Baxi CPA-BT Series - User Manual

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

The document describes the BAXI CPA-BT series of low-temperature boilers, which are designed for heating applications. These boilers are characterized by their robust construction and efficient operation, suitable for both residential and commercial use.

Function Description

The CPA-BT boilers are low-temperature heating units designed to provide hot water for central heating systems. They operate at lower temperatures compared to conventional boilers, which contributes to higher efficiency and reduced energy consumption. The boilers are compatible with various types of burners, including those for gas (natural gas and propane) and oil, allowing for flexibility in fuel choice. They can be configured for single-stage, two-stage, or modulating burner operation, depending on the specific model and control panel used.

The system incorporates a control panel that manages the boiler's operation, including burner activation, pump control, and safety functions. Different control panel options are available: a basic control panel for single or two-stage operation, and a digital KSF/QSF control panel for more advanced control, including modulating operation. These panels allow for precise temperature regulation and system monitoring.

The boiler's design emphasizes ease of installation and maintenance. It features a robust steel body, a large combustion chamber, and a system for efficient heat exchange. The design also includes provisions for connecting various external components such as pumps, expansion vessels, and safety valves.

Important Technical Specifications

The CPA-BT series includes a wide range of models, from the CPA 55-BT to the CPA 1740-BT, with varying nominal power outputs.

Power Output:

Nominal useful power ranges from 55 kW (CPA 55-BT) to 1740 kW (CPA 1740-BT).
Useful heat output at 100% of charge and 70°C average temperature ranges from 55 kW to 1740 kW.
Useful heat output at 30% of charge and 40°C average temperature ranges from 16.6 kW to 524.2 kW.

Efficiency:

Efficiency at 100% load and 70°C average temperature is consistently high, around 91.0% to 93.5% across models.
Efficiency at 30% load and 40°C average temperature is even higher, ranging from 91.4% to 93.9%.
ErP parameters indicate useful efficiency at rated heat output and low temperature regime (1) between 85.8% and 96.8%, and useful efficiency at rated heat output and low temperature regime (2) between 82.6% and 83.8%.

Water Content:

Water content (L) varies significantly by model, from 115 L (CPA 55-BT) to 1739 L (CPA 1740-BT).

Maximum Working Pressure:

All models have a maximum working pressure of 5 bar.

Set Temperature Range:

The set temperature range for all models is 50-90°C.

Fuel Consumption:

Fuel consumption varies based on the type of fuel (natural gas, propane, or oil) and the boiler's power output. For example, the CPA 55-BT consumes 5.09 Nm³/h of natural gas, while the CPA 1740-BT consumes 158.60 Nm³/h.

Combustion Chamber:

Combustion chamber volume (m³) ranges from 0.097 m³ (CPA 55-BT) to 1.403 m³ (CPA 1740-BT).

Pressure Drop in Water Circuit:

Pressure drop at ΔT=10°C ranges from 18.0 mbar to 121.5 mbar.
Pressure drop at ΔT=20°C ranges from 4.5 mbar to 30.3 mbar.

Dimensions:

The boilers come in various sizes. For instance, the CPA 55-BT has dimensions of 870mm (A), 945mm (B), 1114mm (C), 465mm (D), 665mm (E), 175mm (F), 279mm (G), 240mm (H), 105mm (I), 764mm (J), 1014mm (K), 92mm (L), 185mm (M), and 17mm (N). Larger models like the CPA 1740-BT have significantly larger dimensions.

Flue Gas Connections:

Flue gas connection diameters vary by model, from DN 65 (CPA 55-BT) to DN 200 (CPA 1740-BT).

Electrical Supply:

Monophasic 230 V (+10%-15%) - 50 Hz.
Protection grade: IP20.

Usage Features

Versatility: The CPA-BT boilers are designed for a wide range of applications, from small residential systems to larger commercial or industrial installations. Their compatibility with different fuel types (gas and oil) and burner configurations (single-stage, two-stage, modulating) makes them highly adaptable.

Control Systems:

Basic Control Panel (1 or 2 stages): This panel provides essential control over the boiler's operation, including burner activation and temperature settings. It is suitable for simpler heating systems.
Digital KSF/QSF Control Panel (1, 2 stages, and modulating): This advanced panel offers more precise control, allowing for modulating burner operation, which optimizes fuel consumption and maintains a more stable temperature. It also includes enhanced diagnostic and safety features.

Temperature Management: The boilers are designed to operate at low temperatures, which is beneficial for systems that incorporate radiant floor heating or other low-temperature emitters. The ability to set a temperature range of 50-90°C provides flexibility for different heating needs.

Safety Features: The manual outlines several safety checks and components, including:

Door safety switch to prevent operation when the door is open.
Pressure switches for air and gas to ensure proper combustion conditions.
Safety valves to prevent overpressure in the system.
Thermostats for high temperature limits.

Installation Flexibility: The boilers can be installed in various configurations. The manual provides detailed instructions for connecting the boiler to the heating system, including flow and return pipes, expansion vessels, and safety devices. It also covers the installation of the burner and the electrical connections to the control panel.

Maintenance Features

Ease of Access: The design of the CPA-BT boilers allows for easy access to internal components for maintenance and cleaning. The combustion chamber door can be opened to facilitate inspection and cleaning of the heat exchange surfaces.

Cleaning Procedures:

Combustion Chamber and Flue Gas Passages: Regular cleaning of the combustion chamber and flue gas passages is crucial to maintain efficiency and prevent soot buildup. The manual recommends using a brush and vacuum cleaner for this purpose.
Burner Maintenance: The burner should be periodically inspected and cleaned according to the burner manufacturer's instructions. This includes checking the nozzle, electrodes, and fan.

Component Inspection:

Seals and Gaskets: All seals and gaskets, particularly those on the combustion chamber door and flue gas connections, should be inspected regularly for wear and tear and replaced if necessary to ensure gas tightness.
Safety Devices: Safety valves, pressure switches, and thermostats should be checked periodically to ensure they are functioning correctly.
Electrical Connections: All electrical connections should be inspected for tightness and signs of corrosion.

Condensation Prevention: The manual emphasizes the importance of preventing condensation in the boiler, especially in low-temperature systems. It provides guidelines for maintaining minimum return water temperatures to avoid corrosion and extend the boiler's lifespan. For oil burners, the minimum return temperature should be 35°C, and for gas burners, 30°C.

Regular Servicing: To ensure optimal performance and longevity, the boiler should undergo regular maintenance checks by qualified personnel. The manual recommends a maintenance plan that includes periodic inspections and cleaning of key components.

Troubleshooting: The manual provides a section on troubleshooting common issues, such as burner lockout, pump malfunctions, and temperature control problems, to assist installers and technicians in diagnosing and resolving issues.