A boiler service is a set of measurements, not a look at the casing. This page sets out what gets checked, how long it takes, and what you are left with afterwards. Call 01462 506 374 and speak to a Gas Safe registered engineer.

What a boiler service actually includes

A service is a sequence of checks and recorded readings. On every service we carry out:

• A flue gas analysis, recording combustion ratio and carbon monoxide output against the manufacturer figures for that appliance
• Removal of the casing to inspect the burner, heat exchanger and injectors
• A check of the seals and the combustion case for integrity
• Gas rate and operating pressure measured at the appliance and compared with the data badge
• A flue integrity check, including the terminal and its clearances
• Condensate trap and pipework checked and cleared
• Safety devices tested, including the overheat thermostat and the flame supervision device
• System pressure and expansion vessel charge checked
• A visual check of ventilation to the appliance where it is required

If any reading falls outside the manufacturer tolerance we tell you what it is, what it means, and what the options are before doing anything else.

The paperwork you should be given

At the end of a service you should receive a record showing the appliance make and model, the readings taken, any defects found, and the engineer Gas Safe registration number. Ours is 956889. If a service does not produce a document with numbers on it, it was not a service.

Keep the record. Manufacturers ask for it when a warranty claim is made, and buyers ask for it when a house is sold.

Why servicing matters more in Letchworth than elsewhere

This is the part that changes what we recommend. Affinity Water measures the supply into Letchworth at 318 mg/l of calcium carbonate, which is very hard on their own scale. Scale forms on the hottest surface in the appliance, so in a combi it collects on the plate heat exchanger and in a system boiler on the primary exchanger.

That figure is why a service here is worth more than a box ticked, and it is why on a Letchworth property we will usually recommend a magnetic filter and tell you whether treating the incoming water is worth it. On a soft water supply that advice would be padding. Here it is the difference between a heat exchanger lasting its design life and failing early, and it is what keeps a manufacturer warranty defensible.

The early signs are a hot tap that runs hot then lukewarm, a boiler that kettles on start-up, and hot water taking longer to arrive.

How long a service takes

A straightforward service on an accessible boiler in good condition is usually completed in a single visit. How long it takes depends on the appliance, where it is fitted, and what the readings show. A boiler in a first floor airing cupboard with a clear front is quicker than one boxed into a fitted kitchen behind a removable panel.

We do not book services in a way that means rushing the checks. If a reading is wrong, the time it takes to find out why is part of the job.

When your boiler should be serviced

Annually is the standard interval and it is what almost every manufacturer requires to keep a warranty valid. The month matters less than the consistency. Servicing in late summer or early autumn means a fault is found before the heating is needed rather than during the first cold week, which is when every heating engineer in Hertfordshire is busiest.

Servicing and your manufacturer warranty

Worcester Bosch, Vaillant, Ideal, Baxi, Glow-worm and Viessmann all require an annual service by a Gas Safe registered engineer, recorded, to keep their warranty in force. A missed year can invalidate cover that still had several years to run.

A service is not a landlord gas safety check

The two are different jobs and are often confused. A landlord gas safety check, the CP12, is a legal safety inspection of the gas appliances, pipework and flues in a rented property. It confirms the appliance is safe. It does not include cleaning the burner, checking the heat exchanger condition, or the maintenance work that keeps the boiler running well.

A service and a safety check can be carried out on the same visit, and for a rental property that is usually the sensible arrangement. Paying for a CP12 and assuming the boiler has been serviced is a common and expensive mistake.

Signs your boiler is overdue

• Banging, kettling or whistling when the heating fires up
• Hot water that runs hot, then cools, then recovers
• The boiler locking out and needing a reset more than very occasionally
• Pressure dropping and needing topping up regularly
• Radiators taking noticeably longer to warm than they used to
• A yellow rather than crisp blue flame on an appliance where the flame is visible
• Any staining or sooting around the case

Any staining, sooting or a yellow flame should be treated as urgent rather than as a servicing matter.

Which boilers we service

Combi, system and regular boilers from Worcester Bosch, Vaillant, Ideal, Baxi, Glow-worm, Viessmann, Potterton, Ferroli, Alpha, Main and Ariston. Our vans carry the common service parts, so the majority of routine work is finished on the first visit.

What happens if we find a fault

We tell you what the reading was, what it should have been, and what is causing the difference. Then you get a fixed price for the repair before any further work begins. If the honest answer is that the appliance is at the end of its economic life, we will say so rather than sell you a repair that buys a few months.

Where we service boilers around Letchworth

Across the SG6 postcode. Letchworth was the world’s first Garden City, founded in 1903, and much of the original Arts and Crafts housing is still in use. Those houses were not designed around modern heating, so boilers end up in converted pantries, under stairs and in outbuildings, and flue routes have to work around fabric that is often protected. A good many properties in the estate also sit under Heritage Foundation covenants, which is worth knowing before anyone starts talking about a new external flue terminal.

Why the engineer must be Gas Safe registered

It is a legal requirement for anyone working on a gas appliance in the United Kingdom. Every Vantage engineer is registered, and you are entitled to ask to see the card before work starts. Our registration number is 956889 and it can be checked on the Gas Safe Register. Vantage Plumbing and Heating is a limited company, number 13248357.

Book a boiler service in Letchworth

Call 01462 506 374 and speak to an engineer. Every job carries a two year guarantee on our own labour.

Frequently asked questions

How often does a boiler need servicing? Once a year is the standard interval and it is what manufacturers require to keep a warranty valid.

Does a service include a magnetic filter clean? If a filter is fitted we will check and clean it as part of the visit. If one is not fitted we will tell you whether it is worth adding, which in Letchworth it usually is.

Will servicing stop limescale? No. Servicing finds scale early and keeps the appliance running properly, but the only way to reduce scale forming is to treat the water going in.

Can you service a boiler somebody else installed? Yes. We service appliances regardless of who fitted them.

What if my boiler fails the service? We explain what failed and why, give you a fixed price to put it right, and if it is unsafe we will make it safe and tell you plainly what that means.

Related: boiler servicing across Hertfordshire, boiler installation in Letchworth, power flushing in Letchworth, plumbers in Letchworth and all our services in Letchworth.