An annual boiler service is essential to keep your boiler operating efficiently and with out any faults. It should be carried out once a year by a Gas Safe registered engineer, who performs essential safety checks and cleans the boiler’s internal components. An annual servicing is usually required to keep your manufacturer’s warranty valid.
At Safe Plumber’s our annual boiler service includes an in-depth inspection and service of your boiler.
Below, we cover every step our Gas Safe engineers carry out — so you know exactly what to expect.
1. Electric Current Isolation
The very first step that our Gas Safe engineers will do is to isolate the electric supply to the boiler. We isolate the boiler since gas boiler are connected to the main power supply. During, the annual boiler service we are going to inspect the internal components that carry electricity hence we will isolate the electricity. We will ensure there is no electrical power going to the boiler using a voltage detector before proceeding any more steps.
2. Cleaning the condensate trap
During an annual boiler annual service, we clean several components of the boiler. Condensate trap purpose is one of the components that we clean. Its function is to collect the acidic wastewater produced by the boiler. If we do not clean the condensate trap, this will result in blockage and poor boiler performance. We first remove the remove pipe, and then turn the trap clockwise to disengage and lift to remove the trap. The trap is made of plastic. Once, the trap is removed we then clean it by emptying the trap.
3. Cleaning the Magnetic Filter
Most boilers nowadays come with a magnetic filter. Similar to the condensate trap, we will clean the magnetic filter. The purpose of the magnetic filter is to attract the steel sludge that is produced in your boiler. This mechanism allows clean water to flow through your pipes, so it is very important to clean the magnetic filter
4. Expansion Vessel Check
In this part of the boiler annual service, our Gas Safe engineers will inspect the expansion vessel check. Unlike the magnetic filter and condensate trap, the expansion vessel does not require cleaning. The purpose of the expansion vessel is to regulate pressure as the water expands and contracts during operation. If you are experiencing low water pressure, we have a well-written article that explains how to fix low water pressure in your boiler.
A faulty expansion vessel can result in the boiler pressure to drop. A low water pressure can be because of many reasons but a frequent one is related with expansion vessel. If you own a Vaillant boiler and it is displaying the F22 error code this can be related to the expansion vessel.
5. Venturi Cleaning
The Venturi is a key component of a boiler, and its function is to control the air-to-gas mixture before combustion takes place. It is a highly technical and essential component of a gas boiler. Our Gas Safe engineers will clean the Venturi component as part of the annual boiler service.
6. Fan and Pump Inspection.
This is an inspection stage of the annual boiler service. We will inspect the fan and pump. At this stage, we let you know whether either component needs to be replaced. If your boiler is serviced regularly, the chances of needing to replace either component are very low.
7. Full Strip Cleaning of the Main Heat Exchanger
One of the most important components in a gas boiler is the Heat exchanger. This is the piece of equipment that is the main responsibility is the production of heat and hot water. With the boiler case removed and the top plate off the gas engineer will proceed on dismantling the remaining parts to access the heat exchanger.
Note: this kind of cleaning should be done only by a gas safe engineer.
8. Combustion and Flue Gas Analysis
This is likely the last step in the annual boiler gas service. At this stage, we will use a gas flue analyser to benchmark the boiler’s flue gases and combustion performance. Benchmarking is a legal requirement, as well as a warranty requirement to keep the warranty valid.. For example: if you call the manufacturer about an issue, they will likely ask for the benchmark report to find out whether the boiler has been installed correctly or not.
For most modern domestic gas boilers, the Co/Co2 ratio should be below 0.004.
9. Central Heating and Hot Water Temperature Adjustment
This is the final stage, assuming everything above went perfectly fine. We will correctly set the temperature. Lower temperatures usually mean greater energy efficiency, but during the winter, this can be adjusted to a higher temperature.
Annual Boiler Service: Quick Checklist
Here’s a summary of everything covered in a Safe Plumbers annual boiler service:
- ✅ Electrical supply isolated and verified safe
- ✅ Condensate trap removed and cleaned
- ✅ Magnetic filter cleaned
- ✅ Expansion vessel pressure checked
- ✅ Venturi cleaned
- ✅ Fan and pump inspected
- ✅ Heat exchanger fully stripped and cleaned
- ✅ Combustion and flue gas analysis completed (benchmark recorded)
- ✅ Flow temperatures checked and adjusted
When is the best time to carry out an annual boiler service?
Usually, around a month before your annual boiler service is due. However, we recommend carry out the service in late summer or early autumn, before the heating seasons beings.
Do you offer annual boiler service?
Yes, we are Gas Safe registered and we offer annual boiler service in Kensington and surrounding areas such as Notting Hill with same-day availability and no call-out fees.