How to determine if a carbon monoxide or gas detector is needed

Eliminating ambiguity when choosing detection technology is key to the safety of your home or business, as carbon monoxide and gaseous fuels pose different risks with different detection principles. While a gas detector reacts to the escape of flammable substances such as natural gas or propane-butane, a carbon monoxide (CO) detector monitors the dangerous byproduct of incomplete combustion in heating appliances. The correct choice between these two types of devices primarily depends on the type of fuel you use and the design of your appliances.

Difference in chemical composition and sources of risk

Carbon monoxide is produced during incomplete combustion of any hydrocarbon fuel, whether it is gas, wood, or oil, and its presence indicates a problem with chimney draft or an error in the combustion process. In contrast, gas detectors are designed to detect escaping gas before it reaches the air in concentrations capable of causing an explosion. It is therefore critical to know whether you are dealing with a fuel leak or toxic exhaust gases, as no standard gas detector will detect the presence of CO.

• Carbon monoxide (CO) is colorless and odorless, and is produced when there is insufficient oxygen supply for combustion.
• Natural gas and propane-butane are flammable gases that are released when pipes or valves are damaged.
• Gas detectors do not react to CO, while CO detectors do not detect gas concentration in the space.

When protection against gas is necessary and when protection against CO is necessary

A gas detector is an absolute necessity in any space where a gas boiler, stove, fireplace insert, or gas water heater is installed, especially if the gas is supplied through internal pipelines. In these cases, a leak poses an explosive hazard, so it is a priority to quickly shut off the gas supply, which can be achieved by combining a detector with a solenoid valve. However, if you have a gas boiler with a properly functioning chimney, but exhaust gases are leaking into the interior due to reduced draft, only a CO detector will warn you of the actual risk of poisoning.

In practice, it often happens that apartment owners have only one type of detector installed, creating a safety gap. For example, if you have a gas stove and a gas boiler, a gas detector will warn you of a leak in the pipeline, but will not detect CO that may escape from a faulty boiler exhaust. For maximum safety, we recommend installing a system that combines both functions, or separate detectors at key locations. For comprehensive gas protection, a suitable solution is, for example, the AVANSA 100M gas detector.

Technological principles of sensors and their limitations

Sensors in gas detectors use a catalytic piezoelectric principle (pellistor), which measures the heat generated by catalytic combustion of gas on the sensor surface, while CO detectors work on the basis of an electrochemical cell, which generates an electric current proportional to the concentration of carbon monoxide. These two principles are mutually incompatible within a single standard sensor, because gas detectors are sensitive to other compounds and do not have the ability to distinguish toxic combustion products. Therefore, it is important to understand that one universal detector "for everything" in a single unit does not exist unless it is specifically designed as a hybrid.

In professional practice, we therefore encounter the fact that when modernizing heating systems, it is necessary to consider not only the type of fuel, but also the possibility of CO formation. If you plan to install a new system with automatic shut-off, you can choose a model such as the AVANSA 100M gas detector with a solenoid valve G1" DN25, which ensures immediate closure of the supply in the event of a gas leak, but for protection against CO you will need an additional module or a separate device.

Placement and installation height for different types of detectors

The placement of a gas detector depends on the density of the gas relative to air; natural gas is lighter than air and must be placed high, approximately 15 to 30 cm below the ceiling, while propane-butane is heavier and must be installed just above the floor, about 10 to 20 cm from it. Carbon monoxide has a density similar to air, so its detectors are placed at the height of the human breathing zone, approximately 1.5 meters above the floor, so that they respond to the accumulation of gas in the area where people are present.

Incorrect placement can lead to the detector not reacting in time to a leak. When installing a system with a solenoid valve, it is necessary to ensure that the gas detector is placed near the potential leak source (boiler, gas connection), but not in a place where it could be affected by direct air flow or humidity. For detailed information on the correct height, see the topic Placement and installation height of gas detectors according to gas type.

Combination of detectors and automation of protection

In many cases, especially in industrial facilities or large family homes, it is appropriate to install separate systems for gas and CO detection, with each having its own output for controlling safety components. Modern solutions allow connecting multiple detectors to one central unit, which then activates solenoid valves for individual gas supply branches. This solution is ideal when you have multiple gas sources, as well as multiple combustion appliances that can produce CO.

For simpler applications where it is necessary to protect one main gas source, an integrated system with a detector and solenoid valve, such as gas detector AVANSA 100M with solenoid valve G1/2" DN15, is the optimal solution. This type of system ensures not only an alarm, but also a physical interruption of the gas supply, which is crucial in the event of a leak. If you need higher capacity or a more specific solution for CO, you may consider specialized models such as detector AVANSA 150MC, which is designed for more accurate detection and longer sensor lifespan.

Principle of catalytic piezoelectric gas detection

The sensor uses a microflame, where the gas combusts spontaneously upon contact with a catalyst (platinum), causing a temperature change and a subsequent change in electrical resistance in the wire winding, resulting in a measurable signal proportional to the concentration of flammable gas.

Electrochemical cell for CO detection

Carbon monoxide diffuses through the membrane into the electrolyte, where an oxidation-reduction reaction occurs at the working electrode, generating a microscopic electric current directly proportional to the amount of toxic gas present, without the need to burn it.

Frequently asked questions

Can one detector detect both gas and carbon monoxide?

Standard home detectors are usually specialized either for gas or for CO, as the sensor technologies used are different. Although there are hybrid professional systems, for a regular household it is safer to install two separate detectors in different locations.

How often should gas and CO detectors be calibrated?

The recommended calibration frequency is once a year, while testing the functionality using test gas or a test button should be done monthly. Without regular calibration, the sensor sensitivity may decrease, leading to a delayed reaction in a dangerous situation.

What to do if the gas detector is beeping, but I also smell CO?

Leave the area immediately and call emergency services or the fire department. CO has no smell, so if you feel dizzy or unwell, it is a serious warning of poisoning that must be addressed by a professional.

Conclusion and practical recommendation

Choosing between a gas detector and a carbon monoxide detector is not a matter of preference, but a technical necessity based on the type of your heating and gas supply. For complete safety, the best solution is to install both types of detectors at strategically selected points, providing you with double protection against explosion and poisoning.

Do not neglect regular maintenance and inspection of solenoid valves, which are a key part of active protection in the event of a gas leak. An investment in quality detectors and their proper setup is an investment in the life and health of your entire family, so it is advisable to consult a specialist according to the type of your fuel and the layout of the space.

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