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Serving Orange County

- SINCE 1981 -

Serving Orange County

- SINCE 1981 -


Hours: Monday-Friday 7:30-5:30PM
Saturday: 8:00-1:00PM


Saddleback Plumbing Heating & Air Blog

How Boiler Kettling Harms Your System

If your boiler makes a deep rumbling noise while it’s operating, don’t ignore it. That noise is a symptom of a problem called kettling, which is a serious threat to the system. If the problem isn’t dealt with quickly, it can cause quite a bit of damage to the boiler. Read on to find out what causes this issue, and how to deal with it.

Lime Scale

Boiler kettling is caused by the buildup of lime scale in the heat exchanger, which is the pipe that water flows through while it’s being heated. As the lime scale builds up in the pipe, it restricts the flow of water through the exchanger. This causes the water to become trapped in the heat exchanger. Not all boilers are designed to actually boil water, which means that it’s a problem when water starts to boil in the heat exchanger.

Water expands around 1500 times when it evaporates into steam, which puts an immense amount of pressure on the pipe. The rumbling sound you hear during operation is the sound of the heat exchanger struggling to cope with the added pressure.


Kettling will cause a substantial drop in the efficiency of the boiler system, which is the initial problem. The larger issue, though, is that if the problem is not corrected the heat exchanger might eventually rupture. Most boilers have safety features in place to prevent that from happening, but they will shut down until the issue is fixed. If you notice your boiler kettling, you should call for repairs as soon as possible.

Saddle Back Plumbing offers a full range of boiler repair services throughout Laguna Hills, CA. If you need boiler repair services, call today to schedule an appointment with one of our technicians. We’ll make sure that your boiler serves you well this winter.

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