Boiler Servicing

This e-lesson covers why a boiler requires a service, what is involved in a boiler service and what is different about a boiler service from Craggs Energy.

There are questions after each section so please read the content carefully.

What is an oil boiler?

What is an oil burner?

An oil burner is a heating device which burns heating oil. The fuel is atomised into a fine spray usually by forcing it under pressure through a nozzle which gives the resulting flame a specific flow rate, angle of spray and pattern (variations of a cone shape).

This spray is usually ignited by a spark with the air being forced through around it at the end of a blast tube, by a fan driven by the oil burner motor. The fuel pump is typically driven via a coupling connecting its shaft to that of the motor's. 

How it works...

This is a simple diagram of how the heating system fits together.

Inside a boiler

Why service your boiler?

Oil boiler servicing

Having an oil fired boiler serviced regularly can keep it operating at its most efficient. This reduces fuel bills and saves money on costly call-out fees for unexpected breakdowns. OFTEC recommends that oil fired appliances and equipment are serviced at least once a year or as recommended by the manufacturer.

There are many reasons why the efficiency of an oil fired boiler could be reduced, the next few slides explain how...


Excessive smoke and partially burnt fuel deposits can cause soot to form within the boiler heat exchanger, restricting the amount of heat that can be transferred into the heating system water. The cleaner the heat exchanger, the more efficient the boiler will be.


Oil nozzles regulate how much oil passes through the burner. The nozzles are consumable items that wear over time affecting combustion and lowering boiler efficiency. If they are not replaced, they could cause “sooting up” of the heat exchanger due to too much fuel passing through the burner.


Photocells can glaze over with deposits. Photocells are an important safety feature which detect whether the boiler has lit. If a photocell is dirty it may not be able to detect the burner flame correctly and could cause the boiler to shut down randomly. Boilers frequently switching on and off will be less efficient than those running for longer periods.


Electrodes can wear and attract soot and deposits. Electrodes produce a spark to light the fuel, if they are worn or in poor condition the boiler may not light. Again, causing inconvenience, inefficiency and increasing fuel cost.

The Service

Appliances should be inspected, cleaned and components replaced as required when the boiler is being serviced. If your boiler is not serviced annually, it is at higher risk of breaking down and costing you more money.

Cleaning the boiler provides a chance to look for other tell tale signs that parts of the boiler may need replacing and an opportunity to inspect the combustion chamber for the condition of the material and welds.

Old steel heat exchangers will often leave rust marks, which can give a warning that the boiler will soon need to be replaced. This approach can limit the possibility of water damage occurring and enables replacement work to be planned rather than having the inconvenience of trying to arrange a boiler replacement at short notice when a heat exchanger unexpectedly fails.Long term damage can also occur if the boiler is not serviced regularly.

During the combustion process, deposits will build up on the internal surfaces of the heat exchanger and the baffles which can decrease boiler efficiency. If left for a number of years, these deposits harden and with some designs of heat exchanger render it impossible to remove the baffles without destroying them. A replacement baffle will come at a significant cost on top of the routine service charge.

Carbon Monoxide

As with any fossil fuel burning appliance, poor or inadequate servicing can cause the generation of carbon monoxide. Therefore, it is absolutely vital that your oil boiler is checked and serviced at least annually.

Carbon monoxide is a highly toxic poisonous gas. It is odourless, colourless and tasteless and therefore difficult to detect. Some symptoms of carbon monoxide poisoning are:

  • Tiredness
  • Nausea
  • Headaches
  • Vomiting
  • Dizziness.

It is advisable to fit an audible carbon monoxide detector.

In your own words why should you have your boiler serviced

A Craggs Energy Boiler Service

What is involved?


Please watch this short video to view the boiler servicing process...


The full service

Full oil boiler service

  • Clean the baffles
  • Clean the heat exchanger
  • Clean the oil burner

Genereal checks

  • Check air to fuel mixture
  • Check brass nozzle
  • Check braided hose

Safety checks

  • Carbon Dioxide
  • Nitrous Oxide
  • Carbon Monoxide

Carbon Monoxide

Craggs Energy provide a free Carbon Monoxide detector with every service...

In addition - Craggs Energy provide

  • A detailed report of work undertaken
  • Computer generated report on flue gas readings
  • Detailed OFTEC certified Health check report

We also take pride in leaving the area clean when we leave - as if we were never there!

Fill in the blanks to the following statement...

As part of the oil boiler service, Craggs Energy will check the  nozzle and the  hose. 

In addition to the baffles and oil burner the  will be cleaned.

As well as checking for signs of Carbon Monoxide, Craggs Energy will also check for  and  .

The benefits

The benefits of a boiler service

Saves money on fuel

Cleaning the nozzle, baffles and heat exchangers ensures your boiler runs efficiently and burns all fuel.

Prolongs boiler life

A clean and efficient burn reduces the overall load on the boiler

Keeps you safe

Carbon Monoxide is formed when boilers do not run cleanly

A Free Tank Health Check

Ensuring there are no leaks or vulnerable areas on the fuel tank itself

Match the phases to complete the benefits

  • A free tank health check
    Ensures there are no vulnerable areas or leaks
  • Cleaning the nozzle, baffles and heat exchangers
    Ensures your boiler runs efficiently & burns all fuel
  • A clean and efficient burn
    Prolongs boiler life
  • Prevents carbon monoxide build up
    Keeps you safe

Tank Health Check

Free tank health check

A tank inspection includes

  • Check for leaks, legal conformity, working site gauge and the condition of the tank base.
  • Drainage of tank water separator.
  • Clean tank filter.
  • Check fuel level, water in fuel, sludge in fuel.

FPS video


Examples of tank problems

In your own words, why is it important to check the fuel tank?

Potential Objections

...and how to overcome them

Already had my boiler serviced

Set a call back for when it is due next

My friend services my boiler

Ask if they provide the same level of service as Craggs do

I am on an annual service plan

How much do you pay and what service do you get?

It's too expensive

Emphasise the offering consists of three different services for just £100 plus VAT.

Match the response to the objection...

  • Already had my boiler serviced
    Set a call back for when it is due next
  • My friend services my boiler
    Ask if they provide the same level of service as Craggs do
  • I am on an annual service plan
    How much do you pay and what service do you get?
  • It’s too expensive
    Emphasise the offering consists of three different services for just £100 plus VAT.

Other associated products

Other associated products

Fuel Monitoring

Quickly and remotely view fuel level

Low cost

Can be used as part of a buying plan

Oil fuel tanks

  • Wide range of sizes and capacity available
  • Removal of old tank
  • Provision of tank base

Tank Sponge

  • Removes water from fuel tank
  • Will not soak up oil
  • Easy to install


Please select true or false for the following statements

  • The E-lesson was easy to use
  • The content was at the right level for me
  • The questions were at the right level for me
  • I found this to be an effective way to learn about a new subject
  • I will revisit the E-lesson from time to time as a refresher
  • The training met my personal expectations
  • The E-lesson was interactive