In depth
Materials, methods and variations.
A boiler service isn't one job — it's six. Visual, mechanical, combustion, gas, safety and documentation. Skip any of them and it's not really a service. Here's what shapes a proper visit on the brands we see most often in Coventry housing.
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Service depth by brand
Worcester Bosch Greenstar: annual full service required for the 8/10-year warranty — burner inspection, condensate trap clean, combustion analysis logged. Vaillant ecoTEC: similar schedule, with particular attention to the ignition electrode and flame sensor. Ideal Logic Max / Vogue Max: 10-year warranty conditional on annual service, with documented Adey MagnaClean filter clean. Baxi 800 / Platinum: 10-year warranty conditional on annual service plus magnetic filter. We follow each manufacturer's published service schedule line-by-line, not a one-size-fits-all checklist.
Combustion analysis explained
Calibrated combustion analyser on the flue test point. Healthy combustion shows CO under 100 ppm, CO2 between 8% and 10% (model-dependent), CO/CO2 ratio under 0.004 and oxygen between 4% and 7%. Anything outside those bands gets investigated — burner soot, blocked condensate, flue terminal damage, gas pressure deviation, incorrect air/gas ratio. We don't just read the numbers; we act on them.
Landlord CP12 certificates
Gas Safety Certificates (CP12) are a legal requirement on all rented residential property in England under the Gas Safety (Installation and Use) Regulations 1998. Every gas appliance — boiler, gas fire, gas cooker — must be inspected annually and a certificate issued. Tenants must receive a copy within 28 days of the inspection (or before move-in for new tenancies). We can typically issue same-day where the system passes.
Older non-condensing boilers
Boilers over 15 years old (typically pre-2005 non-condensing models) still get serviced properly — we don't refuse work on an older boiler. But we'll always flag the running cost differential vs a new A-rated condensing boiler honestly, with rough numbers. No pressure to replace; just enough information to make the next decision when you're ready.
What's not included as standard
Power flushing (separate service, only needed when system condition warrants it). New parts (quoted separately at service if found). Magnetic filter installation (recommended on any system without one; quoted at service). Repairs to flue or external pipework. We'll never bundle these into the service price without telling you exactly what and why.
Residential vs commercial
Domestic gas boilers up to 70kW covered routinely under our standard ACS competencies. Commercial gas boilers (over 70kW or in commercial premises) require additional COMCAT qualifications and we'll refer you to a trusted commercial gas engineer where the job exceeds that scope. We won't take work we're not qualified for.