Quick Answer
Every boiler service follows the appliance manufacturer’s instructions, so the exact checklist changes with the make and model. Standard and full are not generic industry definitions. They are the two transparent service tiers we offer at The Happy Heating Co.
Our standard service (£120 fixed) is the annual safety and performance check. A Gas Safe registered engineer tests gas tightness, runs a flue gas analysis, checks controls and system pressure, cleans the condensate trap, tests the expansion vessel, and issues a digital Gas Safe service record. Our comprehensive service (£225 fixed) adds a complete combustion chamber strip-down, heat exchanger wash, genuine replacement burner door seals, and electrode inspection.
Most boilers in good order need only the standard service each year, unless they reach the manufacturer’s five-year gasket renewal interval. We are Gas Safe registered (657972) across West and North West London. See our boiler servicing page.
There is no single industry definition of a “full” boiler service. The phrase means different things at different companies. What follows is what our two levels cover, and how we work out which one a boiler needs.
Key Takeaways
- Most boilers serviced every year need only the standard service (£120 fixed). Age and neglect change the answer.
- On some Worcester boilers, a burner gasket check becomes mandatory once the appliance passes five years (Technical Bulletin TB 0138).
- Replacing a burner gasket restarts that five-year clock and avoids annual sweep testing.
- A boiler with no service history warrants opening up once to establish a reliable baseline.
- Neither service cleans a sludged heating system. That requires a chemical cleanse or powerflush.
Comparing Standard and Full Boiler Servicing
Here is how our two servicing tiers compare side-by-side.
Standard Annual Boiler Service
£120 Fixed PriceBoilers serviced annually, running cleanly without warning symptoms or pressure drops
Flue gas combustion analysis, working gas pressure test, condensate siphon clean, digital Gas Safe record
Visual check; opened only if electronic flue gas readings indicate combustion abnormalities
Approximately 45 to 60 minutes on site (Monday to Friday, 8am to 6pm)
Comprehensive Strip-Down Service
£225 Fixed PriceBoilers unserviced for 2+ years, units over 5 years old, or boilers with ignition hesitation
Full burner strip-down, primary heat exchanger wash, genuine replacement burner door seals, and electrode renewal
Satisfies Worcester Bosch TB 0138 requirements, resetting the 5-year burner gasket interval
Extended 1.5 to 2 hours on-site engineering time
Homeowner Care Plan
£9.99 / MonthAnnual standard service included every year with automated reminder booking
10% discount on all repair labour and diagnostic call-out fees
Priority emergency booking during busy winter cold snaps
Simple monthly direct debit, zero hidden excess fees, and cancel anytime after 12 months
What our standard boiler service includes
This is the annual safety and efficiency check. It follows the manufacturer schedule for your appliance. Our engineers:
- Test gas tightness across the installation to confirm there are no gas leaks.
- Run a flue gas analysis. This measures combustion and confirms the air-gas mixture is correct. A visual check cannot confirm this.
- Inspect the flue terminal and air intake for obstructions.
- Check controls and system water pressure. Older boilers often lack a low-water-pressure sensor. They keep running at zero pressure. This cooks the pump and stresses the heat exchanger.
- Clean the condensate trap. Blocked traps cause winter breakdowns.
- Check and recharge the expansion vessel. Flat vessels cause pressure surges. The relief valve then dumps water outside.
- Issue a digital Gas Safe service certificate on site.
For a boiler serviced annually and running smoothly, this visit is ideal.
What the comprehensive service adds
Everything in the standard service is completed first. Then the combustion chamber comes apart:
- A strip-down and internal clean of the main combustion chamber.
- Burner door seals and casing gaskets replaced with genuine OEM parts.
- Spark and flame rectification electrodes inspected, cleaned or renewed.
The difference is depth. A standard service confirms safety. A comprehensive service renews wear parts and clears internal carbon deposits. For transparent pricing across both service levels, see our boiler service cost guide.
The five-year rule that decides it on some boilers
Here the answer stops being a judgement call.
Worcester Bosch published technical bulletin TB 0138 covering burner gaskets on WB6 appliances. This includes Greenstar 24, 28, 30 FSN GB, and Greenstar Ri, i, Si and i ErP models.
Once a boiler reaches five years old, an extra check on the burner clamp plate gasket is recommended at every service. The check uses a calibrated flue gas analyser around the gasket perimeter.
If any CO or CO2 is detected above ambient levels, the gasket must be replaced immediately. Worcester also recommend cleaning the heat exchanger and replacing the electrodes while the boiler is open.
Replacing the gasket deliberately restarts the five-year clock. It removes the extra check from future annual services.
So which service does your boiler need?
Four key factors guide the decision:
- Unknown service history. Moving into a property in Kensal Rise with no records calls for a comprehensive service. It establishes a clear baseline.
- Age of existing seals. On Worcester and Vaillant models, seals reach their limit at five years.
- Rough combustion symptoms. Boilers struggling to fire or cutting out need an internal clean.
- Preventing future failures. Renewing seals and electrodes before they fail avoids emergency call-outs.
If none of those apply, book the standard £120 service. Save your money.
What neither service fixes
Both levels look after the boiler. Neither service cleans heating pipework.
Cold spots along the bottom of radiators point to magnetite sludge. Slow warm-up times indicate restricted flow. Sludge damages pumps quickly.
Both visits include checking system water and inspecting the magnetic filter. If heavy sludge is confirmed, our central heating services team can recommend a targeted chemical flush or powerflush. Clean water protects boilers.
Frequently asked questions
What is the difference between a standard and full boiler service?
A standard service (£120) checks safety, combustion efficiency, seals, and controls. A full comprehensive service (£225) strips down the combustion chamber, cleans the main heat exchanger, and replaces burner door seals and electrodes.
How often should a boiler have a comprehensive service?
Most boilers need a comprehensive strip-down every 4 to 5 years, or whenever burner door gaskets reach their manufacturer replacement interval (such as Worcester TB 0138).
How much does a standard boiler service cost?
Our standard weekday service is a fixed £120 across West London. Our comprehensive strip-down service is a fixed £225.
Can landlords book a service and CP12 together?
Yes. Landlords frequently combine an annual boiler service with their statutory CP12 gas safety check (£79 fixed for 1 appliance + £35 for additional appliances).
Does annual servicing keep my warranty valid?
Yes. Worcester Bosch, Vaillant, Ideal, and Baxi make annual servicing by a Gas Safe registered engineer a mandatory warranty condition.
Book the right service for your boiler
Tell us your boiler make, age, and service history. We will give you a straight answer on which service tier is right for your home.
- WhatsApp us: Book in 60 seconds
- Call 020 8051 2124: our phone line is answered 24/7
- Book online: boiler servicing · Homeowner Plan
We are Gas Safe registered (657972) and service boilers across West and North West London. Heating that just works, no drama.
Book Your Annual Boiler Service in West London
Our Gas Safe registered engineers (657972) offer standard maintenance services (£120) and full strip-down clean services (£225) across West and North West London.
