1. Introduction
This manual provides essential information for the safe and efficient installation, operation, and maintenance of your De Dietrich ZENA Plus MSL 31 MI FF wall-mounted gas boiler. The ZENA Plus MSL 31 MI FF is a reliable and efficient double-circuit boiler designed for both heating and domestic hot water supply, offering an annual capacity of up to 92%. It features a robust brass hydraulic unit and precise temperature control for optimal comfort.
2. Safety Information
Please read all safety instructions carefully before installation, operation, or maintenance. Failure to follow these instructions could result in property damage, personal injury, or death.
- Installation and servicing must be performed by a qualified and authorized technician in accordance with local codes and regulations.
- Do not store flammable materials near the boiler.
- Ensure adequate ventilation around the boiler.
- Never attempt to repair or modify the boiler yourself. Contact a qualified service technician.
- In case of a gas leak, immediately shut off the gas supply, open windows, and evacuate the premises. Do not operate electrical switches or phones. Contact your gas supplier and a qualified technician.
- Regularly check the boiler's pressure gauge. If the pressure is too low or too high, consult the troubleshooting section or contact a technician.
3. Package Contents
Upon unpacking, verify that all components are present and undamaged:
- De Dietrich ZENA Plus MSL 31 MI FF Gas Boiler unit
- Wall mounting plate
- Installation template
- User Manual (this document)
- Note: Accessories for hydraulic connection and a propane conversion kit (if needed) are ordered separately.
4. Setup and Installation
The De Dietrich ZENA Plus MSL 31 MI FF boiler comes fully assembled for ease of installation. Installation must be carried out by a qualified professional.
4.1 Site Selection
- Choose a location that allows for proper ventilation and access for maintenance.
- Ensure the wall is structurally sound to support the boiler's weight.
- The boiler is designed for connection to a horizontal/vertical coaxial chimney with forced discharge of combustion products or to separate pipelines for air intake and removal of combustion products.
4.2 Mounting the Boiler
- Use the provided wall mounting plate and installation template to accurately mark drilling points.
- Securely attach the mounting plate to the wall.
- Carefully lift and hang the boiler onto the mounting plate.
4.3 Gas and Water Connections
- Connect the boiler to the gas supply line. The boiler is designed to run on natural gas or propane (a propane conversion kit is ordered as additional equipment if using propane).
- Connect the heating circuit pipes (flow and return).
- Connect the domestic hot water pipes (cold water inlet and hot water outlet).
- Ensure all connections are sealed and leak-free.
- Fill the heating system with water and bleed air from the system.
4.4 Electrical Connection
- Connect the boiler to a dedicated electrical circuit as per local regulations.
- If desired, connect room thermostats and an outdoor temperature sensor for enhanced efficiency and control.
4.5 Flue Gas System Connection
- Connect the flue gas system according to the boiler type (closed combustion chamber) and local regulations. This model is for connection to a horizontal/vertical coaxial chimney or separate pipelines.
5. Operating Instructions
The boiler features a functional electronic control panel with a digital display and backlight for easy operation.
5.1 Control Panel Overview
The control panel typically includes:
- Digital Display: Shows current temperature, operating status, and error codes.
- Function Keys: Buttons for adjusting settings, switching modes (heating/hot water), and accessing menus.
- Mechanical Pressure Gauge: Indicates the system water pressure.
5.2 Starting the Boiler
- Ensure the gas supply valve is open.
- Ensure the water supply valves to the boiler are open and the system pressure is within the recommended range (check the mechanical pressure gauge).
- Turn on the electrical power to the boiler.
- The boiler will initiate an electronic ignition sequence. The ionization flame control will monitor the flame presence.
- Select the desired operating mode (heating, hot water, or both) using the control panel keys.
- Set the desired temperature for heating and/or hot water. The boiler offers full temperature control with degree accuracy.
5.3 Shutting Down the Boiler
- For temporary shutdown, switch off the boiler via the control panel.
- For complete shutdown (e.g., for extended periods or maintenance), turn off the electrical power, close the gas supply valve, and close the water supply valves.
5.4 Hot Water Comfort Function
The boiler includes a special function to maintain the temperature in the primary circuit of the plate heat exchanger, ensuring a high level of comfort for domestic hot water supply.
6. Maintenance
Regular maintenance is crucial for the boiler's efficiency, safety, and longevity. All maintenance should be performed by a qualified technician.
6.1 Annual Servicing
- It is recommended to have your boiler serviced annually by a qualified technician.
- Servicing typically includes checking the burner, heat exchanger, gas connections, safety devices, and overall system performance.
6.2 User Checks
- Pressure Check: Periodically check the system pressure on the mechanical pressure gauge. It should typically be between 1.0 and 1.5 bar when the system is cold.
- Visual Inspection: Look for any signs of leaks, corrosion, or unusual noises.
- Ventilation: Ensure that air vents are not blocked.
6.3 Cleaning
- Clean the exterior of the boiler with a soft, damp cloth. Do not use abrasive cleaners or solvents.
7. Troubleshooting
The electronic control panel has a built-in diagnostic system with error codes. Refer to the display for specific codes. Below are some common issues and general solutions.
| Problem | Possible Cause | Solution |
|---|---|---|
| Boiler not firing / No heat | No gas supply, low system pressure, electrical fault, thermostat setting too low. | Check gas valve. Check pressure gauge and repressurize if needed. Check power supply. Adjust thermostat. If problem persists, contact technician. |
| No hot water | Boiler in heating-only mode, flow sensor fault, hot water temperature set too low. | Check boiler mode. Adjust hot water temperature. If problem persists, contact technician. |
| Low system pressure | Leak in the system, expansion vessel fault. | Locate and fix leaks. Repressurize the system (refer to installation guide or contact technician). If frequent, contact technician. |
| Error code displayed | Specific fault detected by the boiler's diagnostic system. | Note the error code and consult the boiler's detailed error code list (usually in the full technical manual) or contact a qualified technician, providing the error code. |
| Unusual noises | Air in the system, pump issue, limescale buildup. | Bleed air from radiators. If noises persist or are severe, contact a qualified technician. |
For any issues not resolved by these steps, or for persistent problems, please contact a qualified De Dietrich service technician.
8. Specifications
| Feature | Detail |
|---|---|
| Model | ZENA Plus MSL 31 MI FF |
| Type | Wall-mounted, Double-circuit Gas Boiler |
| Combustion Chamber | Closed |
| Fuel Type | Natural Gas or Propane (with conversion kit) |
| Annual Efficiency | Up to 92% |
| Primary Heat Exchanger | Copper with aluminum-silicon paint |
| DHW Heat Exchanger | Stainless Steel Plate |
| Expansion Tank Volume | 10 liters |
| Hydraulic Unit | Brass, includes 3-speed pump, automatic air vent, automatic bypass, heating/DHW switch valve, water pressure switch, drain tap, 3 bar safety valve, flow meter. |
| Control Panel | Electronic with digital display and backlight, diagnostic system. |
| Ignition | Electronic |
| Flame Control | Ionization |
| Flue Gas System | For connection to horizontal/vertical coaxial chimney or separate pipelines. |
| Package Dimensions (L x W x H) | 40 cm x 70 cm x 30 cm |
| Package Weight | 430.0 kg |
9. User Tips
Based on general user experiences with similar products:
- Consider installing an outdoor temperature sensor for optimal energy efficiency, allowing the boiler to adjust heating output based on external conditions.
- Utilize programmable room thermostats to set heating schedules that match your lifestyle, further reducing energy consumption.
- Regularly check the system pressure, especially after bleeding radiators, to ensure it remains within the recommended operating range.
Note: No specific user reviews or Q&A content were provided for this product to generate more tailored tips.
10. Warranty and Support
For warranty information, technical support, or to schedule service, please contact your authorized De Dietrich dealer or service center. Keep your purchase receipt and boiler model/serial number handy when contacting support.
Always ensure that any servicing or repairs are carried out by qualified and certified technicians to maintain warranty validity and ensure safe operation.