How To Correct Heating System Corrosion?

Nothing will whip a homeowner into panic faster than discovering that their heating system has started corroding.

After all, rust can creep throughout your system, causing major damage.

However, there are distinctive tell-tale signs that your home’s heating system has corrosion. But what are they?

Signs Your Heating System Has Corrosion

You might be surprised to learn that there are multiple signs which can indicate your heating system has corrosion. These include the following:

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
• And 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.

In heating systems, sludge is what Gas Safe registered engineers call the thick, muddy deposits that build up within the system over time.

Sludge is a mixture of substances that include:

• Rust particles (iron oxide) from corroding radiators, pipes, and components
• Limescale (especially in hard water areas)
• Dirt and debris entering from the water supply or system leaks
• Magnetite (a fine black iron oxide, very common in older systems)

When sludge is allowed to build up, it can cause blockages, which will slow down your heating system’s performance or cause uneven heating across different rooms.

Noises

Your home’s boiler will make some noises when operating. However, if there is a buildup of sludge, it can cause your home’s boiler to make some strange noises. These noises include:

• Kettling (like a stove top kettle)
• Banging
• Gurgling
• Knocking
• And a general increase in noise from a strained circulation pump.

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.

Or if sludge has caused a blockage, causing the system’s pressure to increase unchecked, your boiler’s pressure relief valve (PRV) will start discharging water regularly.

Generally, if you can identify two or more of these signs, your heating system has some corrosion.

It’s natural to panic when you’ve discovered rust in your home’s heating system, but luckily, it is a common issue that can be corrected easily if caught early.

Let’s break down how it is dealt with.

How To Remove Corrosion From Your Heating System

Before fixing a corrosion problem, you need to know how it forms.

Identifying The Cause

Oxygen leaking into the system, or oxygen ingress, will cause rust to form. If your system has a leak or poor seals, oxygen has likely snuck in.

Electrolytic (or galvanic) corrosion happens when two different metals come into contact with each other in the presence of water (the electrolyte). This sets up a small electrical current between the metals, causing one metal to corrode faster.

This occurs when dissimilar metals aren’t properly isolated. As a home’s heating system is made up of multiple types of metal, which include:

• Copper pipes
• Steel radiators
• Aluminium heat exchangers
• Brass valves
• Cast iron components

If the coating on these metal components does come off, it will start to rust.

And the last cause is an imbalance of the pH level. If the water circulating through the system is overly acidic or alkaline, it will cause the metal to corrode.

Once you’re confident, you’ll want to call in a professional to drain the system and potentially power flush it.

Drain And Flush

To perform the repair work, the Gas Safe registered engineer will need to drain the system fully.

Depending on the issue, the professional will want to perform a power flush or chemical flush. This will ensure no debris is in the system when the repair is completed.

Or if the issue is a sludge blockage, the professional will perform the above procedure.

A power flush typically takes five to eight hours of work if your home has eight to twelve radiators. If your home has fewer radiators, it could be faster, and more will mean longer.

Other factors to consider that could lengthen the task are how heavily sludged the system is, whether you have old pipework, multiple zones, or underfloor heating.

A chemical flush is a lower-pressure, more passive treatment method for sludge. It generally takes one to two days to work. All that is required is to add the inhibitor or cleaner to the system, allow it to run for a day or two, drain the system, and refill via the boiler’s filling loop.

Replace Or Repair Affected Components

If components are too far corroded, a Gas Safe registered engineer will first replace or repair the affected component.

Components can be:

• Badly corroded radiators
• Pipework
• Valves
• Or heat exchangers within the boiler

If you’ve identified that the corrosion is due to a leaky seal or joint, they will either replace or repair the issue.

When refilling the system, the engineer will most likely add a high-quality inhibitor to prevent future corrosion issues. For homes in hard water areas, an engineer will add a scale reducer as well.

Checking The pH And Water Quality

A Gas Safe registered engineer will perform a water pH test before leaving the property. The ideal pH range is between 7.0 and 8.5.

The next check is to identify how much total dissolved solids (TDS) are in the system and how hard the water is.

Depending on the results, they will use an appropriate conditioner to adjust the pH levels. If there is a high amount of TDS in the water supply or if it is particularly hard, the engineer will most likely suggest installing a filter to remove these issues.

The engineer could also suggest installing an automatic air vent system to reduce oxygen ingress, or deaerators, which actively remove dissolved oxygen.

For homeowners looking to avoid this from happening in the future, make sure to:

• Schedule an annual system check by a certified Gas Safe registered engineer
• Top up on inhibitors every year, or when repressurising the system
• And conduct a quick pH test when you have time.

If you’re looking to schedule a service for your boiler, we can help!

Schedule An Annual Service Today!

WarmZilla is all about making boiler tasks as simple as possible. From selecting the right boiler to scheduling an annual service.

If you do need more assistance, we have professionals on standby to answer your questions.