Central Heating Chemicals

About Central Heating Chemicals

Central heating chemicals are essential maintenance products designed to keep your heating system running efficiently, reliably and economically. These specialist formulations include system cleansers that remove sludge, limescale and corrosion deposits, as well as inhibitors that provide ongoing protection against future deterioration. Whether you're commissioning a new system, carrying out routine maintenance, or troubleshooting performance issues, the right central heating chemicals can significantly extend the lifespan of boilers, radiators, pipes and pumps whilst reducing energy consumption and preventing costly breakdowns.

A properly maintained central heating system with appropriate chemical treatment can operate up to 15% more efficiently than an untreated system. Over time, heating systems accumulate iron oxide sludge (commonly known as magnetite), limescale deposits from hard water areas, and general corrosion products that restrict flow, reduce heat transfer efficiency, and cause premature component failure. System cleansers work by breaking down and suspending these deposits so they can be flushed out, whilst inhibitors form a protective layer on internal surfaces to prevent further corrosion and scale formation.

Our range includes trusted products from Everbuild, a leading manufacturer of building chemicals used by heating engineers and plumbers across the UK. From powerful system cleansers like the P11 formula that prepares systems for optimal performance, to long-lasting inhibitors such as the P14 treatment that protects against corrosion and limescale, these products represent professional-grade solutions for both new installations and existing system maintenance.

Jargon Buster

• System Cleanser: A chemical formulation designed to remove existing sludge, rust, limescale and other debris from central heating systems. Typically circulated through the system for several hours before being flushed out completely prior to refilling.
• System Inhibitor: A protective chemical added to central heating water to prevent internal corrosion, limescale formation and bacterial growth. Remains in the system long-term, typically requiring renewal every 5-10 years or when the system is drained.
• Magnetite: Black iron oxide sludge that forms through corrosion of steel radiators and pipework. Accumulates in low-flow areas and can cause blocked pipes, noisy pumps, cold spots on radiators and boiler failure.
• Limescale: Calcium carbonate deposits that precipitate from hard water when heated. Can coat heat exchangers, reducing efficiency and potentially causing boiler overheating and failure, particularly problematic in hard water areas across the South East and East of England.
• Power Flushing: A thorough cleaning process using specialist equipment to force cleaning chemicals and water through the system at high velocity, removing stubborn deposits. Often performed before applying fresh inhibitor.
• Dosing: The process of adding the correct quantity of chemical to a heating system, typically via a radiator, filling loop, or dedicated dosing point. Correct dosing rates are critical for effective protection.

Who Uses Central Heating Chemicals?

Central heating chemicals are essential for a variety of professionals and situations:

• Heating Engineers and Gas Safe Registered Technicians: Using cleansers during system commissioning, annual services and repair work
• Plumbers and Plumbing & Heating Installers: Adding inhibitors to new installations and during system modifications
• Maintenance Contractors: Carrying out preventative maintenance on commercial and residential heating systems
• Landlords and Property Managers: Maintaining heating systems in rental properties to meet legal obligations and prevent tenant complaints
• Facilities Managers: Responsible for heating system performance in commercial buildings, schools and public facilities
• Competent DIY Enthusiasts: Maintaining their own domestic heating systems to improve efficiency and prevent costly repairs
• Boiler Manufacturers and Warranty Providers: Often require proof of inhibitor treatment to validate warranties on new boilers

How to Choose the Right Central Heating Chemicals

Selecting the appropriate central heating chemical depends on several key factors:

System Condition: For older systems showing signs of poor circulation, cold spots, or discoloured water when bled, start with a thorough system cleanser like the Everbuild P11. New or recently cleaned systems require only an inhibitor for ongoing protection. If you're unsure, checking the colour of water from radiator bleed valves provides a good indication—dark, murky water suggests cleaning is needed.

Water Hardness: Properties in hard water areas (particularly South East England, East Anglia and parts of the Midlands) require inhibitors with enhanced limescale protection. Check your local water authority's hardness rating or look for visible scale deposits on kettles and taps as an indicator.

System Type and Materials: Ensure compatibility with your system components. Modern systems may contain aluminium heat exchangers in combination boilers, whilst older systems typically feature all-steel construction. Quality inhibitors like Everbuild P14 are formulated to protect mixed-metal systems safely.

System Volume: Calculate your system's capacity to determine the correct quantity of chemical required. As a rough guide, a typical three-bedroom house has a system volume of 80-120 litres. Product packaging provides clear dosing instructions based on system volume.

Boiler Warranty Requirements: Many boiler manufacturers stipulate annual inhibitor checks and renewal as a warranty condition. Always check your boiler documentation and use products meeting relevant British Standards to maintain warranty validity.

Popular Accessories

• Magnetic System Filters: Capture magnetite particles before they circulate through the system, working alongside chemical treatment for maximum protection
• Dosing Bottles and Measuring Jugs: Ensure accurate chemical dosing for optimal protection without waste
• Radiator Keys: Essential for bleeding radiators before and after chemical treatment
• TDS Meters: Test instruments for checking inhibitor concentration levels during maintenance visits
• Flushing Pumps: Professional equipment for power flushing when using system cleansers
• Water Test Kits: Check pH levels and inhibitor concentration to determine when system requires retreatment
• Filling Loop Connectors: Facilitate easier dosing of chemicals into sealed heating systems
• Bucket and Hose: Essential for draining down and flushing procedures

Safety Information

Central heating chemicals require careful handling and appropriate precautions:

Personal Protection: Always wear appropriate PPE including chemical-resistant gloves and eye protection when handling concentrated products. Splashes can cause skin and eye irritation. Ensure adequate ventilation when working with these chemicals, particularly in confined spaces.

COSHH Compliance: Professional users must conduct COSHH (Control of Substances Hazardous to Health) assessments before using these products. Familiarise yourself with the product safety data sheet (SDS) available from the manufacturer, which details hazards, safe handling procedures and emergency measures.

Storage: Store chemicals in original containers with labels intact, away from children, pets and foodstuffs. Keep in a cool, dry place away from direct sunlight. Never decant into unlabelled containers or drinks bottles.

Disposal: Spent cleaning chemicals and contaminated flush water must be disposed of responsibly according to local authority regulations. Never discharge directly into watercourses or drains without appropriate neutralisation. Contact your local water authority for guidance on disposal of larger quantities.

System Safety: Ensure heating systems are switched off and cooled before draining or adding chemicals. Be aware of pressure release when opening filling loops or radiator valves. After treatment, check all connections for leaks before leaving the system unattended.

Frequently Asked Questions

How often should I add inhibitor to my central heating system?

System inhibitor should be checked annually during boiler servicing and topped up if necessary. A complete system drain and fresh inhibitor dose is typically required every 5-10 years, or whenever significant work is carried out that involves draining the system. Many modern boiler warranties require annual verification that adequate inhibitor is present.

Can I add central heating chemicals myself or do I need a professional?

Competent DIYers can add inhibitor to their own systems following manufacturer instructions carefully. However, system cleansing often requires professional equipment and expertise, particularly power flushing. Any work involving gas boilers must be carried out by Gas Safe registered engineers. If you're unsure about system volume calculations or dosing procedures, consult a heating professional.

What's the difference between a cleanser and an inhibitor?

A system cleanser is a temporary treatment that actively removes existing deposits, sludge and scale. It's circulated through the system for several hours then completely flushed out before refilling. An inhibitor is a long-term protective treatment that remains in the system water to prevent future corrosion and scale formation. Think of cleansing as a deep clean, whilst inhibitor is ongoing protection—most systems benefit from both.

Will central heating chemicals fix noisy radiators and boilers?

Noise caused by sludge buildup, scale deposits or trapped air can often be resolved with appropriate chemical treatment. System cleanser removes deposits that cause kettling sounds in boilers and gurgling in radiators. However, mechanical issues like faulty pumps or incorrectly sized pipework require physical repairs. If noise persists after chemical treatment and bleeding radiators, consult a heating engineer.

How do I know if my heating system needs cleaning?

Common signs include cold spots on radiators (particularly at the bottom), some radiators heating poorly whilst others work fine, excessive noise from the boiler or radiators, frequent boiler shutdowns, slow heating response, increased energy bills, or black/brown water when bleeding radiators. Systems over 5 years old without previous treatment almost certainly benefit from cleaning and fresh inhibitor.