Watts NF-ACS Brass Right 1/2" (15/21) Safety Group Instruction Manual

1. Introduction

This instruction manual provides essential information for the safe and efficient installation, operation, and maintenance of the Watts NF-ACS Brass Right 1/2" (15/21) Safety Group, model NA53M2. This safety group is designed to protect small capacity domestic hot water cylinders (10 to 50 liters) from excessive pressure, ensuring the longevity and safe operation of your water heating system. Please read this manual thoroughly before installation and keep it for future reference.

2. Product Overview

The Watts NA53M2 Safety Group is a critical component for domestic hot water installations. It features a 1/2 inch (15 x 21) connection, making it suitable for compact setups, typically installed on or under the sink. Its robust brass construction ensures durability and compliance with relevant safety standards.

• Model: NA53M2
• Part Number: 2254310M3
• Connection Size: 1/2 inch (15 x 21)
• Application: Small capacity domestic hot water cylinders (10 to 50 liters)
• Maximum Power: Suitable for cylinders up to 4 kW
• Orientation: Right-hand configuration
• Included: Plastic air protection DN 20
• Compliance: NF EN 1487 & Belgaqua standards

Figure 1: Main view of the Watts NF-ACS Brass Right 1/2 inch Safety Group. This image shows the brass body, the red pressure adjustment cap, and the black manual relief lever.

3. Safety Information

Always adhere to local regulations and safety standards during installation and operation. Failure to do so may result in property damage, injury, or death.

• Professional Installation: Installation should only be performed by a qualified plumber or technician.
• Water Supply: Ensure the main water supply is turned off before commencing any installation or maintenance work.
• Pressure: The safety group is designed to manage pressure. Do not tamper with its internal components.
• Temperature: Be aware of hot water temperatures during operation and maintenance.
• Drainage: Ensure proper drainage for discharged water.

4. Setup and Installation

The Watts NA53M2 Safety Group is designed for installation on the cold water inlet of a domestic hot water cylinder. It is particularly suitable for installations where the cylinder is located on or under the sink, or above the sink/under the worktop.

1. Preparation: Turn off the main water supply and drain the hot water cylinder if necessary.
2. Connection: Connect the 1/2 inch (15 x 21) inlet of the safety group to the cold water supply line. Ensure all connections are sealed properly using appropriate plumbing tape or sealant.
3. Cylinder Connection: Connect the outlet of the safety group to the cold water inlet of the hot water cylinder.
4. Drainage: Attach a suitable drain pipe to the discharge outlet of the safety group. This pipe must be routed to an open drain, allowing for visible discharge and preventing backpressure. The supplied plastic air protection DN 20 should be used to ensure an air gap.
5. Orientation: This is a right-hand safety group. Ensure it is installed in the correct orientation as per your plumbing setup.
6. Special Recommendation: For 'stable' or 'horizontal' instantaneous water heaters, this safety group is highly recommended due to its design which helps mitigate issues with calcification and blockages from impurities like sand and limescale.
7. Final Check: Once all connections are secure, slowly open the main water supply and check for any leaks.

Figure 2: Alternative view of the Watts NF-ACS Brass Right 1/2 inch Safety Group, possibly showing the drain connection and the plastic air protection component.

5. Operating Instructions

The Watts NA53M2 Safety Group operates automatically to relieve excess pressure in your hot water cylinder. During the heating cycle, water expands, causing pressure to build up. The safety group will discharge small amounts of water to maintain a safe operating pressure. This dripping is normal and indicates proper function.

• Automatic Operation: The valve automatically opens to release pressure when it exceeds the set limit.
• Manual Operation: The black lever on the safety group allows for manual operation of the relief valve. This is primarily used for maintenance purposes (see Section 6).
• Normal Dripping: It is normal for the safety group to drip water into the drain during the water heating cycle. This is a sign that the unit is functioning correctly by relieving excess pressure.

6. Maintenance

Regular maintenance ensures the continued safe and efficient operation of your Watts NA53M2 Safety Group.

• Monthly Manual Test: At least once a month, manually operate the relief valve by lifting the black lever for a few seconds. This flushes out any potential debris or limescale buildup, preventing the valve from sticking. Ensure water flows freely from the discharge pipe during this test.
• Visual Inspection: Periodically inspect the safety group and its connections for any signs of leaks, corrosion, or damage.
• Drainage Check: Ensure the drain pipe is clear and free from obstructions.
• Cleaning: Clean the exterior of the unit with a damp cloth. Do not use abrasive cleaners or solvents.

7. Troubleshooting

Refer to the following common issues and solutions before contacting a professional.

8. Specifications

9. Warranty and Support

Specific warranty terms and conditions for the Watts NA53M2 Safety Group are provided by the manufacturer at the time of purchase. Please refer to your purchase documentation or contact your retailer for detailed warranty information.

For technical support or further assistance, please contact Watts customer service or your authorized dealer. Ensure you have your model number (NA53M2) and part number (2254310M3) available when seeking support.