Boiler Servicing.

Many people are a bit puzzled by boiler servicing. Puzzled about what it is, why it should be done, and what happens if it is not carried out regularly.


A boiler service is checking, cleaning, testing and pre-emptive fault-spotting, really, with the emphasis on testing all the different functions of an appliance for correct and safe operation.


VERY IMPORTANT - You must use a flue gas analyser to service modern boilers. Always check to see if the engineer has one, like the one pictured here.

Unfortunately, different companies have widely differing ideas about what should be done to service a boiler. At one extreme some (bigger) companies have their engineers do no more than put a probe in the flue outlet to analyse the contents of the flue gasses, and if all is well, announce the boiler is working correctly and start writing out the invoice. Beware these companies. Their short-cutting can often be spotted by looking carefully at the wording of their offering. When you ask for a "boiler service" you will be offered an "annual safety check" instead, misleading you into thinking you are getting a full annual service.


At the other extreme there are gas installers who check the gas pipework, ventilation, clearances etc then take everything to pieces, clean and reassemble, and spend ages testing the operation of every single aspect of the boiler functions for safe and correct operation.


When a boiler or gas appliance appears to be working well, there 'could' be hidden faults. These will be revealed by a proper service. A good example would be the device which turns the gas off if the pilot light blows out or the flame failure device on more modern boilers fail. If this fails to work when needed you could have gas leaking into your house, but how do you know if yours still works? This will be tested during the service procedure. Click here for the full service procedure, if you want to know in complete detail what a proper service comprises.


What happens if not carried out regularly...Well, in most cases, everything will be fine, but you won't know for sure. The whole gas installation is examined and tested for correct installation and operation. A wide variety of things go wrong with gas installations and the gas regulations exist to make sure installations are safe. Proper servicing, in summary, makes sure your installation is safe.


Never try to service or repair your boiler yourself. If you are a tenant in rented accommodation, your landlord is responsible for ensuring your system is serviced regularly and kept in good condition. Always contact your landlord if you have any concerns regarding this.


Gas appliances that are not well maintained are at risk of giving off carbon monoxide, which is a potentially fatal colourless and odourless gas. Gas fires are particularly at risk of this, so regular checks are a must. A carbon monoxide detector can be fitted in your home, which will warn you of any presence of the gas. These are inexpensive to buy and can be purchased from electrical or DIY stores.


How often should servicing be done?

Most manufacturers recommend annually as does the GAS SAFE Register (The New Corgi Body) . If you own an open flued appliance its very important to have it serviced annually (vertical, chimney-style) rather than a balanced/fan flue (horizontally, through the wall).


Open flued appliances can cause carbon monoxide deaths quite easily. It is so easy for combustion products to get into the house when something goes wrong with the flue (or the ventilation), and frequent servicing helps identify flueing problems early.


Balanced flue and fan flued appliances are less critical. Manufacturers still say once a year mainly because flue problems are rarer and usually less serious, though still happen. And also because they draw clean fresh air from outside. This means the burner airways don't get accumulations of carpet fibres, pet hairs etc (called 'lint' in the trade) in them.


The government has issued safety guidelines regarding gas appliances, which should be adhered to at all times.

  • Do not attempt to use any gas appliance that you think may be faulty. Warning signs can include flames that are yellow or orange (if they aren't intended to be this colour), stained or sooty appliances and pilot lights which frequently go out.
  • Do not block air vents on appliances or cover the appliance in any way.
  • Do not obstruct or block airbricks or ventilation grilles.
  • Do not cover or block flues.