Mandatory Gas Appliance Checks! What Should Your Gas Engineer Be Checking?

09 May. 2019

Written by Neil Marsh MCIPHE RP RHP EngTech

When a gas engineer WORKS on a gas appliance, they must undertake mandatory checks to ensure the safe operation of the gas appliance. The engineer, where ever reasonably practicable, must ensure that all these checks are undertaken every time the appliance is worked on… Some circumstances out of the engineer’s control may prevent certain checks from being done, which in some instances may be able to be passed as “UNABLE TO CHECK”. However, safety must not be compromised! Where safety may be a concern, the responsible user of the appliance (owner/tenant) may be advised of the DANGEROUS SITUATION PROCEDURE which could lead to an AT RISK or IMMEDIATELY DANGEROUS notice being issued. This could lead to the gas appliance being isolated or disconnected from the gas supply.

The Gas Safety (Installation & Use) Regulations of 1998 specify that “work” in relation to a gas fitting relates to the following:

  • Installing or reconnecting the fitting.
  • Maintaining, servicing, permanently adjusting, disconnecting, repairing, altering or renewing the fitting, including purging it of gas.
  • Moving the fitting.
  • Removing the fitting.
  • They also specify that gas fittings are defined as: Gas pipework, valves (other than emergency controls), regulators, meters, fittings, apparatus, and appliances designed for use by consumers of gas for heating, lighting, cooking or other purposes for which gas can be used (other than the purpose of an industrial process carried out on industrial premises). This does exclude storage vessels and such things as the service pipe.

So What Is Considered As Working On A Gas Appliance:

In regards to gas appliances, “work” is any duty undertaken on the appliance that the user would not be expected to do, for instance, adjusting the user controls or topping up water pressure on a gas appliance would not be deemed as working on a gas appliance as those operations are listed in the manufactures instructions as operations to be undertaken by the user.

If a gas engineer undertook such an action on a gas appliance, they still must complete a visual inspection of the appliance. If anything potentially dangerous (AT RISK or suspects IMMEDIATELY DANGEROUS) is identified, then the engineer must work on the appliance and conduct all of the mandatory checks to fully clarify the correct potential of threat and take the appropriate actions.

An example of a situation like this is where an engineer attends a property and is presented with an open flued gas boiler (takes air from the room to feed the combustion process), The engineer notices that the pilot light has gone out, and the engineer corrects the issue by relighting the pilot light (which is a user operation). However, while conducting visual checks, they identify that the vent that supplies air for combustion (that comes into the room from outside or a series vents to outside) is undersized by more than 10%, which would be classed as an AT RISK situation. The engineer now must prove that the inadequate supply of combustible air is not having a detrimental effect on the safe workings of the boiler, they must work on the boiler and conduct all the mandatory checks to ensure the boiler’s safety.

Were a boiler shows no signs of an immediate threat but could cause harm to life or damage to property in the future, the classification will likely be AT RISK. However, if anything dangerous is found, the appliance will be classed as IMMEDIATELY DANGEROUS.

Gas Engineers Have Legal Obligations To Appliances And Installations They See:

When a gas engineer is working in a property, they are required to visually inspect every gas appliance they walk past in the course of their duty. Should work be undertaken that would interrupt the supply of gas in the property, the gas engineer must visually inspect every appliance connected to that supply and check the safety (work on) any appliances they suspect to be dangerous.

The Tests Performed Vary:

Some of the mandatory checks will vary slightly depending on the situation, such things as gas type being used, the type of appliance and flue will affect what checks are undertaken and how they are completed. The principles of combustion apply across all gas appliances, generally, the key fundamental checks are the same.

The Recording Of Information:

Gas engineers should be recording their findings on a job sheet. However, this is not mandatory and is considered good practice. Where certification (landlord gas safety certificates, appliance commissioning etc) is required, or dangerous situations are identified, documentation must be issued to the gas user and/or landlord. Some companies use electronic devices to retain job sheet information, which is acceptable, but any data that is held about you, you are entitled to request should they not issue paper job sheets.

They must always issue paperwork for unsafe situations (AT RISK & IMMEDIATELY DANGEROUS) and where aspects of a gas appliance/installation do not comply with the current standards in place they are to issue in writing a NOT TO CURRENT STANDARDS advice for any flue or ventilation issues and advise you verbally (although written is recommended) in all other NOT TO CURRENT STANDARD situations.  

Legislation dictates that when a gas engineer works on a gas appliance they must:

Be competent to do so (skill, knowledge, understanding) and have the relevant qualifications.

Comply with the manufactures instructions (installed correctly).

Fully comply with the Gas Safety (Installation & Use) Regulations, British Standards, Building Regulations, Electrical Regulations and other such legislation that may be relevant to what they are doing.

Examine the effectiveness of any flue, the supply of combustible air, its operating pressure and/or heat input and ensure it is functioning safely.

Emphasis must be put on ensuring a gas appliance is functioning safely, although this is a small statement, it includes many areas of an appliance that needs to be checked. When an engineer undertakes work on a gas appliance, they must check the following:

The gas rate and/or burner pressure of the appliance. Gas rates should be no more than 5% over the specified amount on the data badge or 10% under. Burner pressures should be checked and set suitably (where applicable) in line with the manufactures instructions.

The ventilation to the appliance. Undersized ventilation (by 10% or more) for the supply of combustible air is to be classed as AT RISK unless other factors make the situation IMMEDIATELY dangerous.

The flue/chimney system along its full length. Flues that are not accessible for inspection (with exception to certain clauses) should be classed as AT RISK unless other factors lead to the situation being IMMEDIATELY DANGEROUS.

Flue flow & spillage checks. These tests are undertaken on open flued appliances to determine that flue performance is adequate for the appliance. Should any of these checks fail then the situation is to be classed as IMMEDIATELY DANGEROUS.

Flue gas analysis (FGA). These tests are mandatory on certain appliances but not all. It is strongly advised that where ever possible an FGA test is undertaken. Poor readings could lead to an AT RISK or IMMEDIATELY situation depending on the severity and any appliance that it is mandatory to conduct an FGA test upon where it is not possible to do so will be classed as IMMEDIATELY DANGEROUS.

Safety device operation. This is any device that is responsible for ensuring the appliances safe operation, predominantly engineers may refer this test to the flame failure mechanism, however, safety limit stats, proofing switches, and similar devices can be classed as safety devices. These devices should be checked to ensure that they are in good working order, depending on the component the devices may be classed as controls. A defective safety device is to be classed as IMMEDIATELY dangerous.

The burner. The burner should be visually inspected for defects and to ensure that it is clean. Some appliances have other tests that can be undertaken to avoid removing the burner for inspection so long as the readings are within a set range. A defective burner is to be classed as IMMEDIATELY dangerous.

Controls. Any control that compromises the safe working order of the appliance is likely to be classed as IMMEDIATELY dangerous. A failed control that is preventing the appliance from working could be categorised as AT RISK where the gas appliances safe operation could not be confirmed due to the appliance being non operational. Categorising an appliance AT RISK when it is non-operational is good practice and advised, especially where faults are intermittent. 

The ignition sequence & flame picture. Should be inspected to ensure the boiler is igniting and burning in a safe manner, issues with the ignition process or flame picture can indicate issues elsewhere with the appliance that could lead to being classed as AT RISK or IMMEDIATELY dangerous.

The heat exchanger (if applicable). To ensure it is clean and free from defect. A faulty heat exchanger could lead to a boiler being classed as AT RISK or IMMEDIATELY dangerous.

The wiring/electronics (if applicable). Should be checked to ensure they do not compromise the safety of the appliance, again depending on the extent of the issue this could be classed as AT RISK or IMMEDIATELY dangerous.

Seals (if applicable) are intact and in good order. Seals that have failed that are responsible for ensuring gas tightness, the safe operation, such as sealing the products of combustion from the room, are to be classed as IMMEDIATELY DANGEROUS.

The appliance is stable. Unstable appliances will be classified as either AT RISK or IMMEDIATELY dangerous depending on the severity of the situation.

With gas fires other such checks like catchment space (the space behind or what the fire sits in), the surround/hearth coal beds/radiants are to be checked also classification will vary depending on the situation.

Anything else that could affect the safety of the appliance.

As you can see, several checks that are required and the time required to undertake all these checks will depend on the gas appliance. These checks cannot be completed in just a few minutes. This should arouse concern towards gas engineers that are working on gas appliances for brief periods of time and/or only using limited amounts of tools.

Poor Workmanship:

Sadly, in FORTHRIGHT’s experience as we have operated around Cheltenham, Gloucester and the surrounding areas of Gloucestershire, we have had many reports and witnessed first hand situations that would suggest that not all gas engineers are following the set procedures that are in place to ensure gas appliances such as boilers, fires, cookers and hobs are working safely.

For those concerned about recent and past boiler services, click here to find out what a correctly undertake boiler service should include.

Excising Judgement

Gas engineers should always exercise their judgement when classifying the safety of a gas appliance. It is seen to be of good practice to edge on the side of caution. This does not mean that an engineer should be over classifying every situation as this is not practical or reasonable, however, in some instances the engineer’s discretion may increase or decrease the level of the classification which the engineer exercises. So long as the engineer is practicably reasonable, they may adjust classifications as they see fit and exercise their judgement as situations can vary. Code of Practice is in place to help engineers handle different situations, however ultimately responsibility will always fall on the engineer.

Keep Your Gas Appliance Installation Instructions!

Keeping manufactures instructions for your gas appliance accessible for the use of gas engineers is important. Appliances that the gas engineer frequently works on will often be able to be serviced without manufactures instructions, as the engineer may have substantial experience with that particular appliance. However, if the engineer is unfamiliar, or cannot remember key aspects about the appliance, they may need to refer to technical specifications in the instructions (or seek advice from the manufacturer) to aid in the work that they undertake on the appliance. 

Do not be concerned if a gas engineer asks you for the manufactures instructions. It is likely that the engineer is taking great diligence while working on your appliance. If an engineer cannot clarify information and is unsure of the safety of the appliance, you could be issued with an AT RISK warning notice.

Unsafe Situations Procedure

If a gas appliance is classified as AT RISK then you should be notified in writing of the reason why. A warning label should be attached to the appliance and the gas engineer should advise you that they have a legal duty of care to advise you not to use the appliance and explain all the associated risks in doing so. They should then seek your consent to turn off the appliance in writing, isolate the appliance from the supply of gas and make safe.

Where you refuse to have the appliance made safe, the engineer should request that you acknowledge that they have advised you of the risks associated with the appliance by signing a form explaining the situation(s) to why they have categorised the appliance AT RISK.

If a gas appliance is classified as IMMEDIATELY DANGEROUS, you should be notified in writing of the reason why a warning label should be attached to the appliance and the gas engineer should be advising you to disconnect the appliance from the gas supply and make safe. 

With your written permission only, the engineer should then cap the appliance from the supply of gas and make safe. 

If you refuse to have the appliance made safe then the gas engineer should ask you to sign a form to acknowledge your refusal and then should contact the gas transporter for the area and inform them of the situation. It is likely that the transporter will visit the property to evaluate the situation and if they see appropriate/are concerned for safety then they are legally empowered to disconnect the supply of gas to your property.

In both instances, an engineer should fully explain the reasons in full to you verbally and answer any questions you may have.


If you are based in Cheltenham, Gloucester, Tewkesbury, Stroud or the surrounding areas of Stroud and you are in need of domestic gas appliance repair, service or installation work then FORTHRIGHT can provide you with highly skilled gas engineers.