These are the five most common faults that occur in a gas boiler. Some of these breakdowns are easy to fix but be very careful about launching into any DIY repairs without having the proper knowledge.
When handling a gas boiler with water and electricity, it can be very dangerous and there is always a risk of explosion.
Also, most current boilers include an electronic control board that makes repairs very difficult and can cause further problems. In some cases, a boiler may be beyond repair, due to age or the cost of replacing essential parts, in which case you should do a comparison of new combi boiler prices and the repair costs to determine which would be the most cost-effective solution.
Here are some guidelines regarding possible problems and solutions, although the best thing is always to call an experienced boiler repair technician since only the professionals are truly familiar with all the circuits and electronics inside boilers.
Failure of gas
Cause: Sometimes small mistakes like this cause the main problem.
Anomaly: the boiler makes a spark but does not ignite. The burner does not ignite.
Solution: Check that all the gas valves are open, the meter is in order and that gas enters your home.
Water pressure
Depending on whether the problem comes from an excess or a deficiency, it can cause different problems. The correct pressure should be between 1.2 and 1.5 bar with cold radiators. This normally rises up to 2 bars with the heating on.
Causes: If the pressure is constantly low, there may be a leak in the installation. Check all connections between radiators, traps, and pipes. You also have to check the sensor and the water pressure switch to make sure it is not disconnected. If, on the contrary, the water pressure is higher than normal, the problem could be the installation, the safety valve, or the expansion tank.
Anomaly: Problems with the heating of the water; it does not reach the desired temperature. The pressure is 0. The boiler does not turn on.
Solution: To correct the pressure levels, you must manipulate the boiler filling valve until the gauge shows 1.5. You can do it yourself.
Blocking the recirculation pump
Anomaly: The heating system works but the radiators are cold. The temperature rises very fast and suddenly goes off.
Solution: The problem could come from a damaged sensor or a defect in the wiring. It is a serious problem and requires the help of a qualified and registered technician that knows the installation and how to unblock the pump.
Obstruction of the smoke output
Causes: The carbon monoxide released by the boiler is not being evacuated through the outlet duct and the boiler is blocked to protect the home from toxic gases.
It is a very serious problem because smoke is dangerous. If you notice a smell of gas, you must stop using the boiler until the technician comes.
Anomaly: An error appears in the boiler and it does not turn on. The boiler is blocked.
Solution: If carbon (fine layer of fumes) is observed under the heater it indicates that the coil is dirty. A professional technician will have to come to disassemble it and clean it with water under pressure.
Heating temperature probe
This is the device responsible for checking the hot water temperature, to give the order to heat it more or not. If this device fails, it is best to call a specialist to find out the cause of the fault.
Anomaly: The system works but the flame does not ignite, or the heating works but the desired temperature is not reached. Normally the boiler sparks but does not ignite. Hot water does not come out.
Solution: You must first check the burner (the flame) to check whether it burns or not. If it does not turn on, it may be the flushometer or the probe that is defective or dirty. If it works normally, except that it does not heat up it could be the three-way valve that does not work well or the thermostat. In this case, it is best to call a professional to determine the cause of the problem.
