Up to 6 rads
Quoted
Full chemical flush + inhibitor refresh
- Sentinel X400 cleaning chemical
- High-flow Kamco-pattern flush pump
- Reverse-cycle every radiator individually
- Sentinel X100 inhibitor refresh
- Magnetic plug + filter clean
Plumbing
Powerflushing
Full system powerflush to remove sludge from radiators and pipework, improving efficiency, restoring cold spots, and protecting the boiler. Honest assessment first.
Pricing Quoted
Clear quote · Gas Safe registered · Checkatrade approved
- 1Send the detailsPhotos, postcode, what's happening: phone, WhatsApp or form.
- 2Same-day replyNigel confirms price, visit time or survey slot.
- 3Fixed quoteWritten down before any work starts. No surprises.
Indicative scope
Exact pricing is confirmed before work starts and depends on the property, access, parts and fault diagnosis.
7–10 rads
Quoted
Full flush including MagnaClean retrofit
- Everything in the 6-rad tier
- MagnaClean Pro2 fitted (saves £140)
- Full system balance after
- Worcester / Vaillant warranty preserved
- 12-month workmanship warranty
11+ rads
Quoted
Larger systems, quoted on rad count
- Same chemical and procedure
- Larger volume of cleaning chemical
- Longer cycle time
- All fittings recommissioned
- Includes inhibitor refresh
Powerflush
Cold-at-the-bottom radiators or short-cycling boiler?
Full system powerflush to remove sludge from radiators and pipework, improving efficiency, restoring cold spots, and protecting the boiler. Honest assessment first.
At a glance
Quick facts before you read on.
What's included
5 things, no extras on the day- Sentinel X400 cleaning chemical
- High-flow Kamco-pattern flush pump
- Reverse-cycle every radiator individually
- Sentinel X100 inhibitor refresh
How we quote
Confirmed before work startsUp to 6 radiators, full chemical flush + inhibitor refresh.
Certification
Gas Safe RegisteredJob done to standards. Paperwork on the day.
Service area
Cardiff, Penarth, Barry, CaerphillySludge, the black iron-oxide gunge that builds up in central heating systems, is the single biggest cause of poor radiator performance and premature boiler failure. A powerflush forcibly cycles cleaning chemicals through every radiator and the entire pipework, then flushes the contamination out and refills with fresh inhibitor.
But not every system needs one. We’ll diagnose properly first.
What we do
- Drop the existing inhibitor and replace with a powerflush chemical (Sentinel X400 or Fernox F5).
- Mount a high-flow Kamco-pattern pump at the boiler tails and reverse the flow direction repeatedly across each radiator.
- Sample the discharged water until it runs clean. Usually 4–8 hours of work depending on system age and rad count.
- Refill with fresh inhibitor (Sentinel X100 to manufacturer spec, typically 1L per 100L of system volume).
- Fit a magnetic system filter (MagnaClean Pro2 or equivalent) if you don’t already have one. Required for most modern boiler warranties.
Pricing
| Property size | Price |
|---|---|
| Up to 6 radiators | £480 |
| 7–10 radiators | £580 (incl. MagnaClean) |
| 11+ radiators | £680+ |
| Add MagnaClean filter | £140 (free in 7–10 rad tier) |
| Add system balance | included in every tier |
Will my system actually need one?
Sometimes no. We’ll always look first: a real diagnostic visit is £90 and credits against the work if you go ahead.
In roughly 1 in 4 systems we look at, a magnetic filter retrofit, fresh inhibitor, and a balance will fix the symptoms for £280 instead of £480. We’ll quote that, not the flush, when it’s the right answer.
The signs that point to a real flush case (not a balance/filter case) are:
- Multiple radiators cold at the bottom even after bleeding.
- Boiler short-cycling and pressure rising during operation.
- System water running visibly black when you bleed a radiator.
- High iron content on a magnetic test (we carry a portable kit).
- A system that hasn’t been touched in 8+ years with no inhibitor or filter.
The signs that point to balance/filter only (no flush needed):
- Radiators slow to heat but eventually do, and feel even top-to-bottom.
- Water is dark grey but not black.
- System has been working “ok” but boiler short-cycles slightly.
- Inhibitor was added in the last 3–4 years.
What a powerflush won’t fix
Honest list:
- A failing pump: flushing won’t bring it back, just delay the inevitable.
- A leaking heat exchanger: flushing won’t seal a pinhole leak.
- Undersized radiators: flushing restores their rated output, but if the rated output was always too low for the room, the room will still run cool.
- A noisy boiler with kettling: sometimes flushing fixes it (sludge on the heat exchanger), sometimes the heat exchanger is permanently scaled and a swap is the only option.
Common mistakes other firms make
- Quoting a flush before looking. Diagnostic-first is non-negotiable.
- Skipping the inhibitor refresh. A flush without proper inhibitor concentration sets you up for the same problem in 3 years.
- Not balancing after. A flush leaves the system better but still asymmetric without re-balance.
- Using cheap chemicals. We only use Sentinel or Fernox products to manufacturer spec. Generic “system cleaner” from the merchant is not the same.
Workmanship and warranty
12-month workmanship warranty on every flush. We preserve manufacturer warranties on Worcester, Vaillant, Viessmann, Ideal, Baxi and Glow-worm boilers: the install certificate updates the manufacturer portal automatically.
Three firms quoted me a new boiler, £3,500 they said. Nigel came out, spent 90 minutes diagnosing it, said the boiler was fine, the system was full of sludge. Powerflushed it for £580 and the heating's been perfect for 18 months. Saved me three grand. Honesty is the rare bit.
Recent jobs near you
A few of the jobs we have finished lately, with the postcode and what was involved.
- CF24 April
8-rad Roath terrace, full flush + MagnaClean. Saved customer a £3,500 boiler quote.
- CF14 April
Whitchurch detached, 12 rads, full flush. Heat output recovered across upstairs.
- CF11 March
Pontcanna 4-bed, flush + 3 new TRVs. Boiler stopped short-cycling.
- CF83 March
Caerphilly bungalow, 6 rads, sub-£500 flush. System restored.
- CF64 February
Penarth detached, diagnosed as filter-and-refresh case, saved £200 vs flush.
How the job runs
- 01
Diagnostic visit
60–90 minWe test water iron content, take flow + return temps, touch every rad. You get an honest assessment of whether it needs a flush, a balance, or just a filter, before any quote.
- 02
Pre-flush prep
30 minExisting inhibitor drained off. Cleaning chemical (Sentinel X400 or Fernox F5) added. System runs hot for 30 minutes to mobilise the sludge.
- 03
Flush cycle
4–6 hoursHigh-flow pump connected at boiler tails. Reverse-cycle every radiator individually. Discharge sampled every 30 minutes. We continue until water runs clean.
- 04
Refill + balance
60 minFresh Sentinel X100 inhibitor added to manufacturer spec. System balanced, every radiator brought up to temperature. Magnetic filter (if fitted) cleaned and tested.
- 05
Recommission
30 minBoiler recommissioned, gas-tightness re-tested, controls reset. Full Gas Safety Certificate issued where work touched the boiler.
Common questions
How long does a boiler installation take?
A like-for-like combi swap is usually a single working day. System or regular boiler upgrades, or installs that need the flue rerouted, take one to two days. Back-boiler removals add half a day for the chimney sweep and asbestos check. We'll give you a firm timeline at quote stage so you can plan around it.
Which boiler brand should I pick?
PHBLUE's existing site says we service and repair all major boiler makes and models, including Worcester Bosch, Vaillant, Ideal and Baxi. The right brand depends on the house, budget, warranty and parts availability, so we confirm the recommendation in the quote.
What's included in a fixed-price boiler quote?
A written boiler quote should set out the boiler, flue work, controls, any filter or system-cleaning work, warranty position, registration requirements and removal of the old unit where included. We confirm the exact scope before work starts.
How much should a new boiler cost in 2026?
Boiler prices depend on the model, flue route, controls, system condition, access and whether extra pipework or cleaning is needed. Send the boiler details and postcode and we will confirm the price before work starts.
Will you remove the old boiler?
Yes, every install includes removal and recycling of the old unit, packaging take-away, and a full clean-down before we leave. You'll get the warranty paperwork and the Gas Safety Certificate handed to you on the day.
Do you service boilers you didn't install?
Yes. The existing PHBLUE site says we service and repair all boiler makes and models, including Worcester Bosch, Vaillant, Ideal, Baxi and more.
How much does a new bathroom cost in Cardiff?
For a standard 3-piece bathroom (bath, basin, WC) refit including tiling, flooring and second-fix electrics: £6,500–£9,500 fitted, depending on tile choice and whether the layout moves. Wet rooms and en-suites with shower trays start £8,500. We quote fully fixed-price after a survey; supply-only items are at trade plus 10%.
How long does a bathroom installation take?
A straight refit (same layout, same waste positions) is 5–7 working days. Layout changes that need waste pipe reroutes add 2–3 days. We work clean: dust sheets up, daily clean-down, the rest of the house stays liveable.
Do you do tap repairs or just full installs?
Both. Most tap drips are a £20 cartridge, and we charge £90 for the first hour (covers diagnosis and most repairs) and £55 per hour after. If your taps are end-of-life we'll tell you and quote a swap, never the other way round.
What's the difference between a powerflush and a magnetic filter?
A powerflush is a one-time deep clean of the heating system using a high-flow pump and inhibitor, which clears years of magnetite sludge from radiators, boilers and pipework. A magnetic filter (MagnaClean or equivalent) is fitted permanently on the return pipe and traps sludge as it circulates, year on year. Both are needed for a long-lasting modern system. Powerflush £450; magnetic filter retrofit £180 fitted.
My water pressure is low, can you help?
Yes, first we'll find out whether it's coming in low (a problem with the incoming main, your stopcock, or a partially-closed valve), or dropping mid-house (a leak, a cylinder issue, or scale in the pipework). Diagnostic visit is £90 and gets credited if you go on to have the work done.
Are you WaterSafe registered?
Yes: WaterSafe approved plumber scheme. That's the recognised standard for any work that touches the mains supply (stopcocks, incoming mains repairs, unvented cylinders, water softeners). It's also the scheme insurers and conveyancers look for on home reports.
Do you charge a call-out fee?
No, not for any job we go on to quote or carry out. Diagnostic visits where we don't end up doing work are charged at our standard hourly rate (£90 first hour, £55 after) and we'll always tell you that up front.
Are quotes fixed price or estimates?
Fixed-price for everything we can survey: boiler installs, bathrooms, EV chargers, EICRs, central heating refurbs, heat pumps. Variable-rate for diagnostic and repair work, but with hourly rates published on every relevant page so you know before we start.
Can you take a deposit and stage payments?
For jobs over £3,000 we take a 30% deposit at scheduling, 50% on day one, balance on completion. That covers our materials outlay without exposing you. Smaller jobs are paid on completion. We accept bank transfer, card, and Apple/Google Pay; no cash in hand.
Do you offer finance?
Not directly: we're not authorised to broker credit. For boiler installs, Worcester Bosch and Vaillant both run their own finance schemes (0% over 12 months on installs through accredited installers like us). Ask at quote stage and we'll send you the application link.
Do you give written quotes?
Always. Every job over £200 gets a written, itemised, fixed-price quote before any work starts. The quote is yours to keep, valid for 30 days, and the price on it is what you'll pay: line-item breakdown for materials, labour, and any provisional sums.