Diagnostic + minor fix
Quoted
Most repairs fixed in the first visit
- Full diagnostic procedure
- Common spares from the van (PCBs, fans, igniters)
- Same-visit fix on 70% of calls
- Flue gas analyser readings
- 12-month warranty on the fix
Boilers
Boiler repair & servicing
Same-day repairs, annual services, and landlord gas safety certificates. Most boilers fixed first visit, most parts on the van.
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.
What's going wrong?
Find the closest match. Phone is fastest, and Nigel will usually tell you the next step on the call.
- No heating but hot water
Usually a diverter valve or motorised valve fault. Most common winter callout. Diagnostic + part bench-priced from £200.
- No hot water but heating works
Diverter valve stuck the other way
- Pressure keeps dropping
External or internal leak
- Boiler leaking from underneath
Often a pump seal
- Error code on the display
Send a WhatsApp photo of the code. Most are diagnosable before we leave the van.
- Pilot or ignition fault
Modern combis are flame-rectification
- Radiators cold at the bottom
Usually sludge
- Boiler making banging or kettling noises
Limescale on the heat exchanger or a sticky pump. Treatable
Indicative scope
Exact pricing is confirmed before work starts and depends on the property, access, parts and fault diagnosis.
Major repair
Quoted
Heat exchanger, pump, diverter valve replacement
- Common heat-exchanger faults
- Pump replacements (Wilo / Grundfos)
- Diverter valve / 3-way valve
- PCB or display replacement
- Worcester / Vaillant warranty preserved
Service plan member
Quoted
Priority response + 10% off labour
- Annual service included
- Priority callout (4 hours working hours)
- 10% off all repair labour
- 5% off any new install
- No chase-the-calendar reminders
Repair & service
No heat, hot water, or pressure?
Same-day repairs, annual services, and landlord gas safety certificates. Most boilers fixed first visit, most parts on the van.
Most boiler problems aren’t catastrophic: they’re a worn part, a clogged filter, a failed sensor, or a system that hasn’t had a proper look-over in five years. We diagnose, quote, and fix in one visit where we possibly can. From £90 first hour with most parts on the van.
Same-day repairs
We carry stock for the most common Worcester, Vaillant, Viessmann, and Ideal parts on the van. 70% of repairs are completed on the first visit. Common parts on board:
- PCBs / control boards: Worcester Greenstar i and Vaillant ecoTEC are the most common (90% of UK boiler PCB failures sit between these two).
- Fan assemblies, particularly Worcester Heatslave and Vaillant ecoTEC.
- Diverter / 3-way valves: most common Worcester, Vaillant, Ideal codes carried.
- Pressure sensors, Worcester low-pressure switches and Vaillant pressure transducers.
- Pumps: Wilo Yonos, Grundfos UPM3 (used in 80% of UK domestic boilers).
- Igniters and electrodes, universal-fit options for most condensing boilers.
- Expansion vessels: replacement diaphragms or full units.
- Condensate trap units (Worcester, Vaillant, Ideal common patterns).
For less common parts (or premium models like Viessmann Vitodens 200, Buderus, Atag), the parts run is usually 24–48 hours. We’ll tell you the timeline and the cost up front.
Common faults we diagnose
- No heat but hot water OK: usually diverter valve. £200–£280 fitted.
- No hot water but heat OK, usually diverter or DHW heat exchanger. £200–£480 fitted depending on model.
- Boiler losing pressure: failed expansion vessel pre-charge, leak in heating circuit, or failed PRV. £90–£280 depending on cause.
- Boiler displays fault code. Worcester EA, Vaillant F75, Ideal C2 and others each have a known cause, and we arrive with the likely parts.
- Boiler keeps locking out, usually a sensor (flame, pressure, temperature) or a corroded electrode. Usually diagnosed in the first 30 minutes on site.
- Kettling noises: usually scaled-up heat exchanger or sludgy system. May need powerflush and possibly a heat exchanger swap.
- Boiler short-cycles, typically over-sized boiler for the system, sludge, or under-sized rads. Diagnose, quote remediation.
Pricing
| What | Price |
|---|---|
| First-hour diagnostic + minor fix | £90 |
| Subsequent hours | £55/hour |
| Common parts (PCB, fan, sensor) | £200–£480 fitted |
| Major heat exchanger swap | £480–£900 fitted |
| Annual service plan | £12.50/month |
The annual service plan is genuinely good value if you’d rather not deal with calendar reminders or sudden repair bills:
- Annual service included (worth £90).
- Priority callout within 4 hours during working hours.
- 10% off all repair labour outside the service visit.
- 5% off any new install / cylinder swap.
- No chasing the calendar: we book the schedule.
Effective annual cost is ~£150 with the service included; spreads across 12 months.
Annual servicing
A full boiler service includes the safety inspection, all the manufacturer-required cleaning, a flue gas analysis, and a written certificate at the end. Annual servicing is what keeps manufacturer warranties valid; skipping it usually voids them. £90 for a combi service, same-week booking, certificate within 24 hours.
Landlord gas safety certificates (CP12)
We issue full CP12 certificates for landlords across Cardiff and South Wales. We can work directly with your tenants to arrange access. £75 per property for a single appliance; quoted for portfolios. See CP12 page for full pricing and how the tenant scheduling works.
Common mistakes other firms make
- Replacing the PCB without diagnosing the cause. A PCB can fail because the PCB itself is end-of-life, or because a flame sensor is faulty and the PCB has tripped a fault. Replacing the PCB without checking the sensor means another PCB failure in 6 months.
- Skipping the flue gas analyser reading after a repair. A repair that hasn’t been combustion-tested is half-done. Every repair we make ends with a full FGA reading recorded on the receipt.
- Recommending a new boiler when a £180 repair will fix it. Particularly common with PCB and pump failures on 5–10 year old boilers. Always get a second opinion if a “boiler is dead” diagnosis comes after 5 minutes of looking.
Workmanship and warranty
12-month repair warranty. If the same fault recurs, the return visit is free. Manufacturer warranties on replacement parts typically 2 years (Worcester, Vaillant, Ideal). Every repair registered through the manufacturer portal so warranty cover is preserved on the boiler itself.
★★★★★
Provided a full service for our boiler. Fantastic communication from the beginning. No hidden costs. Efficient and friendly service. Reliable, professional and trustworthy.
Recent jobs near you
A few of the jobs we have finished lately, with the postcode and what was involved.
- CF5 April
Llandaff: Worcester Greenstar PCB failure, fixed first visit.
- CF24 April
Roath, Vaillant ecoTEC pressure sensor + repressurisation.
- CF14 March
Whitchurch: Ideal Logic fan replacement.
- CF11 March
Pontcanna flat, Viessmann diverter valve, hot but no heat.
- CF64 March
Penarth: Worcester combi expansion vessel pre-charge restore.
How the job runs
- 01
Photo + symptom
2 minPhoto of the boiler and the fault code if it shows one. We'll quote a likely band before the visit and bring the right parts.
- 02
Diagnostic
30–60 minFirst hour is the diagnostic. We carry a Worcester / Vaillant / Viessmann fault-code reader for the common modern boilers and replicate the fault to find the actual cause.
- 03
Fix
Within visit70% of repairs are completed in the first visit. Common parts (PCBs, fans, igniters, pressure sensors, diverter valves, pumps, expansion vessels) carried on the van.
- 04
Pressure-test + commission
20 minBoiler refilled, pressure-tested, full flue gas analyser reading taken. Combustion ratio, working pressure, water flow all recorded.
- 05
Aftercare
12 months12-month warranty on the repair. If the same fault recurs, return visit free. Manufacturer warranty preserved through registered service.
Common questions
What counts as an emergency?
Suspected gas leak (call us first, then turn off at the meter). No heat or hot water in winter where there are kids, elderly residents or vulnerable people. Burst pipes, meaning water actively coming through ceilings or walls. Sewage backing up. Anything actively damaging your house or making it unsafe.
How fast will you get there?
Inside Cardiff, 60 minutes door-to-door for genuine emergencies. Penarth, Llandough, Roath: 60–75 minutes. Barry, Caerphilly, Cowbridge: 60–90 minutes depending on the time of day. We'll give you the live ETA when we pick up.
What does an out-of-hours callout cost?
Standard out-of-hours rate is £150 for the first hour (covers diagnosis and most fixes), £85 per hour after. Materials at trade plus 15%. Bank holiday rate is £180 first hour. Genuinely-urgent cases involving vulnerable residents we'll discuss the rate before we set off.
Do you actually answer the phone at 2am?
Yes, between 7am and 7pm Nigel or one of our engineers picks up directly. Outside those hours, your call goes through a triage line that makes a real-time decision. True emergencies wake Nigel within minutes. Things that can wait until morning, we take details and call back at 7am. You always get a same-day human reply.
My boiler's lost pressure overnight, is that an emergency?
Usually not. Re-pressurise via the filling loop (target 1.0–1.5 bar cold) and we'll come out on a normal callout slot tomorrow. If it keeps dropping there's a leak somewhere; that's worth a same-day visit. If you've got no heat and someone vulnerable in the house, it's an emergency and we'll come out tonight.
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.
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.