How does CO dilution work and why is it useful?
Some combustion gas analysers include a carbon monoxide (CO) dilution function, especially if they’re designed for use with high-powered systems. This function provides vital protection against the potentially harmful gases emitted by powerful or poorly configured heat-generating machines. Here, we take a deep dive into the what, why and how of CO dilution.
What happens if your analyser doesn’t have a CO dilution system?
If your analyser doesn’t have a CO system, it’s not the end of the world. In fact, it’s perfectly fine to bypass this option as long as you take a few precautions:
- Choose an analyser with a robust CO measurement cell that can handle high concentrations without failing. Our Si-CA 030 and Si-CA 130 models fit the bill perfectly – and they’re among a select group of models at this price point that come with cells capable of handling CO concentrations of up to 8,000 ppm. At this level, they’re compatible with the majority of domestic and commercial combustion systems.
- Wait for the CO spike that occurs when a boiler is switched on to subside, especially if the heating body has just been cleaned. CO spikes are perfectly normal: they happen every time the combustion process begins, regardless of the fuel being burned.
- Use a smoke pump for oil-fired boilers in order to avoid nasty surprises due to clogging or improper configuration, both of which will cause the boiler to release heavily laden fumes. Using this type of pump will also protect the smoke filter in the water trap on the probe connector pipe.
- Make sure you set a threshold so that the analyser will shut down if the CO concentration exceeds a certain level. This is very much an exercise in compromise: you want to extend the cell’s lifespan, but you also want to be able to keep analysing and configuring boilers that emit high amounts of CO. For a rating of 8,000 ppm, setting a threshold below 5,000 ppm will make your cell last longer, whereas a threshold of 7,000 ppm will let you work on a wider range of boilers.
Our Si-CA 030 and 130 analysers feature an automatic pump cut-off system, with a user-adjustable threshold of between 1,000 and 8,000 ppm. The threshold on our Si-CA 230 model can be set as high as 10,000 ppm.