How To Descale A Tankless Water Heater

Tankless Water Heater

Limescale. A pesky substance that can ruin basically anything that collects water. Whether it’s a kettle or a water heater, you need to make sure that you keep on top of the limescale and calcium that can build up in order to keep your water fresh and your equipment working properly.

That said, it’s a little more complicated to descale a tankless water heater than a tank water heater, for obvious reasons. But fear not! We’ll go over how to get that dreaded scale out of your water heater, and even explain why it’s so important. 

Why Do You Need To Descale Regularly 

Typically, you’ll probably find that scale collects in your tankless water heater a lot slower than it does in a tank, but calcium and limescale can still have a detrimental effect on how your water heater functions. If left untreated, a buildup can clog-up the heating elements and make them less effective. 

If the heating elements are less effective, this means that they’ll have to work harder and use more energy over time in order to get your water up to the right temperature. If you leave it too long, the build up can even restrict the flow of water, meaning that you’ll get lower pressure and less hot water. 

And eventually, if you still don’t get on top of the build up, the walls of your water heater could erode to the point where the whole thing needs to be replaced. 

Luckily, a lot of water heaters actually have alerts that can let you know when the scale is starting to affect their performance. It’s also a good idea to check with a local plumber to find out how often you should be maintaining your water heater, as different areas have a different level of water hardness.

If you live in a hard water area, for example, you’re going to need to maintain it more often than someone who lives in a soft water area. 

How To Descale A Tankless Water Heater

A tankless water heater is going to be installed within the walls, where they’re going to be able to access the water pipes that need to be heated up. You may need to enlist the help of a plumber to begin with to help you find or access your water heater or open up the wall. 

If you have any hesitations at all then it’s a good idea to get a plumber to help for this whole process (at least the first time) as it involves disconnecting the tankless water heater, descaling it, and then reconnecting it. 

So what will a professional do and is it something that you’re going to be able to do yourself? Well, here are the steps that a professional will probably go through in order to descale your tankless water heater: 

The Steps

  1. First of all, the plumber will turn off the water heater and disconnect it from its power source. Be sure to schedule this during a time when you’re not going to need to wash yourself, your clothes,  or your dishes.
  2. They will then close the valves that allow any cold water to enter the heater so that no more water can get into the heater.
  3. After this they can close the valve that connects the heater to the house – at this point, the heater is completely disconnected from everything important.
  4. At this point, the plumber can open the purge valves in order to relieve pressure in the heater. It’s also important at this stage to take care to keep the rubber washers and not to lose them.
  5. The plumber will then attach hosing lines – these need to be specific to the model of heater that you have installed otherwise they won’t be flush.
  6. After the hosing lines are attached, they can open the purge lines again.
  7. Once this setup is complete, the plumber can run vinegar through the heater in order to remove the limescale, this might need to be done a couple of times if there is a lot of build up.
  8. Then they’ll need to flush and drain the heater according to the model’s manufacturing instructions, usually for 45 minutes. You need to get all the vinegar out of the heater otherwise it might affect that water going around your house.
  9. After the heater has been flushed and drained, the plumber will be able to close the purge valves and disconnect the hoses.
  10. The step after this involves reconnecting everything, including the heater to the house’s system and the valves that let water into the heater.
  11. Finally, all the plumber needs to do is turn the power back on and restart the tankless water heater. After this everything should be sorted! 

Do You Need A Professional 

Truthfully? You are most likely going to want to hire a professional and make sure that everything goes smoothly.

This is because all of the drinking water in your house needs to go through your water heater, and if anything goes wrong you could jeopardize your water if anything happens to go wrong or you descale it incorrectly.

Common problems could include using harsh chemicals to descale the heater that you would end up drinking, or even leaving a valve open. 

If you have experience with plumbing and feel competent enough it could be something that you are able to do, however there are a lot of things that can go wrong that could leave you without water for as long as it takes to get an actual professional out to fix any issues you have. 

It’s always going to be better to hire a professional plumber to come in and descale your water heater to avoid any incidents. 

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