Heating system corrosion is a common issue but fixable if caught early. Corrosion in your heating system can lead to rust, leaks, cold spots, odd noises, pressure fluctuations, and discoloured water. Identifying corrosion signs and understanding how it forms will help you take the necessary steps to fix and prevent it.
Signs Your Heating System Has Corrosion
You might be surprised to learn that there are multiple signs indicating your heating system has corrosion. These include:
Visual Signs
A visual sign is the most obvious indication that your heating system has started to corrode. Examples of visual signs include:
- Rust on radiator, pipe joints, or valves
- Leaks at joints or fittings
- Discoloured water when you bleed your radiators
If the heating system’s water is brown or black, it is a sure sign that rust is present in the network of pipes and radiators.
Performance Issues
If you’ve discovered cold spots on your radiator, usually at the bottom, it’s a sign that your heating system has built up sludge.
Sludge is a mixture of substances that include:
- Rust particles (iron oxide)
- Limescale
- Dirt and debris
- Magnetite (fine black iron oxide)
When sludge builds up, it causes blockages that can slow down your heating system’s performance and cause uneven heating.
Noises
Your home’s boiler will make some noises when operating. However, if there is a buildup of sludge, it can cause your boiler to make strange noises, including:
- Kettling
- Banging
- Gurgling
- Knocking
These noises indicate a stressed circulation pump due to the blockage.
Pressure Problems
For a boiler to work efficiently, the system needs to retain its pressure level. If you constantly repressurise your boiler, this could indicate a leak caused by unchecked corrosion.
If sludge has caused a blockage, the pressure will increase unchecked, leading to the pressure relief valve (PRV) discharging water regularly.
How To Remove Corrosion From Your Heating System
Identifying The Cause
- Oxygen ingress: Oxygen leaking into the system will cause rust to form.
- Electrolytic corrosion: This happens when two different metals come into contact in the presence of water (electrolyte), causing one to corrode faster.
- pH imbalance: An overly acidic or alkaline pH level in the water causes the metal to corrode.
Drain And Flush
To fix the problem, the system needs to be drained. A power flush or chemical flush is used to remove the sludge and debris.
A power flush typically takes five to eight hours, depending on the number of radiators and the severity of sludge.
Replace Or Repair Affected Components
If parts are too far corroded, they will need to be replaced. Commonly replaced components include:
- Radiators
- Pipework
- Valves
- Heat exchangers
Checking The pH And Water Quality
A professional will perform a water pH test, aiming for a pH between 7.0 and 8.5. If necessary, a filter or air vent system will be installed to reduce oxygen ingress and remove harmful particles.
When to Call a Professional
If you cannot fix the issue with these methods, it’s time to call a professional plumber. Regular annual check-ups and maintenance can help prevent heating system corrosion from becoming a larger issue.
Frequently asked questions
Heating system corrosion is typically caused by oxygen ingress, electrolytic corrosion, or an imbalance in the pH level of the water. These issues lead to rust and debris buildup.
Signs of heating system corrosion include rust on components, leaks, discoloured water, and performance issues like cold spots and strange boiler noises.
You can fix it by draining the system and performing a power flush or chemical flush to remove sludge. Corroded components may need to be replaced, and inhibitors should be added to prevent future corrosion.
