PAW-TD23B6E5 Installation and Operation Manual

Product Overview

The OSO PAW-TD23B6E5 is a high-grade stainless steel tank-in-tank unit designed to supply domestic hot water and heating to radiators or underfloor heating systems. It features high performance, very low heat losses due to 50 mm of 4th generation PUR insulation, a 230L domestic hot water tank with a large heating coil, and a 60L buffer tank to optimize heat pump operation. This technology reduces heat losses, increases energy efficiency, provides greater comfort, and minimizes the system's footprint.

Safety Information

Read all safety instructions carefully before installation, maintenance, or adjustment. Failure to follow instructions may result in personal injury or material damage. Keep this manual and other relevant documents accessible.

Symbols Used:

• ⚠️ WARNING: Could cause serious injury or death.
• ⚠️ CAUTION: Could cause minor or moderate injury or damage to property.
• ? DO NOT: Prohibited actions.
• ℹ️ Information: Important notes or guidance.

General Safety Instructions:

• Only trained and qualified technicians should install, move, modify, or repair this product.
• The product must not be stored outdoors before installation.
• Always wear gloves during installation or repair to avoid hot or cold burns from pipes.

User Safety Instructions:

• ⚠️ WARNING: The overflow from the Temperature & Pressure relief valve must NOT be sealed or plugged. The product must NOT be covered. Do NOT place foreign objects near or on the product. The product must NOT be modified. Children must NOT play with the product or go near it without supervision. The product should be filled with water before power is switched on. Maintenance/settings should only be carried out by persons over 18 years of age with sufficient understanding.
• ⚠️ CAUTION: The product must not be exposed to frost, over-pressure, over-voltage, or chlorine treatment. Maintenance/settings should not be carried out by persons with diminished physical or mental capacity unless instructed by a responsible person.

Installer Safety Instructions:

• ⚠️ WARNING: Overflow from the Temperature & Pressure relief valve must NOT be sealed or plugged. Any overflow pipe must be installed with a continuous fall to the drain/gully. Follow the electrical wiring diagram. No optional wiring is allowed. All electrical work must be performed by an authorized installer. The mains cable should withstand 90°C and have a strain reliever. The product must be filled with water before power is switched on. Follow relevant regulations and standards. For buffer tanks, a safety valve with a rated pressure of max. 0.3 MPa (3 bar) is obligatory to prevent pressure elevation. Annual control of the safety valve is recommended.
• ⚠️ CAUTION: The product should be placed in a room with a drain. It should be properly aligned vertically and horizontally on a suitable floor surface. A service clearance of 120 cm in front and 50 cm on top is required.

Product Description

Product Identification:

Identification details are on the product's type plate.

Intended Use:

To supply domestic hot water in combination with a central heating and cooling system, connected to an external heat pump.

CE Marking:

The product complies with relevant EU directives: Low voltage (LVD 2014/35/EU), Electromagnetic compatibility (EMC 2014/30/EU), and Pressurised equipment (PED 2014/68/EU). Any safety valves used must also be CE-marked and comply with PED 2014/68/EU.

Technical Data:

ErP Data - Technical Data Sheet:

Heat loss tested according to standard: EN 12897:2016

Installation Instructions

Products Covered:

80341990 PAW-TD23B6E5

Included in Delivery:

• 1x Air vent valve for DHW tank
• 1x Temperature and pressure valve (T&P)
• 1x Installation manual (this document)
• 1x DHW tank, 230L, max pressure 10.0 bar
• 1x Electronic box
• 1x 3-way valve
• 1x Terminal block
• 1x Circulation pump
• 1x Drain valve for DHW tank
• 1x Air vent valve for buffer tank
• 1x Buffer tank, 60L, max pressure 3.0 bar
• 1x Drain valve for buffer tank
• 4x Adjustable feet

Product Dimensions:

All dimensions in mm. Tolerance +/- 5 mm (not dimension A).

Diagram: A visual representation of the unit shows dimensions A through F, with connections and components labeled.

Important Notice Before Installation:

Ensure the chosen heat pump is compatible with the existing heating system and power equipment, as well as the nominal water flow, lift height, and system size. Use only clean water. Poor water quality can damage the tank and cause corrosion or clogging. Water quality must not exceed:

• Chloride content: < 100 mg/l
• Total Dissolved Solids: < 200 mg/l
• pH level: > 6.0 / < 9.5

If water quality exceeds these parameters, a sacrificial anode may be installed in the DHW tank's G3/4" connection. The anode must be installed by an authorized installer before filling the system. With an anode installed, water quality must not exceed:

• Chloride content: < 250 mg/l
• Total Dissolved Solids: < 500 mg/l
• pH level: > 6.0 / < 9.5

Pipe Connections and Valves:

Diagram: A top-down view of the unit shows labeled pipe connections (a-i) for radiator return/flow, cold water in, DHW out, T&P valve, heat pump circuit return/flow, air vent valve, and drain valves.

• a: Ø22 Radiator circuit return
• b: Ø22 Domestic cold water in
• c: Ø22 Domestic hot water out
• d: 3/4" Temperature and pressure valve (T&P)
• e: Ø22 Radiator circuit flow
• f: Ø22 Heat pump circuit return
• g: 1/8" Air vent valve for heating system
• h: Ø22 Heat pump circuit flow
• i: DN15 Drain valves (DHW tank & buffer tank)

Transport and Unpacking:

The product is heavy and requires at least two people for lifting. Do not transport horizontally to avoid damage. Wear gloves during handling. Be careful not to damage the product or packaging. Drain installed tanks before moving.

? DO NOT use pipe stubs or valves to lift the product.

Requirements for Installation, Location and Positioning:

• Place the product in a room with a drain to prevent water damage.
• Ensure the area is dry, clean, free of vapor, volatile oils, smoke, and gases.
• Place in a dry and frost-free position.
• Ensure the floor surface can support the product's total weight when in operation.
• Install the tank unit as close to the heat pump as possible to minimize coolant volume.
• Maintain a service clearance of 120 cm in front and 50 cm on top.
• Ensure the product is easily accessible for servicing and maintenance.

Pipe Installation:

The DHW tank connects to the mains water supply. The buffer tank connects to the heating system (max 3 bar). Use approved pipes of the correct size and follow relevant standards.

Heating and Domestic Hot Water:

Use connectors that reduce vibration and withstand water temperature and pressure. Pipes must accommodate temperature differences to prevent system noise.

Pipe Connection Dimensions:

Pipe Installation Procedure:

1. Position the unit and level it using adjustable feet.
2. Flush and clean the existing heating system.
3. Connect the domestic water supply. A mixing valve is recommended.
4. Connect the unit's supply and return pipes to the heating system, following tank markings.
5. Connect an escape pipe and tundish from the T&P relief valve to the floor drain.
6. Connect an escape pipe from the radiator safety valve to the floor drain.
7. Verify expansion vessel sizing (approx. 10% of system volume).
8. Check expansion vessel pressure.
9. Fill the DHW tank first, then the buffer tank. Open a hot water tap for ventilation.
10. Set the 3-way valve to "fill mode" and open the air vent.
11. Fill the radiator system and close the manual air vent.
12. Maintain pressure within the recommended range. Restore the 3-way valve to automatic position.
13. Bleed radiators, check system pressure, and add water if needed. Repeat until all air is removed.
14. Check diverting valve operation and radiator heating. Bleed system when warm and check for leaks.
15. Close the automatic air vent after two weeks.

Removing the Front Cover:

1. Unscrew and remove the two screws at the bottom of the front panel.
2. Pull out the lower part of the front panel (100-150mm).
3. Grip the sides of the front panel and lift it straight up.
4. Carefully remove the front panel to avoid damaging connections.

Diagram: Illustrates the process of removing the front cover.

Pipe Connection Layout:

Diagram: Shows the overall system layout including the DHW tank, buffer tank, heat pump (outdoor and indoor units), and radiator circuit, illustrating the flow of water and heat.

Fitting Instructions:

• ⚠️ WARNING: The product must be filled with water before power is switched on. Overflow pipes must be installed uninterruptable and frost-free with a continuous fall to the drain/gully.
• ⚠️ CAUTION: Place the product in a room with a drain. Ensure the floor surface is suitable for the product's weight. Maintain service clearance of 120 cm in front and 50 cm on top.

Installation Recommendation:

Allow floor clearance for venting. Screw feet out a minimum of 15 mm from the bottom.

Electrical Installation

Use fixed electric fittings installed by an authorized electrician, following relevant standards and regulations.

Wiring:

Connect hydrobox wires to the electronic box as per section 3.6.4. OLP for Booster Heater at HP must be jumpered.

Backup Immersion Heater Thermostat:

The immersion heater is an auxiliary heat source. Power must only be supplied after the unit is filled with water. The unit has one 2.8 kW immersion heater. Use only specified thermostats. Connect live (L), neutral (N), and earth cables as indicated.

The heater requires a minimum 16 amp dedicated supply, a 20 amp double pole isolation switch, and heat-resistant cable (minimum 85°C). The TSR thermostat acts as a safety cut-out at 85°C (±5°C). If it trips, investigate the cause and press the reset button (R).

Replacing the Safety Cut-out Thermostat:

Disconnect power. Loosen screws A and B to remove thermostat. Insert replacement thermostat sensor (D) into tube (E). Push connectors firmly. Refit power cables (L, N) and tighten screws A and B to 2 Nm.

Diagram: Shows the thermostat (TSR COTHERM) and its connection points (A, B, C, D, E) and wiring (L, N).

• ⚠️ WARNING: Constant voltage is present in the electronic box. Disconnect power before any electrical work. The thermostat must not be dismantled/opened, as this compromises function and risks overheating, voiding the warranty.

Fitting Instructions:

• ⚠️ WARNING: Product must be filled with water before power is switched on. Fixed electric fittings must be installed by an authorized electrician. Mains cable should withstand 90°C and have a strain reliever.
• ⚠️ CAUTION: Maintain a service clearance of 120 cm in front and 50 cm on top. Damaged mains cables must be replaced with suitable manufacturer cables.

Electrical Wiring Diagram:

Diagram: A schematic shows the main PCB of the heat pump (Aquarea H and J series) with connections for OLP, sensors, external control, remote controller, boiler contact, extra pump, boiler heater, and terminal block connections (1-12) to the diverting valve, circulation pump, and electric heater.

Maintenance and Draining

Maintenance should be carried out by persons over 18 years of age with sufficient understanding. Contact an authorized installer if in doubt.

Checking the Manometer:

Check twice a year. For radiator systems, pressure should be between 0.5 - 1.2 bar. Fill with water to 1.0 bar if needed.

Checking the Temperature & Pressure Relief Valve:

Test annually by turning the wheel until water streams out. Dripping from the overflow pipe due to temperature variations is normal.

• ⚠️ WARNING: The overflow from the T&P safety valve must NOT be blocked, sealed, or plugged.

Checking the Protective Anode (if installed):

1. Shut down the system and switch off the control fuse.
2. Turn off the cold water supply.
3. Depressurize the buffer tank to less than 0.5 bar.
4. Open a domestic hot water tap to release pressure.
5. Open the drain valve for the DHW tank.
6. Unscrew, pull out, and clean the anode (A).
7. Measure the anode diameter. Replace if less than 10 mm.
8. Refit the anode with 40Nm torque.
9. Close the hot water tap.
10. Open the incoming cold water supply.
11. Repressurize the buffer tank.
12. Restart the system.

⚠️ WARNING: Replace the anode if its diameter is less than 10 mm. The anode protects the tank from aggressive chemical substances in the water.

Draining the Product:

1. Shut down the system and switch off the control fuse.
2. Turn off the cold water supply.
3. Depressurize the buffer tank to less than 0.5 bar.
4. Open a domestic hot water tap to release pressure.
5. Open the drain valve for the DHW tank.

To refill, see section 3.5.3.

Spare Parts

Spare Parts List:

Diagram: A visual breakdown of the unit with numbered components corresponding to the spare parts list.

Warranty Conditions

Scope:

The Distributor warrants the product for 2 years from the date of purchase against defects in materials and workmanship, subject to conditions. Warranty applies to products purchased by consumers for private use and sold by the Distributor or a designated retailer. It does not apply to products purchased by commercial entities or for commercial use.

Coverage:

If a defect arises and a valid claim is received within the warranty period, the Distributor will, at their option, repair the defect, replace the product, or refund the purchase price.

Conditions:

• Product must be installed by a professional installer according to the manual and relevant codes/regulations.
• Product must not be modified, tampered with, misused, or have factory-fitted parts removed for unauthorized repair.
• Buffer tank must be filled with water compliant with European Drinking Water Directive EN 98/83 EC.
• DHW tank must be connected to a domestic water supply compliant with EN 98/83 EC. Water quality must not exceed: Chloride < 100 mg/l, Total Dissolved Solids < 200 mg/l, pH 6.0-9.5.
• If water quality exceeds these parameters, a sacrificial anode may be installed (see installation section). With an anode, limits are: Chloride < 250 mg/l, Total Dissolved Solids < 500 mg/l, pH 6.0-9.5.
• Disinfection must not affect the product. Isolate from system chlorination.
• Service/repair must follow the manual and codes. Use only original spare parts.
• Third-party costs must be authorized in advance by the Distributor.
• Provide purchase/installation/service invoices, water sample, and defective product upon request.

Failure to follow these conditions may result in product failure or leaks.

Limitations:

Warranty does not cover faults from incorrect installation, application, lack of maintenance, neglect, damage, misuse, unauthorized repair, consequential damage, connected pipework/equipment, effects of frost, lightning, voltage variation, dry boiling, excess pressure, chlorination, transport damage, or accessibility issues.

Recycling

Information for users on collection and disposal of old equipment:

Symbols on products, packaging, or documents indicate that used electrical and electronic products should not be mixed with general household waste. Dispose of products at applicable collection points according to national legislation and directives (2002/96 EC, 2006/66 EC). Proper disposal helps conserve resources and prevents negative environmental/health effects.

• For business users in the EU, contact your dealer or supplier.
• For disposal outside the EU, contact your local authorities or dealer.

Handover to End-User:

The installer must inform the end-user on safety, maintenance, and settings, and hand over this manual. Installer/electrician contact details should be filled in.

Installer/Electrician Information:

Form fields for Company Name, Name, Phone, Email, and Date of Installation/Connection for both Installer and Electrician.