shares a common wiring subbase and programming philosophy but differs in features, timing flexibility, and communication capability.
| Series | Generation | Key Feature | Typical Application |
|---|---|---|---|
| RM7800 | Relay-based | Proven reliability, simple LED diagnostics | Standard commercial boilers, process heaters |
| RM7840 | Relay-based (enhanced) | Programmable purge & ignition timing | Applications requiring custom timing sequences |
| RM7850 | Relay-based | Intermittent pilot with interrupted ignition | Gas-fired appliances, smaller commercial units |
| RM7890 | Relay-based | On/off primary control with economical design | Residential-to-light-commercial crossover |
| RM7895 | Relay-based | Microprocessor timing with relay outputs | Multi-burner installations, demanding timing |
| EC7800 Series (EC7850, EC7890) | Microprocessor | Digital display, S7800 keyboard, self-diagnostics | New installations, upgrades from RM7800 |
RM7800 series: the one you probably already have
The RM7800 is the most widely installed Honeywell flame safeguard controller in North America. Relay-based, predictable startup sequences, and troubleshooting through front-panel LEDs that any boiler tech can read.
Key RM7800 Models We Carry
| Part Number | Description | Purge Timing | Fuel Type |
|---|---|---|---|
| RM7800E1010 | LF&HF Programmer, 120 VAC | Measured purge | Gas/Oil |
| RM7800L1012 | LF&HF Programmer, 120 VAC | Standard purge | Gas/Oil |
| RM7800L1079 | LF&HF Programmer, 120 VAC | Standard purge | Gas/Oil |
| RM7800L1087 | LF&HF Programmer, 120 VAC | Standard purge | Gas/Oil |
All RM7800 modules mount on the same Q7800 wiring subbase, making field replacement straightforward — pull the old module, insert the new one, and verify flame signal strength.
Related guides: RM7800 Series Troubleshooting: LED Sequences, Lockout Codes & Common Failures · RM7800 Wiring Guide: Q7800 Subbase Terminal Connections
RM7840 series: when you need to adjust the timing
If your burner needs non-standard purge durations or ignition timing, the RM7840 has what the RM7800 lacks: programmable flexibility. It uses DIP switches or plug-in timing cards to adjust purge, ignition trial, and post-purge intervals.
Available RM7840 Models
| Part Number | Description | Key Differentiator |
|---|---|---|
| RM7840L1018 | Programmable LF&HF Controller | Adjustable purge & pilot timing |
| RM7840L1075 | Programmable LF&HF Controller | Extended purge capability |
Related guide: RM7800 vs RM7840: Which Flame Safeguard Controller Do You Need?
RM7890 & RM7895: Specialized Controls
RM7890 — On/Off Primary Control
The RM7890 is a cost-effective on/off burner control designed for simpler heating applications. It provides basic flame supervision without the full programming flexibility of the RM7800 or RM7840.
| Part Number | Description |
|---|---|
| RM7890A1015 | On/Off Primary Control, 120 VAC |
| RM7890A1031 | On/Off Primary Control, 120 VAC |
RM7895 — Microprocessor Timing
The RM7895 sits between the RM7800's relay design and the full EC7800 microprocessor platform. It gives you microprocessor-controlled timing with relay outputs — a good fit for multi-burner installations that need precise, repeatable sequences.
| Part Number | Description |
|---|---|
| RM7895A1014 | Microprocessor Programmer, 120 VAC |
| RM7895B1013 | Microprocessor Programmer, 120 VAC, enhanced diagnostics |
Additional RM Series Models
| Part Number | Series | Description |
|---|---|---|
| RM7850A1019 | RM7850 | Intermittent pilot control with interrupted ignition |
| RM7897A1002 | RM7897 | Automatic programming control for complex sequencing |
| RM7898A1000 | RM7898 | Full-featured burner management controller |
EC7800 series: the microprocessor upgrade
The EC7800 is Honeywell's current-generation burner management platform. It swaps the RM7800's relay logic for microprocessor-based control, adding digital self-diagnostics, an optional S7800A1142 Keyboard Display Module, and safety features that meet current FM and UL requirements.
EC7800 Models Available
| Part Number | Description | Equivalent RM Series |
|---|---|---|
| EC7850A1080 | Microprocessor intermittent pilot control | Replaces RM7850 |
| EC7890B1028 | Microprocessor on/off primary control | Replaces RM7890 |
The EC7800 series mounts on the same Q7800 subbase as the RM7800, which means upgrading does not require rewiring. Swap the module, connect the S7800A keyboard display for configuration, and commission.
Related guides:
- Honeywell Burner Control Part Number Cross-Reference: RM to EC Series
- Upgrading from RM7800 to EC7800: What Changes and What Stays the Same
Flame Amplifiers: Matching the Right Sensor to Your Control
Every 7800 SERIES controller requires a compatible flame amplifier module to detect and verify burner flame. The amplifier type must match your flame detection method — rectification (for gas), ultraviolet (for oil and gas), or infrared.
| Part Number | Detection Type | Compatible Controllers |
|---|---|---|
| R7847A1033 | Rectification | RM7800, RM7840, RM7895 |
| R7847A1074 | Rectification | RM7800, RM7840, RM7895 |
| R7847B1072 | Rectification (dynamic) | RM7800, RM7840, RM7895 |
| R7849A1023 | Ultraviolet (UV) | RM7800, RM7840, EC7800 series |
| R7849B1021 | Ultraviolet Ampli-Check | RM7800, RM7840, EC7800 series |
| R7861A1026 | Flame signal (infrared) | RM7800, RM7840, EC7800 series |
| R7861A1034 | Flame signal (infrared) | RM7800, RM7840, EC7800 series |
Tip: When replacing a flame amplifier, always verify the flame signal strength reading on the controller's display or LED sequence before and after the swap. A weak signal (below 1.25 VDC) on a new amplifier usually indicates a sensor positioning issue, not a defective amplifier.
Accessories
| Part Number | Description | Use With |
|---|---|---|
| S7800A1142 | Keyboard Display Module — view status, configure parameters, read fault history | EC7800 series, RM7895 |
| ST7800A1047 | Purge Timer — 40-second purge card for 7800 SERIES subbases | All 7800 SERIES controllers |
How to Choose the Right Replacement Controller
Selecting the correct Honeywell burner control replacement comes down to four factors:
- Identify your current controller. Pull the existing module from the Q7800 subbase and note the full part number (e.g., RM7800L1012). The suffix determines the specific configuration — voltage, purge timing, and fuel type.
- Decide: like-for-like or upgrade? If your facility is satisfied with the existing control sequence, replace with the same part number. If you need digital diagnostics, data logging, or compliance with updated FM/UL codes, step up to the EC7800 series.
- Verify flame amplifier compatibility. RM7800 rectification amplifiers (R7847 series) work with the RM-to-EC upgrade path, but confirm the amplifier type matches your flame detector.
- Check purge timing requirements. Measured purge, standard purge, and timed purge sequences vary by model. Your boiler insurance carrier or local code authority may dictate minimum purge times.
More industrial automation guides
Honeywell burner controls are often part of larger automation systems. If you are also evaluating PLCs or drives for your facility, these guides may help:
- Siemens S7-1500 Complete Buyer's Guide: CPUs, I/O Modules & Accessories
- Allen-Bradley PLC Buyer's Guide: ControlLogix vs CompactLogix vs Micro800
- PowerFlex VFD Selection Guide: 525 vs 753 vs 755
Frequently Asked Questions
Can I replace an RM7800 with an EC7800 without rewiring?
Yes. The EC7800 series uses the same Q7800 wiring subbase as the RM7800. You remove the old RM module, insert the EC module, and connect the optional S7800A keyboard display for configuration. No field wiring changes are needed.
What is the difference between RM7800 and RM7840?
The RM7800 provides fixed timing sequences, while the RM7840 offers programmable purge, ignition trial, and post-purge intervals. Choose the RM7840 when your burner requires non-standard timing that the RM7800's fixed sequence cannot accommodate. See our detailed comparison guide for a full breakdown.
Which flame amplifier do I need for my 7800 SERIES controller?
It depends on your flame detection method. For gas burners using a flame rod, choose a rectification amplifier (R7847 series). For oil or combination burners using a UV scanner, choose an ultraviolet amplifier (R7849 series). For infrared detection, use the R7861 series. The amplifier must match both your sensor type and your controller model.
How do I read the LED fault codes on an RM7800?
The RM7800 uses a sequence of front-panel LEDs to indicate its current state and any fault conditions. A steady red LED typically indicates a safety lockout requiring manual reset. Blinking patterns correspond to specific fault codes — refer to our RM7800 Troubleshooting Guide for the complete LED sequence chart and resolution steps.
Are RM7800 controllers still available or discontinued?
Honeywell still manufactures many RM7800 variants, and we carry the most common part numbers in stock including the RM7800E1010, RM7800L1012, RM7800L1079, and RM7800L1087. However, Honeywell is actively promoting the EC7800 series as the long-term replacement platform, so planning a migration path is advisable for facilities looking 5-10 years ahead.
Browse Our Honeywell Burner Control Inventory
We stock RM7800, RM7840, RM7890, RM7895, and EC7800 series controllers along with matching flame amplifiers, display modules, and timing accessories. All units ship new with manufacturer warranty.
Browse all Honeywell products or request a quote for volume pricing and lead time on specific part numbers.