Combi Boiler Servicingin Hazel Grove & StockportDone to Manufacturer Spec.
Combis are compact, complex and worked hard, heating your radiators and your hot water on demand. An annual specialist service keeps efficiency high, warranty intact, and the plate heat exchanger out of the skip.
Combi Boiler Servicing, done properly.
Combi boilers do two jobs at once: run your central heating and heat your hot water instantly. That combined workload is exactly why they need attention every year. A combi that isn't serviced properly is a combi that starts to lose flow rate on the taps, drop pressure overnight, and eventually chew through a plate heat exchanger long before it should.
A combi service covers the same core work as any boiler service, casing off, combustion chamber cleaned, flue gas analysis, gas pressure verified, plus the combi-specific checks: expansion vessel pre-charge, secondary heat exchanger flow rate, diverter valve operation, and system pressure loss patterns.
Anyone with a wall-hung combi boiler in a house, flat or terrace. Around 80% of properties in Hazel Grove and the surrounding streets run a combi, and every one of them benefits from being looked after by someone who works on that make daily.
Annually, on the anniversary of installation or the previous service. If you've noticed hot water going lukewarm mid-shower, radiators taking longer to heat, or the pressure gauge dropping without an obvious leak, bring the service forward and we can diagnose it in the same visit.
Combis are unforgiving. Small problems compound: scale narrows a plate heat exchanger by a fraction each year, expansion vessels lose pre-charge, and the diverter valve sticks. Left un-serviced, that's a £400–£700 repair. Caught at service, it's a five-minute adjustment or a modest part.
Real jobs, real results.
Photographs from recent combi boiler servicing work carried out by John across Stockport and the surrounding areas.
The cost of putting it off.
Combis fail in predictable ways when they're not looked after. Every one of the problems below is one we regularly correct in properties that had 'a service last year' from someone who didn't actually open the boiler.
Falling hot water flow rate
Scale silently coats the plate heat exchanger, hot water takes longer, and the shower drops from strong to disappointing. Left long enough, the exchanger is a full replacement.
Overnight pressure loss
A tired expansion vessel or leaking auto air vent shows up as pressure that drops every few days. Un-diagnosed, it eventually locks the boiler out completely.
Sticking diverter valve
The valve that switches between heating and hot water sticks. You get heating but lukewarm water, or hot water but no heating. Common. Preventable at service.
Voided warranty
Every major brand, Worcester Bosch, Vaillant, Ideal, Baxi, requires an annual service. Skip it and the free repair becomes a paid one.
- Booking the cheapest combi service you can find and not checking whether a flue gas analyser was actually used.
- Ignoring gradual hot water performance loss because it 'still works'.
- Topping the boiler pressure up week after week rather than getting the underlying leak or expansion vessel diagnosed.
A clear five-step system.
No guessing, no meter-running. Every job follows the same repeatable process, that's how the result stays consistent.
- 01
System check
System pressure, expansion vessel pre-charge and pump operation confirmed before we open the casing.
- 02
Combustion strip-down
Burner, heat exchanger and injectors cleaned. Combustion chamber inspected for scoring or scale.
- 03
Flue gas analysis
Analyser readings taken at low and high fire, the only accurate way to confirm a combi is burning cleanly.
- 04
Water-side checks
Diverter valve tested, plate heat exchanger flow rate assessed, sensors verified against manufacturer values.
- 05
Sign-off & report
Full written record, workmanship guarantee, and a plain-English summary of anything to keep an eye on.
What you actually get.
Full-strength showers
Keeping the plate heat exchanger clean protects hot water flow rate long-term.
Stable pressure
A properly re-pressurised expansion vessel stops the weekly top-up cycle.
Warranty protected
Annual service logged means the manufacturer can't decline a claim on a technicality.
Efficient gas burn
Combustion-tested boilers hit their SEDBUK efficiency band; neglected ones don't.
Fewer winter no-heats
The mid-January breakdown is almost always something a summer service caught early.
One engineer, every time
The same person services your boiler, remembers its quirks, and returns if it ever fails.
The detail that matters.
Combi boilers all share the same DNA but each brand has its own service quirks. Servicing without brand-specific knowledge is why so many combis get a 'service' one year and a breakdown call-out the next.
Worcester Bosch
Greenstar 30i, 4000, and 8000-series combis all covered. Common service points: expansion vessel pre-charge, condensate trap flush, plate heat exchanger inspection. Genuine Worcester parts fitted where required for warranty compliance.
Vaillant ecoTEC
ecoTEC Plus and ecoTEC Pro models covered. Frequent service issues include diverter valve wear, pressure sensor drift, and expansion vessel pre-charge loss, all addressed at annual service.
Ideal, Baxi & Glow-worm
Ideal Logic and Vogue, Baxi 800/600, Glow-worm Energy and Ultimate, all serviced to manufacturer schedule. Particular attention to Ideal's condensate traps and Baxi's fan assemblies, which are common wear points.
Old vs new combis
Pre-2005 combis (non-condensing) are still supported and serviced honestly, if a part is unavailable or the repair isn't economical, we tell you before we start rather than after we've invoiced.
Questions we hear every week.
If you have a question that isn't answered here, ring John directly on 07442 536165.
Often booked together.
Combi due a proper service? Book John directly.
Manufacturer-spec service, genuine parts where required, and the same engineer every time.