Water Softeners For Boiler Systems

At Howell Mechanical, we serve residential, commercial, and industrial clients. As such, when we’re creating articles like this one, we have to keep our diverse client base in mind. You see, water softeners should be used in some boiler systems – but not in all boiler systems.


To understand this, you need to know that there are two broad categories of boiler systems: Heating boilers, which are used as the heart of radiant central heating systems, and process boilers, which are primarily used for power generation. Power generation here can mean literally generating electricity (as boilers are used for in power plants), but it can also mean power generation for almost any useful work – many manufacturing facilities use steam boilers to power their machines.


Water softeners are essential for process boilers. They aren’t used in heating boilers – at least, not in Winnipeg. Here’s why:

Water Softeners & Heating Boilers

To understand water softeners, you first need to understand water hardness. Water is sometimes called “the universal solvent” – it’s very, very good at dissolving things, including all kinds of hard minerals. These minerals – especially calcium and magnesium – build up in our tap water. The more dissolved minerals there are in a given amount of water, the “harder” that water is.


Winnipeg’s tap water isn’t particularly hard – we’ve got a good balance of minerals to good old-fashioned H20. Nonetheless, scale (mineral deposits) will eventually form in your pipes, your kettle, and even your boiler. These deposits can cause a range of problems, from creating blockages to causing wear and tear in your boiler.


Water softeners remove minerals from water, which in turn reduces the rate that limescale and other mineral deposits can build up in your boiler.


So why aren’t water softeners used for heating boilers? There are a number of different reasons. The first is that water softeners are somewhat expensive to install, and you can treat the limescale in your boiler by using chemicals that will cost less.


Here’s another thing to consider: System boilers (those that aren’t also being used to provide hot water to your building) are closed-loop systems. That means you’re recycling the same water again and again. That water isn’t going to get harder as time goes on – there are only so many minerals dissolved in the water. That means you don’t have to worry about mineral deposits being constantly added into your system. 


Finally, we need to look at the way water softeners work. The minerals in the water don’t just vanish – instead, they’re replaced by sodium. Sodium has its own set of problems – salty water can attack the inside of your boiler, causing corrosion. 


If you’re already using a water softener, don’t worry too much – just as limescale buildup can be prevented with chemical treatments, so too can corrosion. But if corrosion is a concern, why do process boilers need water softening?

Water Softeners & Process Boilers

Process boilers and heating boilers are two very different beasts. Process boilers:


  • Often run 24/7
  • Are fed water constantly
  • Are more complicated
  • Are more expensive to purchase and repair


All of these factors mean that the quality of feedwater is essential to the longevity and efficiency of process boilers. Scale buildup can be catastrophic, which is why water softeners are a must. They are, however, only one part of the feedwater treatment plan of a process boiler.


Purchasing a water softener for a process boiler is a complicated process – pardon the wordplay. Factors that affect the water softener you’ll need include:


  • The feedline’s diametre
  • The pressure in the feedline
  • The hardness of the feedwater
  • The pH and other qualities of the feedwater
  • The amount of water processed in a given timeframe
  • The uptime of the feedline in a 24-hour cycle (is the boiler ever switched off?)


The consequences of hard water and scale buildup can be severe. A loss of heat transfer due to the scale’s insulating nature is just the beginning. Pipes can become clogged with scale; your process boiler can lose efficiency at a dramatic rate, costly downtime may be required for repairs, and – in the worst-case scenario – your process boiler may fail completely.


Careful consideration should be given to the design of your water softening system. The resin beads that are used to soften your water must be recharged on a regular basis – solids are removed, and the resin beads are flushed with brine to recharge them with salt and potassium ions. 


This process can take a few hours. In a single tank softener system, this leads to hard water filling your boiler during the recharge period. To avoid this, you can opt for a two-tank system – the need for this will depend on the qualities of both your boiler and your feedwater.

Process boiler water treatment doesn’t end at softening

To ensure the longevity and functionality of your process boiler, feedwater must be thoroughly treated. This includes heating feedwater to deaerate it, as well as treating the feedwater with chemicals. Feedwater should be tested daily to ensure its chemical makeup is within guidelines.

Proper Boiler Maintenance Is Essential

…but it doesn’t have to be complicated. We offer boiler repair in Winnipeg, as well as boiler maintenance for residential, commercial, and industrial boilers. Not sure where to start when it comes to water softeners for your boiler? Give us a call.