Often, people wonder why they should treat boiler water. Water is dead and I have never experienced any problems with my water? Do not underestimate the quality of the water that runs through the boiler. Often, one mistakes black water for ‘dead’ water. The black color indicates everything but dead water. The black color comes from black filth which is magnetite, an oxidized form of iron. Magnetite emerges in oxygen-poor environments and forms a black, protecting layer inside the boiler’s pipes. Due to leakage and/or suppletion of water, oxygen enters the system and magnetite is formed continuously. Because of this, a thick layer is formed, which is eventually loosened into the water. This is very likely to lead to malfunctioning, corrosion, leakages and loss of the boiler’s efficiency. In the end the boiler could even completely stop working. Besides the problems described related to the emergence of magnetite, still standing water could also lead to extra problems.

The fact that the use of boiler systems in horticulture is often seasonal, results in (parts of) systems being switched off for months. However, stagnation causes deterioration. Without a flow, there’s no control over the boiler system. Contamination could drop and stack up in the pipes of the system, resulting in bacteria quickly multiplying and corrosion developing. By implementing management for water stagnation, the chances of the water causing problems is minimalized. You could ask yourself: do the problems caused by water stagnation weigh up to having the system pump once in a while?  

It is often a misconception, that in closed systems you do not have to worry about the water. The system is closed in a way that, if everything functions properly, no water exits the system. However, this does not mean that nothing can enter the boiler. Especially the entrance of oxygen through suppletion water, seals, an open buffering tank or a plastic/PE boiler hoses could be the cause of problems. A sudden stop of the system due to leakage generates damage and high costs in terms of the system, but possibly also at the expense of the crops. This is the result of climate problems emerging within the greenhouse. That’s why it is recommended to closely monitor the state of the boiler system and in order to limit possible fluctuations where you can. 

Attention for monitoring the water within a boiler or cooling system, could save a lot of difficulties. It provides more insight into critical factors, that might prevent problems and failure of the system. In addition, quick action can be taken when problems are remarked. One should take into consideration that a beautiful and clean system on the outside does not necessarily mean that the inside is in a good state. Partly due to the loss of water and the use of ‘bad’ suppletion water, water in boiler systems generally is of mediocre quality. If the flow division in the system is not regulated properly, a delay in the crop’s growth and/or plant stress can be the effect. 

There are many types of water, each with its own pros and cons; tap water, softened water, osmosis water, water-basin water, mineral water, surface water, etc. What is most important, is the fact that the water used in a boiler system should always be crystal-clear. Hard water could cause deposit, leading to clogging or a decreased transfer of warmth. By nature, chalk protects from corrosion. Basin water and surface water are cheap, but contain many bacteria and/or organic matter. These are also likely to form deposit, due to which systems silt up and get difficulties transferring warmth. Always make sure to use water of good quality when (re)filling your system. And only refill when absolutely necessary in order to prevent oxygen from entering your system. Mineral water or surface water are recommended for refilling a modern boiler system with a large content. Well filtered, clear rain water or decalcified water with a low concentration of chlorine are preferred.

Make sure to maintain alkalinity within the water, so that the steal within the boiler system is protected from damage. The right pH value is difficult to achieve when making use of basin-, rain- and osmosis water, because these types of water are not buffered and do not contain any alkalinity.  At the same time, basin water contains a lot of oxygen, which damages metals. Therefore, water treatment is always needed to add alkalinity to the water and to bind oxygen. It is recommended to frequently control both parameters. 

Water is used throughout the entire cooling tower, for carrying away warmth. In open systems as such, evaporation of water is a constant process. Only clear water evaporates, leaving salts originating from this water, behind. Because of this, the saltiness of the remaining and circulating water keeps increasing. Chalk and damage in metal parts can be the result of this high concentration of salt. Salt is corrosive on the majority of metals. The evaporated water is moved outside through a fan forming fine mist. One of the bacteria that can survive in a recirculating process water system is Legionella. In specific circumstances, this bacterium could cause deathly inflammation of the lungs. Because of this danger, the obligation to monitor your cooling tower by means of a plan, is implemented. In this plan, the minimization of risks should be described. 

Cooling towers ask for very specific water treatment and control in order to prevent ecologic contamination, chalk and corrosion. Because the systems are open, they are sensitive to contamination blowing in by the wind, meaning they are constantly fed with micro-organisms from the air. Excessive formation of silt and undesired growth of bacteria can be a result. Underneath this slit, very local damage of the pipes can happen. When periodically controlling and treating your water, the functioning of the system is monitored with extra attention for as few problems and malfunctions of the system as possible.

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