Introduction
This document provides detailed instructions for the installation of the Buderus Logatherm WLW MB AR air-to-water heat pump. It covers all essential aspects from product description and safety precautions to installation, hydraulic and electrical connections, maintenance, and technical data.
1. Symbol Explanation and Safety Instructions
1.1 Symbol Explanation
Signal words like DANGER, WARNING, CAUTION, and NOTICE are used to indicate the severity of potential hazards. Specific symbols are used to denote actions, cross-references, and list items.
1.2 General Safety Instructions
This installation guide is intended for plumbers, heating installers, and electricians. It is crucial to read all installation instructions for the heat pump, controller, etc., before installation. National and regional regulations, technical standards, and guidelines must be adhered to. All work performed must be documented.
1.2.1 Intended Use
The heat pump is designed for use in closed heating systems in residential buildings. Any other use is considered improper and Buderus is not liable for damages resulting from such use.
1.2.2 Installation, Commissioning, and Maintenance
Installation, commissioning, and maintenance must only be carried out by authorized personnel. Buderus is not liable for damages caused by modifications not described in this manual. Only use original spare parts.
1.2.3 Special Qualifications for Refrigerant R290
Work on the refrigerant circuit and systems with flammable refrigerants requires special training. Adhere to applicable laws and regulations.
1.2.4 Flammable Gases! Fire and Explosion Hazard
The product contains the flammable refrigerant R290. In case of leakage, flammable gas can form upon contact with air, posing a fire and explosion hazard. Use a gas detector when working on the refrigerant circuit and ensure no ignition sources are present.
1.2.5 Electrical Work
Electrical work must be performed by a qualified electrician. Ensure the unit is de-energized before starting any electrical work.
1.2.6 Connection to the Power Supply
The unit's power supply must be safely interruptible. Install a main-pole safety switch that completely disconnects the unit from the power supply. This switch must be of surge protection category III.
2. Product Description
2.1 Scope of Delivery
The delivery includes the heat pump, condensate drain connector, transport straps, base brackets, cable ties for securing cables in the connection box during installation, and documentation. A drilling template is printed on the accessory box.
2.2 Declaration of Conformity
This product complies with all applicable EU directives. The full text of the Declaration of Conformity is available online at www.buderus.de.
2.3 Information on the Heat Pump
The Logatherm WLW MB AR series are heat pumps designed for connection to the Logatherm WLW 176i/186i T180, Logatherm WLW 176i/186i E, or Logatherm WLW 176i/186i TP70 indoor units.
2.4 Available Accessories
Accessories include a mounting kit with insulation and pipe cladding, an accessory heating cable for longer condensate drain pipes, and wall brackets for wall mounting. A base is available for units requiring greater floor clearance.
2.5 Product Overview
The heat pump is equipped with a transport lock (screw) to prevent transport damage. This must be removed before installation.
2.6 Regulations
This is an original manual. Translations must not be made without the manufacturer's consent. Adhere to local regulations, utility company requirements, national building codes, and standards such as EN 50160, EN 12828, EN 1717, EN 378, and EN 60335-2-40.
2.7 Dimensions
Detailed dimensions of the heat pump and required clearances are provided in diagrams.
2.8 Protection Zones
Due to the flammable refrigerant R290, specific protection zones must be maintained around the product to prevent the accumulation of refrigerant in case of a leak. These zones must be kept clear of building openings and ignition sources.
3. Installation Preparation
3.1 Transport and Storage
DANGER: Fire and life hazard! The product contains flammable refrigerant R290. Store and transport the unit in a well-ventilated area away from ignition sources. Transport and store the unit upright, with a maximum tilt of 45°. Storage temperature range is -30 °C to +60 °C. Avoid mechanical damage.
3.2 Installation Location
Install the heat pump outdoors on a level and stable surface. Ensure accessibility for maintenance. Consider the sound pressure level to avoid disturbing neighbors. Do not install in corners that are enclosed on three sides by walls, as this can increase noise levels and lead to evaporator soiling. Avoid locations where large amounts of water or snow can slide off the roof. If necessary, install a protective roof at least 1000 mm above the unit. Protect the air intake from walls or similar structures. Do not expose the front of the heat pump to wind.
3.3 Installation Clearances
Recommended clearances between the heat pump and surrounding objects are provided in diagrams to ensure proper airflow and performance. Deviations may lead to increased noise levels or reduced heat output.
3.4 Water Quality
The quality of the filling and make-up water is crucial for efficiency, safety, and lifespan. Use only drinking water. Do not use well or ground water. Determine water hardness before filling. Flush the heating system before filling. If magnetite is present, corrosion protection measures are required. For the German market, water must comply with the German Drinking Water Ordinance (TrinkwV). For other markets, adhere to the specified limit values. Water treatment may be necessary for systems with a water content exceeding 40 l/kW. Desalination to a conductivity of ≤ 10 µS/cm is recommended.
3.5 Minimum Volume and Design of the Heating System
The heating system must have sufficient energy storage capacity to prevent excessive start/stop cycles and ensure proper operation. Check the conditions of the heating system in the installation manual for the respective indoor unit.
4. Installation
4.1 Checklist
A general checklist for the installation process is provided, including mounting the heat pump, removing the transport lock, connecting the condensate drain, mounting pipes and insulation, connecting the heat pump to the indoor unit, connecting the CAN-BUS cable, and connecting the power supply.
4.2 Mounting the Heat Pump
CAUTION: Risk of pinching or injury! The heat pump can tip over if not properly secured. Anchor the heat pump to the floor. Ensure the inclination of the heat pump does not exceed 1% horizontally and vertically. Use the provided drilling template for mounting screws. Adjust the height using the foot screws to ensure the unit is level. Secure the heat pump to the floor with appropriate screws.
4.3 Mounting on a Base
The heat pump can be mounted on a base if greater ground clearance is required. Refer to the accessory manual for base mounting instructions.
4.4 Mounting with a Mounting Kit
The mounting kit can be used for wall mounting or floor mounting. Refer to the accessory manual for details.
4.5 Mounting the Wall-Mounted Outdoor Unit
CAUTION: Risk of injury! Use appropriate fasteners for the wall material. Ensure the wall can support the entire load. If the outdoor unit is accessible via a ladder, do not install it higher than 3 m above the ground.
5. Hydraulic Connection
5.1 General Pipe Connections
NOTICE: Damage to the system due to residues in the pipes! Avoid solid particles, metal/plastic shavings, hemp, or thread seal tape residues from entering pumps, valves, and heat exchangers. Prevent foreign objects from entering the pipe system. Do not lay pipe components directly on the floor. Ensure no shavings remain in the pipes after deburring. Flush the pipe system before connecting the heat pump and indoor unit. For outdoor pipes, use at least 19 mm thick insulation. Install drain valves to allow water to be drained in case of prolonged downtime and frost. Use UV and moisture-resistant insulation. All heat-carrying pipes must be insulated according to applicable standards. For cooling operation, all connections and pipes must be insulated to prevent condensation. Insulate wall penetrations. Refer to the indoor unit installation manual for pipe dimensions. Do not glue heat transfer pipes to minimize pressure loss. Use PEX pipes for all connections between the heat pump and the indoor unit. Use PEX or AluPEX pipes from the same manufacturer to avoid leaks. Pre-insulated AluPEX pipes are recommended for easier installation and to prevent gaps in insulation. PEX or AluPEX pipes also dampen vibrations and prevent noise transmission to the heating system.
5.1.1 Alternative Material Requirements
If a material other than PEX is used, a particle filter must be installed on the return line directly at the heat exchanger. The particle filter must be insulated like other connections. Protect the heat pump connection from vibrations with a suitable outdoor hose and insulate it.
5.2 Condensate Drainage
NOTICE: Damage due to frost! If condensate freezes and cannot be drained, evaporator damage may occur. Always install a pipe heating cable if ice formation in the condensate line is possible. The condensate must be drained frost-free with sufficient slope. The condensate can be discharged into a gravel bed or a drainage channel. The drain pipe diameter must be larger than the drain nozzle. The drain pipe and drain nozzle must not be connected directly.
5.3 Foundation Plan without Base
Detailed foundation plans (Alternative 1 and Alternative 2) are provided with dimensions for proper installation.
5.4 Connecting the Heat Pump to the Indoor Unit
NOTICE: Damage due to excessive tightening torque! Overtightening connections can damage the heat exchanger. Use a maximum tightening torque of 150 Nm. Short connections in outdoor areas reduce heat loss. Pre-insulated pipes are recommended. Connect the flow pipe to the heat transfer outlet and the return pipe to the heat transfer inlet. Tighten connections with a torque of 120 Nm, using a second wrench to hold the fitting. If a connection is not leak-proof, the torque can be increased to 150 Nm. If the connection remains leaky, it may indicate a damaged seal or pipe.
6. Side Cover and Transport Lock
6.1 Removing the Side Cover
Instructions are provided for removing the side cover.
6.2 Removing the Transport Lock
The heat pump is equipped with a screw as a transport lock to prevent damage during transport. This screw must be removed before installation.
7. Electrical Connection
7.1 CAN-BUS
NOTICE: System damage due to mixed-up 24 VDC and CAN-BUS connections! Communication circuits are not designed for a constant 24 VDC voltage. Check that cables are connected to the correctly labeled terminals. NOTICE: Malfunction due to reversed connections! If the HIGH (H) and LOW (L) terminals are reversed, communication between the heat pump and indoor unit will not function. Ensure CAN-BUS cables are connected correctly at both ends.
The heat pump and indoor unit are connected via a CAN-BUS communication line (24 VDC, Protection Class III (SELV)). Use LIYCY (TP) 2 x 2 x 0.75 cable or equivalent for extension cables. Maximum cable length is 30 m. The connection uses four wires, which also supply the 24 VDC power. The 24 VDC and CAN-BUS terminals are marked on the module. The CAN-BUS cable consists of two twisted wire pairs. Vcc and GND form one pair, H and L form the second pair. Maximum sheathing length for all cables is 120 mm. Maximum stripping length is 8-10 mm.
7.2 Connecting the Heat Pump
Ensure proper strain relief for electrical cables. Secure cables with cable ties. Route connection cables through cable glands. Remove the rubber grommet for the respective cable from the outdoor unit. Route the CAN-BUS connection cable through the left cable gland (1). Route the power connection cable through the right cable gland (2). Pierce the rubber grommet and slide it onto the cable. Insert the cable into the cable gland until the section on the other side is sufficiently long. Insert the rubber grommet back into the opening of the outdoor unit. Strip the cable according to Figure 37. Connect the cable according to Figure 36. Secure the cable ties. Reattach the side cover.
7.3 Connecting the Accessory Heating Cable
Ensure proper strain relief for electrical cables. Use cable ties on the plate for cabling by the installer. Remove the side cover. Route the heating cable according to the accessory instructions for the drain pipe. Connect the cable according to Figure 38. Tighten cable ties. Reattach the side cover.
8. Maintenance
8.1 Cleaning the Condensate Tray
Use a brush and cloth with a mild cleaning agent. Do not use a water hose. Remove the left side cover. Unscrew the screw securing the EPP segments. Remove the two EPP segments. Clean the drip tray. Re-screw the EPP segments and reattach the side cover.
8.1.1 Cleaning the Condensate Tray
DANGER: Fire and life hazard! The product contains flammable refrigerant R290. Work on the refrigerant circuit must only be performed by personnel specially trained for R290. Use personal protective equipment. Keep a fire extinguisher readily available. Ensure tools and operating materials are in perfect condition and approved for R290. DANGER: Electric shock hazard! The heat pump contains live components. The heat pump capacitor must be discharged after interrupting the power supply. Disconnect the unit from the mains. Wait at least five minutes after disconnecting power before working on the electrical system. NOTICE: Malfunction due to damage! Electronic expansion valves are very sensitive to shock. Protect the expansion valve from impacts and shocks in all cases.
8.1.2 Maintenance Tasks
Check for heat-induced deformation of the insulation material (EPP). Remove as much insulation as possible before soldering. Protect insulation material with heat-resistant materials or damp cloths during soldering. Use only original spare parts. Replace removed seals and O-rings with new ones. During inspection, perform the following tasks: Check activated alarms and the alarm log. Perform a function check. Check power cables for mechanical damage and replace damaged cables. Evacuate refrigerant only in special situations, performed by qualified personnel familiar with R290 risks. Use personal protective equipment and have a fire extinguisher ready. Use only tools and equipment approved for R290. Refer to safety instructions for handling flammable refrigerants. Dispose of refrigerant according to regulations for recycling.
9. Environmental Protection and Disposal
Environmental protection is a core principle. Buderus adheres to all environmental laws and regulations. Packaging materials are environmentally compatible and recyclable. Used equipment can be recycled. Electrical and electronic equipment must not be disposed of with other waste but must be taken to designated collection points for treatment, collection, recycling, and disposal. This complies with regulations like the EU WEEE Directive. Responsible recycling minimizes environmental damage and health risks and conserves natural resources. For more information, contact local authorities or your retailer.
10. Technical Information and Protocols
10.1 Technical Data - Heat Pump
Detailed technical data for the MB-4 AR, MB-5 AR, and MB-7 AR models are provided, including performance data at various temperatures, SCOP values, cooling capacity, EER values, electrical data, and noise emission levels.
10.2 Operating Range for Heat Pump without Auxiliary Heater
The heat pump switches off at approximately -20 °C (heating) or +45 °C (cooling). Auxiliary heating or an external heat source takes over. The heat pump restarts when the outside temperature rises above approximately -17 °C (heating) or +42 °C (cooling).
10.3 Refrigerant Circuit
A diagram of the refrigerant circuit is provided, illustrating the flow of refrigerant during heating, defrosting, and cooling modes. Components are labeled with their respective codes.
10.4 Circuit Diagrams
Detailed circuit diagrams for the frequency converter and the XCU-SRH (XCU-HP) control unit are included.
10.4.3 Measured Values for Temperature Sensors
Tables provide the measured resistance values for various temperature sensors at different temperatures.
