Power Flushing Cardiff
Cold Spots, Slow Heating & Sludged Systems
Whether your system needs a full power flush, a less invasive chemical flush, or just a magnetic filter to capture sludge going forward, our heating engineers handle the full range of system cleaning work.
Book an Engineer →Your Local Plumber in Cardiff
We’re local Cardiff heating engineers carrying out power flushing using quality inhibitors and thorough diagnosis.
Gas Safe Registered (518700)
NJ Harkus is Gas Safe registered (518700), City & Guilds qualified and CIPHE members, with full public liability insurance for all plumbing, heating and gas work.
Highly Recommended & Reviewed
From sludged-up old systems to pre-installation flushes for new boilers, customers rely on us to do it right.
Complete Power Flushing Services
Full System Flushes, Chemical Flushes & Magnetic Filter Installation
Every system cleaning job starts with proper diagnosis. From there, we recommend the right service for the system, whether that’s a full power flush, a less invasive chemical clean, or simply a magnetic filter to capture sludge going forward.
Our power flushing services include:
- Full system power flushing
- Individual radiator flushing for localised sludge
- Chemical flushing for less invasive system cleaning
- Magnetic filter installation (Magnaclean, Fernox)
- System inhibitor top-up and replacement
- Pre-installation flushing for new boilers
- Diagnosis of cold spots and circulation issues
- Pump and valve checks during the flushing process
- Post-flush system balancing
- Manufacturer warranty-compliant flushing for new boilers
Need A Power Flush or Not Sure?
Power Flushing Across Cardiff & Nearby
We carry out power flushing across Cardiff and the surrounding areas, including Penarth, Sully, Barry, Cowbridge, Pontyclun, Llantrisant, and Dinas Powys. From single-radiator flushes on smaller systems to full whole-house jobs on older properties with years of sludge build-up, our team handles the work properly, whatever the system.
Business Hours
24 Hours, 7 Days A Week
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We Are Highly Recommended in Cardiff & The Surrounding Areas
Magnetic Filter Installation
The Best Way To Protect A Newly Cleaned System
A magnetic filter is one of the most worthwhile upgrades you can make to a heating system. Fitted to the return pipe near the boiler, it uses a powerful magnet to capture the iron-oxide sludge that naturally forms in heating systems before it can settle in radiators or damage the boiler. At NJ Harkus, we regularly service the filter during boiler servicing to remove what it has captured.
Most modern boiler installations should come with one as standard, but plenty of older systems don’t have one, and many newer installations skip them to save costs. Fitting one to an existing system is a straightforward job, usually done in an hour, and it can dramatically extend how long the system stays clean.
If you’ve recently had a power flush or are planning a new boiler, a magnetic filter is genuinely one of the smartest add-ons to consider. We usually fit Magnaclean, Fernox Total Filter, and similar leading brands.
Want a magnetic filter fitted to your system? Get in touch, and we’ll come and have a look.
Frequently Asked Questions
Our Power Flushing FAQs
How do I know if my heating system needs a power flush?
The most common signs are cold spots on radiators (particularly at the bottom), radiators that take a long time to heat up, a boiler that keeps cutting out or making unusual noises, and water from a bled radiator coming out brown or black instead of clear. If you’re seeing any of these, the system is likely sludged up.
At NJ Harkus, we always diagnose any issues before recommending a flush.
Is power flushing required before a new boiler installation?
Most boiler manufacturers require either a power flush or a thorough chemical clean of the existing system before installing a new boiler, particularly if you want to keep the manufacturer’s warranty valid. We regularly carry out warranty-compliant flushing as part of new boiler installations.
Will the system need anything done afterwards?
Yes. After flushing, the system needs fresh water with the correct inhibitor (Sentinel X100 or similar) added to prevent corrosion from starting again. We always include this. We’d also usually recommend installing a magnetic filter so any future sludge gets captured rather than re-circulating. That’s how you make a flush actually last.
Can you flush just one radiator instead of the whole system?
Sometimes, yes. Individual radiator flushes work where sludge has built up in just one or two radiators while the rest of the system is fine. We’ll check the whole system first to make sure the problem really is localised before recommending a single-radiator flush.
