Humans are real creatures of habit. We stick to routines that make us feel nice and comfortable. That’s apparently our nature. There’s also something relaxing about it; if you keep doing things the way you’re used to, you hardly have to think about it and you can focus your energy on things that really need your attention.
When things go the way they go for a long time and rarely yield surprises, the danger is that we stop paying attention. Then sometimes things go wrong that didn’t have to, or performance gradually declines. We often see this happen during the maintenance of relatively simple technical installations, such as flue gas condensers. When designing and installing a heating system, you’re actively involved in it for a while: What kind of condenser do we need? Who makes those things? What do they cost? And how quickly do we earn that investment back? Once things are up and running, such a machine simply does what it's supposed to do, year after year, without any significant problems. Before you know it, it’s no longer on your mind and you have almost forgotten that you have a thing like that next to the boiler or CHP. Sound familiar?
Preventive inspection & maintenance deserve to become a habit. They contribute to the performance and lifespan of your installations and to early detection of defects, preventing malfunctions or serious damage. I would like to explain to you what that means for the flue gas condenser I just referred to.
The flue gas condenser is made of what’s called corten steel. Strong stuff, which lasts a long time and protects itself by forming a layer of iron oxide on the dividing surface with (moist) air or water. Under such a fine layer of rust, steel can keep its properties for a long time, as long as it gets the chance to dry out between operational times.
Fine particles of rust drop down regularly and can build up at the bottom of the condenser. That, too, is perfectly normal. It’s important for this internal dirt to be disposed of properly. This usually happens automatically through the discharge points installed for this purpose; flue gas condensers are self-cleaning, in principle. In the unlikely event that a blockage occurs, an increasingly thick layer of rusty gunk forms, which also stays wet longer and longer.
This has two nasty consequences. The first is that the condensed water no longer drains smoothly and completely. In extreme cases – and I’ve seen this with my own eyes – the excess water from the condenser can run into the boiler. That really doesn’t improve a boiler. The second consequence is that the bottom part of the condenser can’t dry out anymore, so the corrosion there continues unabated. Good chance that after ten years or so the bottom will have rusted through somewhere.
So check the drain points regularly and remove any remaining dirt so that the condenser can continue to perform flawlessly. The manual that comes with it describes the points that need attention. Include them in the spreadsheet or app you use for preventive maintenance, or will use from now on. The long and short of it? Make a good habit of inspection and maintenance.
Joek van der Zeeuw