Product Description

BWT WS355 14 Litre Water Softener with 15mm or 22mm Installation Kit

Model: BWT WS355

Enjoy softer water throughout your home with the BWT WS355 14 Litre Water Softener. BWT designed this compact electronic water softener for UK homes with standard 15mm plumbing systems.

The WS355 removes the calcium and magnesium minerals that cause limescale and soap scum. As a result, it helps protect compatible boilers, hot-water cylinders, taps, showers and household appliances from scale build-up.

Its modern electronic control system monitors water use and regenerates the softener when needed. Therefore, the WS355 can reduce unnecessary salt and water use while maintaining a reliable supply of softened water.

The BWT WS355 suits households of up to six people.

Key Features

• 14-litre domestic water softener
• Suitable for households of up to six people
• Supplied with a 15mm installation kit or 22mm option
• Compact design for easier installation
• Electronic demand-based control system
• Proportional brining helps reduce salt and water use
• Reliable rotary control valve
• Maximum softened-water capacity of 2,500 litres
• Operating flow range of 10 to 30 litres per minute
• 16kg tablet-salt storage capacity
• Free BWT home commissioning available
• Five-year parts warranty
• Two-year at-home labour warranty
• Designed for UK homes and plumbing systems
• WRAS-approved water softener
• Product model: BWT WS355

BWT WS355 Specification

• Download the BWT WS Series Installation Manual
• Brand: BWT
• Product type: electronic domestic water softener
• Model: WS355
• Nominal product size: 14 litres
• Recommended household size: up to 6 people
• Installation kit: 15mm valves and flexible hoses
• Nominal inlet and outlet connection: ¾-inch BSP
• Drain connection: ½-inch tube
• Operating flow range: 10 to 30 litres per minute
• Nominal flow rate: 1,560 litres per hour
• Maximum softened-water capacity: 2,500 litres
• Salt use per regeneration: approximately 1.2 to 2.4kg
• Water use per regeneration: less than 80 litres
• Salt storage capacity: 16kg
• Compatible salt type: tablet salt
• Minimum operating pressure: 1.7 bar
• Maximum operating pressure: 5 bar
• Minimum water temperature: 5°C
• Maximum water temperature: 49°C
• Electrical supply: 230V plug-in transformer with 12V low-voltage output
• Protection class: IP51
• Warranty: 5 years on parts and 2 years at-home labour

What Is Included?

• 1 x BWT WS355 electronic water softener
• 15mm valves and flexible connection hoses
• Low-voltage plug-in transformer
• Installation and operating instructions
• Access to BWT’s free home commissioning service, subject to BWT’s terms

Please note: Overflow pipe, drain pipe, salt and any extra fittings needed for a non-standard installation may need to be purchased separately.

Will the BWT WS355 Fit in My Space?

• Height: 602mm
• Width: 270mm
• Depth: 480mm
• Connection height: approximately 415mm
• Overflow height: approximately 320mm
• Approximate operating weight: 50kg

The narrow 270mm body makes the WS355 suitable for many kitchen cupboards and utility areas. However, allow extra space for the hoses, drain, overflow, electrical lead and salt filling.

In addition, make sure you can lift the lid and reach the controls after installation. Always measure the full available space before ordering.

Free BWT Home Commissioning

BWT offers free at-home commissioning with the WS355, subject to its current service terms and availability.

First, your installer fits the water softener, connects the required services and completes the initial setup. Then, a trained BWT engineer can visit your home to commission the unit for your local water hardness and normal household water use.

The service gives you several useful benefits:

• A BWT engineer checks the main operating settings
• The softener can be adjusted for local water hardness
• The settings can match your household’s water use
• You can ask questions about operation and salt filling
• Your installer can focus on completing the plumbing work
• Correct setup can help reduce unnecessary water and salt use

You may need to register the product and arrange the appointment directly with BWT. Therefore, check the latest commissioning instructions after purchase.

How Does the BWT WS355 Work?

The WS355 uses ion-exchange resin to remove the calcium and magnesium minerals that cause hard water. The resin holds these hardness minerals as the incoming mains water passes through the softener.

Once the resin reaches a set capacity, the electronic controller starts a regeneration cycle. During this process, a salt solution cleans the resin and prepares it to soften more water.

Because the WS355 monitors demand, it regenerates according to water use rather than relying only on a basic timer. As a result, it can use salt and water more efficiently.

Benefits of Softened Water

• Helps reduce limescale around taps and shower fittings
• Helps protect compatible boilers and hot-water cylinders
• Helps protect washing machines and dishwashers from scale
• Reduces soap scum on baths, basins and shower screens
• Allows soaps and shampoos to lather more easily
• Can reduce the amount of cleaning product required
• Makes scale deposits easier to control
• Helps maintain water flow through compatible appliances and fittings

Results can vary according to the incoming water hardness, household water use and how the unit is set up. In addition, always check that connected appliances can receive fully softened water.

Electronic Demand Control

The electronic controller monitors household water demand and calculates when regeneration is needed. Therefore, the softener does not regenerate simply because a fixed amount of time has passed.

The controller also uses proportional brining. This means it calculates the amount of salt and water needed for each regeneration cycle. As a result, a partial regeneration may use less salt than a full regeneration.

Power-Cut Memory

The controller includes a memory backup that can retain key settings during a temporary interruption to the electrical supply. This helps the softener return to normal operation without losing its main setup information.

However, check the time and display after a longer power cut. Reset them if required by the operating instructions.

Suitable Plumbing Systems

The standard WS355 with a 15mm kit suits many UK homes with conventional 15mm incoming plumbing. It can work alongside compatible systems such as:

• Combination boilers
• Vented hot-water cylinders
• Unvented hot-water cylinders
• Gravity-fed hot-water systems
• Compatible domestic plumbing appliances

However, some boilers, heating appliances and specialist drinking-water systems may have their own water-quality requirements. Therefore, always check the appliance manufacturer’s instructions before connecting softened water.

15mm Installation Kit

This version comes with a standard 15mm installation kit, including valves and flexible hoses. The kit helps connect the softener to a compatible 15mm plumbing system.

If your home has 22mm pipework or requires a higher flow rate, consider the BWT WS355 High Flow model or a suitable 22mm installation kit instead. Ask your installer to check the incoming main, expected peak demand and available pressure before ordering.

Installation Requirements

Install the WS355 close to the incoming mains-water supply and main stopcock. The chosen position will also need:

• A suitable 15mm cold-water supply
• A drain connection for regeneration water
• A safe overflow route
• A nearby standard electrical socket
• A firm and level floor
• Enough space to fill the salt reservoir
• Access for servicing and future maintenance

Do not install the softener where it may freeze or face extreme heat. In addition, protect the electrical transformer and socket from water.

A competent installer should complete the plumbing work. The installation must follow the BWT instructions, Water Supply Regulations and all other relevant requirements.

Drinking-Water Supply

The installation may require a separate unsoftened drinking-water tap, depending on local requirements and household needs. This is especially important for people who must control their sodium intake and for preparing infant formula.

Ask your installer to confirm the correct arrangement for your property before fitting the softener.

Salt and Routine Maintenance

Use suitable BWT tablet salt or another tablet salt approved for domestic water softeners. Check the salt level regularly and refill the reservoir before it becomes empty.

For reliable operation:

• Keep the salt level above the minimum shown in the instructions
• Use clean water-softener tablet salt
• Keep the salt reservoir lid closed
• Check occasionally for salt bridging
• Keep the drain and overflow routes clear
• Check hoses and valves for leaks
• Arrange servicing when required

The amount of salt used will depend on local water hardness, household demand and the amount of resin that needs regenerating.

BWT Warranty

The BWT WS355 includes a five-year parts warranty and a two-year at-home labour warranty, subject to BWT’s terms and conditions.

Register the product after installation and keep your proof of purchase. Correct installation, commissioning, salt use and maintenance may affect warranty cover.

Why Choose the BWT WS355?

The WS355 combines a compact body with electronic demand control, proportional brining and a reliable rotary valve. Therefore, it provides an efficient water-softening solution for many medium and larger UK households.

In addition, BWT supports the product with free home commissioning and an at-home warranty. This gives homeowners added help with setup, operation and after-sales care.

Why Buy from SNH Tradecentre?

• Experienced plumbing and water-treatment merchant
• Practical advice before you order
• Help choosing between 15mm and 22mm models
• Fast UK delivery options
• Click and collect from our Birchington trade counter
• Matching water-softener salt and installation accessories
• Secure online ordering
• Support before and after your purchase

If you need help checking the size or flow rate, contact SNH Tradecentre before ordering. Let us know the number of people in your home, the number of bathrooms and whether your incoming water main uses 15mm or 22mm pipework.